Researching the Luftwaffe through Prisoner Interrogations
"SECRET A.D.I.(K) Report No.160/1944
THE FOLLOWING INFORMATION HAS BEEN OBTAINED FROM P/W AS THE STATEMENTS HAVE NOT AS YET BEEN VERIFIED, NO MENTION OF THEM SHOULD BE MADE IN INTELLIGENCE SUMMARIES OF COMMANDS OR LOWER FORMATIONS, NOR SHOULD THEY BE ACCEPTED UNTIL COMMENTED ON AIR MINISTRY INTELLIGENCE SUMMARIES OR SPECIAL COMMUNICATIONS. A G.A.F. PATHFINDER UNIT. Further Report on Ju.88 S-1, Z6+IN, of 5/K.G.66, brought down in the sea off Brighton on 25th March 1944. (Previous A.D.I.(K) Report No.141/1944). 1. The present report may be taken as the third of a series - the first two in which were A.D.I.(K) Reports Nos. 64 and 108/1944 - dealing with the most recent G.A.F. pathfinder practice. 2. The principal subject of interest which has emerged from the interrogation of the one survivor of the Z6+IN is the employment by his Staffel of a method of target pinpointing known as the Egon procedure. 3. Since the issue of the last pathfinder report, the pilot of the Z6+HK, who was wounded when shot down on February 24th, has become available for interrogation and he has also contributed to the information which this report contains on the activities of I/K.G.66. EGON PROCEDURE 4. On the night of 24th/25th March, the Z6+IN of 5/K.G. 66 was engaged in pathfinding for the attack on London; the petrol tanks were holed by A.A. fire and on the way home the aircraft came down in the sea through lack of fuel after the crew had baled out. 5. The Z6+IN, which was equipped with the FUG.25a, FUGe.10, FUGe.16, PeilGe.6 and the FUGe.216 ("Neptun") tail warning device - the latter out of order - had laid its flares by means of course and pinpointing data supplied by its own ground control. 6. This system of controlling aircraft from the ground is known as the "Egon Verfahren" (Egon Procedure) and in operation depends upon response radiated by the FUGe.25a in the aircraft being picked up and D/F'd by two Freyas. 7. During flight, the position of the aircraft is continuously plotted by means of data supplied by the Freya and necessary course corrections are passed to the aircraft by ground control in the form of coded W/T and R/T signals. 8. Orders for flare or bomb release are similarly transmitted, allowances for drift being taking into account by the plotting centre; an accuracy to within 0.3° - or according to P/W about 200 metres - is claimed for the placing of the flares. (It should be noted that 0.3° at a distance of as little as 150 km. is nearer 900 m.) 9. The Egon Procedure at present being used, relying as it does on course and bomb-release signals passed by W/T and R/T, is as yet only in an extemporised form. A new attachment to the FUGe.25a in the aircraft will shortly provide for visual signals appearing on a Cathode Ray Tube and will eliminate all W/T and R/T course and bombing signals without basically altering the present procedure. 10. This attachment is now being tried out by 4/K.G.66 at Strausberg and according to P/W it is about to be introduced into operational use; the apparatus and its method of operation are described in a later section of this report. Operation of Egon Procedure. 11. At the briefing for a pathfinder operation, crews are given a course to the target and a height at which the flares or bombs are to be released. 12. After take-off, the FuGe.25a in the aircraft is switched on and Freya No. 1 plots the aircraft; the FuGe.25a radiations giving the single-letter recognition characteristic of the aircraft are received by the Freya and range and bearing data are passed from the Freya to the plotting room. 13. The Egon plotting table is similar to the night-fighter Seeburg Tisch; a transparent map of the area of operations is laid on a glass table and the aircraft is represented by a red spot of light which is thrown on the underside of the glass by an automatic projector connected directly to the Freyas. The course of the pathfinder aircraft can thus be followed visually and any corrections necessary are given by Control. 14. In the vicinity of the target Freya No.2 takes the aircraft over from Freya No.1 and thereafter no further course corrections, but only the flare or bomb release instructions, are given. 15. The height of the aircraft cannot be checked by the ground Control and it remains with the pilot to see that his height at the time of release conforms with the instruction given at the briefing. 16. When marking targets over London the aircraft were usually briefed to fly over southern England at 9,500 metres, reducing height to 8,500 metres to release the flares. The height of flight given at the briefing for Egon-controlled aircraft was never less than 6,000 meters over London. Communication with Aircraft. 17. The whole of the Egon procedure depends in its operation on a short series of code-words used in communication between Control and aircraft; these code-words are already familiar, having been borrowed from the G.A.F. controlled nightfighters. 18. It, was stated by P/W that recently the R/T channels of communication had been seriously disturbed by British countermeasures and to combat such interference it has recently been the practice to transmit all traffic passing from Control to the aircraft in R/T and W/T simultaneously, the latter in two different channels. 19. The R/T traffic passes on the frequency band of the FuGe.16 whilst both the W/T channels are within that of the FuGe.10 and PeilGe.6. One of these two W/T channels is received by the aircraft on the PeilGe.6; this is on a frequency of 563 kc/s., the signals being superimposed on the broadcasting programme of Calais I - the familiar vehicle for the outpourings of one William Joyce. The other is received on another frequency on the FuGe.10, 20. The series of signal code-words, their equivalents in the morse channels and their significant in the procedure are as follows:- W/T R/T Meaning (Preceded by a/c call-sign) KKK Kommen You are being plotted. AAA Autobahn Change bearing to..... RRR Rolf Bearing 5° right. 2 RRR Zweimal Rolf Bearing 10°right. LLL Lisa Bearing 5° left. UUU Kirchturm Height CCC Caruso Fly straight and level cours. ZZZ Pauke Pauke Open bomb doors. -(dash) -(W/T dash) Pre-release signal of 3-4 secs. .(dot) .(W/T dot) Bomb or flare release signal. ? Kurfürst Acknowledge that signal is understood,(reply on FuGe.25a) AAA HHH Autobahn Mat Set course for base. (Heimat). 21. In operations the first signal which passes from Control to the aircraft is the information that Freya No.1 has engaged the aircraft and plotting has commenced. This signal opens with the aircraft call-sign, e.g. CA1, followed by KKK or Kommen; in subsequent signals the two letters of the aircraft call-sign are omitted and the number only given. 22. The aircraft has no communication with its control but replies to this and other signal, by manipulation of the FUGe.25a - switching off for 3-4 seconds signifying that the signal has been received and understood and repeated switching off and on signifying the contrary. 23. Course corrections are passed to the aircraft in units of 5°, represented by the code-words Rolf or Lisa or their morse equivalents; thus Rolf or Lisa = 5° and three times Rolf or Lisa = 15°, In passing such instructions, Control signals the aircraft's call-sign followed by the following type of message:- R/T: Autobahn dreimal Rolf. W/T: AAA - 3 - RRR. 24. Whilst the aircraft is being followed by Freya No.1, any necessary corrections in course continue up to the point where the order is given to fly on a straight and level course after which no further course corrections are made and orders for release of flares follow. 25. When the aircraft is in a position to commence the bombing run the order "Pauke Pauke" (open bomb doors) is given, at which point Freya No.2 takes over and a pre-release signal of a single dash is given, followed by a release sign of a single dot. 26. The aircraft then signals "Quitting" (operation completed) by manipulation of the FUGe.25a switch, Control gives the order to return, and the aircraft is vectored back to base. 27. It is noteworthy that for this purpose again the subterfuge of Calais I has been resorted to; on the last flight of the Z6+IN the crew was briefed to return to Montdidier unless the march "Kommt zurück" ("come back") was played by Calais; on hearing this tune a landing was to be made at Soesterberg. "Kommt zurück" was duly played and the Z6+IN was on its way to Soesterberg when it came to grief off Brighton. 28. It was stated that with the Egon procedure it was possible for the ground control to direct one aircraft every ten minutes; it is the practice, however for the flare dropping aircraft to orbit the target after release of one cluster of flares and to be controlled in a second run over the target after an interval of six minutes to renew the concentration before the first flares have burned out. EGON GERAT - FUG.25a ATTACHMENT. 29. The introduction of the attachment to the PuGe.25a, consisting of a Cathode Ray Tube presentation unit, will dispense with all W/T and R/T signals as navigational aids in the Egon Procedure. 30. The attachment, which was invented and tried out at Rechlin by one Stabsingenieur BENES, consists of a unit placed in the fuselage of the aircraft and a presentation unit, placed between the pilot and observer, embodying a Cathode Rey Tube of about the same diameter as that of the Lichtenstein. 31. The attachment was thought by P/W to have a common aerial array with the FUGe.25a, the latter aerial being a rod about 35 om. in length. 32. The scale of the Cathode Ray Tube consists of a circle divided into equal segments, each of which represents, and is marked with, one of the code-words used in the Egon Procedure. The circle is surrounded by an outer circle which is marked clockwise from 0 to 9, the 0 being at 12 o'clock in the circle, so that the whole scale has much the appearance of a dartboard. 33. In operation, the Egon Procedure will be followed in the manner already described, but the visual signal on the tube will replace the aural signals at present in use. 34. A short blip, radiating from the centre of the tube, first appears in the segment representing the appropriate signal, such as "Autobahn". Bearings are than given in the same way by a long blip, also from the centre, appearing opposite a succession of figures in the outer circle, for instance 3 followed by 5 and 5 repeated represents 355°. 35. Course corrections can similarly be given by a short blip appearing for example, in the "Rolf" segment followed by a long blip opposite 3 in the outer circle, which would mean '3 times Rolf' or a correction of 15° right. 36. Height can similarly be given by indicating "Kirchturm", followed by the necessary figures. TARGET MARKING PROCEDURE. 37. According to the pilot of the Z6 + HK, which was shot down on 24th February 1944, the Verbandsführer - Master of Ceremonies - is being employed in target marking procedure; this was denied by the P/W from the Z6+ IN, who was in another Staffel, but the pilot of the Z6 + HK claims to have acted as Verbandsführer on his last operation. 38. It was stated that the first pathfinder aircraft and the Verbandsführer arrive simultaneously over the target and when the pathfinder aircraft lays the first flares their position is checked by the Verbandsführer from a higher altitude. 39. If the flares have not been correctly laid, the Verbandsführer drops a single red flare, which he places above the false cluster as a sighn to the attacking force; by then himself proceeds to place flare in what he considered to be the correct position. If by now the attacking force to nearing the target, he is said to inform the formation leaders by R/T in clear of the change in marking and that the false cluster is to be ignored. 40. It is noteworthy that both of the present P/W were convinced that decoy flares have been dropped on several occasions during attacks; P/W stated that this would be countered by the Verbandsführer announcing this by R/T and/or dropping a flare of a different colour. 41. The burning time of the normally used single candle flare, the Mark.C.50, is given as seven minutes and these are renewed by the pathfinder aircraft, with the help of navigational aids, in their sixth minute of burning. 42. The normal load of flares carried by the pathfinder aircraft is eighteen Mark.C.50's; these are dropped in three runs with six on each run, or alternatively in two runs of nine. I/K.G.66. Order of Battle. 43. According to the most recently captured P/W, I/K.G.66, although it has for some time had a strength of five Staffeln, is still nominally one Gruppe. Up to 25th March 1944 the disposition and equipment of these Staffeln were as follows:- Staffel Equipment Base 1&2/K.G.66 Ju.88 S-1 Avord, forward base Ju.188 Montdidier. 3/K.G.66 Ju.88 S-1 Cormeille-en-Vexin. Ju.188. 4/K.G.66 Ju.88. Strausberg Ju.188. 5/K.G.66 JU.88 S-1 Avord and Montdidier. 44. Up to about the first week in March the 1st, 2nd and 5th Staffeln were based at Montdidier but continued attention from Allied aircraft, including a fighter-bomber attack in which three aircraft were destroyed, forced a move further back to Avord, K.G.40 being ousted from that airfield in the process. 45. Aircraft of all three Staffeln still used Montdidier operationally, however, and fuelling facilities were available there; it was usual to fly from Avord to this airfield immediately before starting off on operations. 46. Major SCHMIDT is still Kommandeur of I/K.G.66, he just escaped being written off recently, however, when his aircraft was shot down by Mosquitoes between Avord and Montdidier. His crew was killed. 47. Hauptmann SCHMIDT, the Staffelkapitän of the 2nd Staffel, was lost in the attack on Hull on 19th March; his successor is not known. 48. Oberleutnant de MILDE, a signal officer formally at Halle is Staffelkapitän of the 3rd Staffel and Oberleutnant BÖHMANN now commands the 5th Staffel. 49. The 5th Staffel has sixteen officers on its strength, most of whom are signal officers. Two of these are Leutnant SCHUBERT and Leutnant MEUHAUSER. ACTIVITIES OF I/K.G.66 50. It must be emphasised that recent P/W of K.G.66 have had small knowledge of the activities of other Staffeln of the Gruppe beyond their own; the W/T operator of the Z6+IN, although he claimed a knowledge above the average, must be classed with the other P/W since his information was mainly from hearsay. He, like the others, can only be relied upon where his own Staffel is concerned. 51. The 5th Staffel was formed in about May 1943 from personnel of the 3rd Staffel, with the addition of some crews from K.G.6. Losses, which have been heavy, have since been replaced with crews from the other Staffeln of K.G.66 as well as from K.G.54 and K.G.2. 52. This Staffel commenced operations with target marking by D/R but in about December 1943. December 1943 the Egon Procedure was practised at Rechlin and later on from Montdidier. 53. According to this P/W the activities of the Staffeln of I/K.G.66 are at present divided as follows:- 1st Staffel.... thought to be engaged as backers-up. Navigational aid used uncertain. 2nd Staffel.... Pathfinding, using "Gee" (see A.D.I.(K) 108/1944). 3rd Staffel.... Known as the Störstaffel (jamming Staffel). Radar investigation and jamming flights. 4th Staffel.... Non-operational: perfecting new Egon apparatus as well as trying out a "Queen Bee" aircraft. 5th Staffel.... Known as the "E" Staffel: pathfinding using the Egon Procedure. INVESTIGATION AND JAMMING. 54. The Störstaffel - the 3rd - is said to have commenced operating in August 1943 in the fields of the anticipation and attempted diversion of Bomber Command night attacks. 55. A few Ju.88 S-1's of this Staffel are variously equipped with the Hyperbel Gerät, the "Naxos" search receiver such as is used in U-boots for the detection of Radar transmission, and a set known as the "Viktor 1" for jamming R/T. 56. In operations, an extra member of the crew is carried - an English speaking signals officer - sometimes the aircraft may be fitted with drop tanks. 57. When making investigation flights with the object of anticipating Bomber Command's targets, the aircraft are allotted specific areas of operation - the area off the North Sea coast between Boulogne and Denmark has the code-word "Rodelbahn" - and the first duty of the special W/T operator is to discover any British navigational aids which may be in operation. 58. The frequencies and bearings of such transmissions are passed to a plotting centre which, using data from several investigating aircraft, instigates counter-measures to the navigational aids and the laying of decoy flares short of the conjectured target. 59. Should the British navigational aids in use be discovered in the earlier stages of an attack, the practice is said to be to withhold any countermeasures until the later stages, to ensure that no intermediate evasion of these countermeasures can take place. 60. It was stated that the Staffel was at present only making these investigational flights as far as Western Germany but that they had already claimed some successes in their efforts to divert attacks. FW.190's ON NIGHT OPERATIONS. 61. It was stated that the, F.W.190's of S.K.G. 10 which use Rosières and an airfield in Holland as their bases are now equipped with FuGe.25a and controlled by the Egon Procedure. 62. Several pilots of the F.W.190's are said to have reported wonderful bombing results before the installation of the FuGe.25a took place, whereas they in reality merely made a pleasant flight over some innocuous area and jettisoned their bomb. With the introduction of the FuGe.25a many of the pilots who did not understand its functions are said to have found themselves facing a court martial. 63. The signal to the F.W.190’s to remain over the target was stated to be "Walzer" and the homing signals the words "Radetzkymarsch". A.D.I.(K) S.D.Felkin 5th Apl.44. Wing Commander AMENDMENT TO A.D.I.(K) REPORT NO. 160/1944. Paragraph 27: Delete and substitute:- "27. It is noteworthy that for this purpose again the subterfuge of Calais I has been resorted to. In the last flight of the Z6 + IN the signal for the crew to return to Montdidier was to be the tune "Komm' zurück, ich warte auf dich" (well known in this country under the title of "J'attendrai") played every three minutes by Calais; if this tune was not played, the crew was to land at Soesterberg. "Komm' zurück" was duly played and the Z6 + IN was on its way to Montdidier when it came to grief off Brighton. The pilot of the Z6+HK also referred to a procedure of this nature. He stated that the playing of a waltz was the signal to remain over the target and the Radetzky March the signal to return to base. No doubt the tunes played and their significance would be varied from sortie to sortie." Paragraph 63: Delete." then in a second file this ... "Further Report on the Crew of the Ju.88 8-3 Z6 + FH of 1/K.G.66) shot down by A.A. 5 miles N.W. of Alost, on 23rd January 1945. (Previous A.D.I.(K) Report No.142/1945) LAST FLIGHT. 1. It will be remembered that this aircraft was brought down while acting as pathfinder to a minelaying operation in the Scheldt Estuary. The flight was described in detail in the previous report and there is only one point of interest to add; that after marking the minelaying point at the mouth of the Scheldt, the Z6 + FH was to go on to attack the night fighter airfield at Knocke/Le Zoute, for which purpose 18 x 50 kg. S.D. bombs were carried. If the lighting at Knocke airfield was not on when the crew reached it they were to use their bombs on A.A. batteries as targets of opportunity. I/K.G.66. 2. It is confirmed that 1/K.G.66 based at Dedolstorf has reverted to its old duties as a specialised pathfinder unit. It is organised in the same way as when it operated against England in the spring of 1944, that is to say with the 1st Staffel using the "Y" procedure, the 2nd the "Truhe". (the German equivalent of Gee), and the 3rd the EGON procedure. There is, however, one important innovation; the lst Staffel has been receiving instruction in a new navigational method, a combination of the "Y" and Egon procedures, which will be described in a later section of the present report. 3. P/Ws' knowledge of the Gruppe's activities was confined to their own Staffel; they knew that the 2nd Staffel used "Truhe" and that there were a number of German Gee stations, but they did not know the locations of the latter and could give no further details. 4. Shortly before the crew of the Z6 + FH was shot down, the 1st Staffel had received three new crews, bringing their strength up to 12. Aircraft for these new crews, however, had not yet arrived. ACTIVITIES. 5. The present crew had joined 1/K.G.66 at Dedolstorf in May 1944, having previously been with 4/K.G.54, with which unit they had flown 7 operations in Italy and 10 against this country. 6. At Dedolstorf they did little or nothing during the summer of 1944 beyond some very scanty training and they did not make their first operational sortie until December 4th; this was a weather reconnaissance over an area of the North See East of the Thames estuary in preparation for a mining sortie in the Scheldt that same night. 7. In about October or November it had been known in K.G.66 that the Germans believed the Allies to be planning a largescale landing in the Bay of Venice, suit that K.G.66 was to be moved South to take part in a "Total Einsatz" (full-scale operation) against it. The landing did not, however, materialise. 8. At the beginning of VON RUNDSTEDT's offensive a number of aircraft of K.G.66 were detailed to mark an area near Eupen where paratroops were to be dropped. The operation was kept a close secret and members of the unit were forbidden to write home until the flight had been completed. Some of the paratroops were dropped from Ju.52's of T.G.30; about 100 aircraft in all took part in the mission. 9. A few days later 4-5 aircraft of 1/K.G.66 took off from Dedolstorf to act as pathfinders for a bomber force in an attack on some woods to the North of Bastogne which were stated to conceal a concentration of artillery. They were accompanied by 3-4 Ju.88 A-4's of K.G.200, the crews of which were receiving pathfinder instruction from K.G.66. 10. When the K.G.66 aircraft arrived over the target the weather was very bad with low cloud and poor ground visibility and as the crews could not identify the target they returned home with their markers. The crews of K.G.200, however, being new to this kind of operation, decided to drop their markers rather than return with them, the result being that the wrong target was marked. 11. The Kommandeur of I4.1.66 made a complaint to Generalmajor PELZ and soon afterwards the aircraft of K.G.200 were withdrawn from Dedolstorf. 12. At about Christmastime some 12 aircraft of 1/K.G.66, six of them acting as pathfinders and illuminators and the remainder as normal bombers, flew another sortie to the Bastogne area. They flew on a course Dedolstorf - Hanover - Paderborn - Bonn/Mangelar airfield (marked by a searchlight dome) a light beacon at Trier - a point immediately behind the German lines, where the starting point of the target marking run was indicated by Flak star shells. From the latter point the present crew flew by D/R for about two minutes on a given course and at a given height before releasing their flares and ground markers. TARGET MARKING. 13. The flight to the Bastogne pocket described above gives a typical instance of the method of navigation used by those aircraft of K.G.66 which did not employ special navigational aids. The target marking run was flown on D/R and just before the target was reached the aircraft began dropping their flares. Ten of these were dropped in a straight line at tensecond intervals - i.e. about 1000 metres apart - and laid so that the centre of the line was over the target. The aircraft then made a 180° turn, identified the target by the light of the flares and then dropped coloured ground markers, usually green, on the target itself. 14. The normal load carried was ten flares and two A.B.250's containing ground markers. The flares were released from a height of 2000 metres; they illuminated at about 1200 metres and burned down to 200 metres above ground. LUX BUOYS. 15. The Lux buoys used by K.G.66 for minelaying operations and, as stated in the previous report, used by certain aircraft of the Gruppe whilst pathfinding for at least one V.1 launching operation, are carried in A.B.250 containers. The containers can, of course, be released from any height but they must be fused to open, releasing the Lux buoys, at a minimum height of 200 metres. 16. P/W said that in very clear weather the Lux buoys could be seen at a distance of about 20 km. from an aircraft flying at a height of 2000 metres. NAVIGATION. 17. As befits a pathfinder unit, K.G.66 treats the question of navigation as of primary importance during briefing. Full details of W/T and visual beacons, Sonne, and other navigational aids are given to the crews at least two hours before take-off to allow ample time for study, and the observer of the present crew states that with these aids it is very difficult to go wrong unless the radio apparatus refuses to function. 18. If the flight has gone according to plan the operation is not examined in detail at the subsequent interrogation, but if anything has gone wrong the latter is investigated very thoroughly and the observer had to make a full report. SPECIAL NAVIGATIONAL AIDS. Egon. 19. It was stated in the previous report that a detachment of K.G.66, consisting of three crews of the 1st Staffel and four crews of the 3rd Staffel, was sent about the middle of November 1944 to Zwischenahn where they were told that they would have to fly sorties under Egon control in conjunction with He.111's carrying V.1's. 20. During the first fortnight in December the crews carried out a certain number of Egon practice flights but the weather was so bad that the present P/W, who were members of the party, made only one flight. This was to Texel and the aircraft experienced severe icing conditions both on the outward and homeward routes. Possibly as a result of the aerials icing up they received no instructions from the ground; on returning to base they were told that the Freya had plotted them the whole way to Texel and back and had sent them instruction, but had received no response. 21. The observer states that the usual operational height for the Egon procedure is up to 4000/5000 metres, at which height the maximum control range is about 350 km. "Y" Procedure. 22. The present crew returned from Zwischenahn to Dedolstorf about the middle of December. Up to this time none of them had received more than theoretical instruction in the "Y" procedure, but about a week later on December 20th/21st, the W/T operator made one flight as a member of another crew undergoing "Y" training. 23. This flight was from Dedolstorf to Wittenberg, about 100 km. to the E.N.E. The aircraft was controlled from a "Y" installation at Dedolstorf consisting of one single mast with a small aerial array at its head of which P/W could give no exact description. Instructions were passed to the aircraft over the FuGe 17 and when the ground control wanted to fix the aircraft the W/T operator of the crew depressed the "Y" key on his FuGe 17 for five seconds on request. 24. The flight was a failure. The "Y" beam became bent owing, P/W thinks, to variations in the electric main current, which fluctuated between 220 and 180 volts, and when the bombing signal was received the aircraft, although still on the beam, was at Magdeburg, some 95 km to the South of Wittenberg. 25. The next day the Staffelkapitän of 1/K.G.66 undertook a similar flight, which was more successful. When he received his bombing signal he was over Seehausen, only a few km. S.W. of Wittenberge. The New "X" Procedure. 26. This new procedure is basically a combination of the "Y" beam and the Egon procedure. A "Y" beam - referred to by P/W as "Oskar"; the code name known to have been applied to the original "Y" beam used in 1940 - is employed in conjunction with the FuGe 28, the FuGe 25a and a clock which P/W called the "Y" clock, but which appears from their description to be similar in principle to, if not identical with, the "clock" reported in April 1944 as having been devised for the Egon procedure. (A.D.I.(K) 160/1944). 27. The knowledge of the present P/W on the new procedure was only derived from theoretical instruction. They had heard whilst at Zwischenahn in December 1944 that the system was to be introduced in their Staffel, but there was some delay in obtaining the necessary apparatus, notably the "Y" clock, and at the time when P/W were captured on January 23rd, only two or three aircraft of the Staffel were equipped. 28. P/W themselves had received a certain amount of theoretical instruction during January but only one of them - the W/T operator - had seen the "Y" clock. They were to have received airborne instruction on January 25th and 26th flying over the North Sea one northerly course from Leeuwarden; it was thought that the necessary airborne instruction could last about 8-10 days in all and that early in March aircraft of the Staffel would be ready to use the new procedure operationally over the front line areas. 29. The type of "Y" beam station used is described by P/W as a number of main aerial masts about 10-12 metres high interspaced with smaller vertical dipoles which radiate one main beam and a series of about six secondary beams on each side of it at diminishing intervals, the first being at 13° from the main beam. The array is located on a large turntable for directional purposes. P/W stated that two of these "Y" stations were at Leeuwarden and on the mainland near Den Helder respectively. 30. For the reception of the "Y" beam the aircraft carries a FuGe 28, the visual indicator of which is referred to according to circumstances as "Kommando" or "Anzeiger". When the aircraft is flying along the main beam to the target the pointer on the dial gives "Kommando", that is to say when the pointer indicates left it "commands" that a correction to the left must be made to return to the beams. When the aircraft is flying on a secondary beam, however, the pointer is referred to as "Anzeiger" and "indicates" the position of the aircraft in relation to the beams. When the pointer indicates left for instance, the aircraft is to the left of the secondary beam and a correction to the right must be made to bring it back to that beam. 31. The reverse holds good when flying back from the target to base but for convenience the visual indicator can be switched over for the return flight to indicate in the same way as on the outward flight. 32. The continuous tone of the secondary beam is undulating while that of the main beam is level and the difference can be readily distinguished by the W/T operator. It is usual for the aircraft to fly along o secondary beam until instructions are received over the "Y" clock or the FuGe 17 to fly on the main beam. 33. The "Y" clock indicates by means of radio impulses from the ground station a previously-arranged series of code instructions similar to those used in the Egon procedure. Its great advantage is that it dispenses with almost all R/T or W/T signals between ground central and aircraft. 34. P/W did not know the FuGe number of this instrument and none of them, with the exception of the W/T operator, had heard any other name for it than the "Y" clock; the latter had once or twice heard it referred to as the SNK-Gerät, but he had no idea what these initials denoted. 35. The description given by P/W is strikingly similar to that contained in A.D.I.(K) 160/1944 paras. 29-36. Basically the clock consists of a cathode ray tube screen about 20 cm. in diameter with numbers from 0 to 9 spaced at intervals round its circumference. Each of these numbers denotes a code instruction, the significance of which is given on the W/T briefing sheet for each operation and is varied from sortie to sortie. 36. Numbers 1 to 3 or 4 are reserved for the individual aircraft and in explanation of this P/W says that at the most four aircraft would be used as pathfinders proper, whilst other aircraft in the unit would be used to renew the markers and flares laid by these four aircraft, flying probably on Egon or even on D/R to bring them near enough to the original marking to enable them to correct their course themselves. 37. The remaining numbers, i.e. 0 and 4 or 5 to 9, are allocated to the respective code instructions, such as "distance from ground station to aircraft", "distance from aircraft to target", "height", "change course left", "change course right", and bomb release warning. 38. The "hand" of the look appears as a wedge-shaped blip on the screen of the Cathode ray tube about two-thirds out from its centre. It rests at a neutral position at twelve o'clock and is moved to the various figures by means of impulses from the ground station lasting only 1/100th of a second, and therefore calculated by the Germans to be unjammable by us. 39. There is an aerial in a shallow perspex-covered bola in the centre of the underside of the fuselage, but P/W could not describe this array or say whether it was for the "Y" beam reception or for the SNK-Gerät. 40. During its flight the aircraft keeps its FuGe 25a switched on and is plotted by ground Radar, which gives any necessary instructions over the "clock". According to P/W the positions 1 and 2 on the FuGe 25A indicate "Grob-Messung" (coarse fix) and "Fein-Messung" (fine fix) respectively. 41. The method of working with the new "Y" procedure is as follows: The aircraft flies by D/R from its base until it picks up the secondary beam of the "Y" station, along which it then flies until instructions are received to move over to the main beam. The W/T operator has his FuGe 17 switched on ready to receive any instructions, and the FuGe 25A is switched on in position 1. 42. From time to time signals are received from the ground, the warning to the W/T operator being a continuous tone of about 2 - 3 seconds on the FuGe 17 indicating to him that he is to stand by to receive instructions over the clock. Shortly afterwards a small white indicator an the top of the clock lights up and the blip moves round from the neutral position at 12 o'clock to one of the numbers between 1 and 4 indicating the particular aircraft being called. After stopping at the number for a second or two only, the blip returns to the neutral position. 43. The message for the particular aircraft called then begins. If the instruction, for instance, is "change course to the right by 15°", the blip will first move to the number allotted to "Change course right" and then in turn to the numbers 0, 1, 5, indicating 015°, returning to the neutral position after each individual number, Acknowledgment of the message is made by switching the FuGe 25A off and on again. If this is done instructions are continued if necessary, but if no acknowledgment is received by the ground control, the instruction is repeated until acknowledged with the FuGe 25A. 44. Should the aircraft wander owing, for example, to disturbance of the beam, fresh instructions are sent from time to time by means of the clock. Shortly before the target is reached, instructions are received via the "clock" to switch over to position 2 on the FuGe 25A for a fine fix on the last run to the target. 45. One minute before the actual target is reached the W/T operator receives his standby warning on the FuGe 17 followed by the appropriate code number on the clock denoting that the markers or flares must be released in 60 seconds time. The W/T operator or the observer then "stops" this time on his watch, but the flares or markers are not-released until a red lamp lights up above the clock; this may be a little short of 60 seconds or a little longer. 46. The bomb release signal could also be given over the FuGe 17 instead of over the clock. The method in this case would be that at the beginning of the 60 seconds a morse signal such as -. would be given and then when the time of release was reached a further -. , the flares being released on the final dot. 47. The clock is usually placed in front of the observer so that he can acknowledge signals with the FuGe 25A, which is also situated within his reach. 48. Although two or three aircraft of 1/K.G.66 are at present fitted with SNK, it is the intention to fit all aircraft of the Staffel with this new apparatus. The aircraft retains, however, its normal radio equipment, so that it can operate with either Egon or the new "Y" procedure as required. The aircraft were flown from Dedolstorf to Celle for the fitting of the SNK. FuGe 217. (Radar). 49. The Z6 + FH was fitted with a FuGe 217. The crew had little practical experience with it - they had used it on only one sortie, in the course of which nothing was picked up - and they appear to have had rather inadequate instruction in its function, but they were able to give the following description of the apparatus. 50. The FuGe 217 differs from the FuGe 216 in both the display and the aerials. In the FuGe 217 the display is horizontal across the middle of the screen and through the centre of it runs a vertical white line which represents zero. The return from the aircraft itself shows on both sides of this middle white line, whilst the blip from the enemy aircraft shows on one side or the other. 51. The range runs to both left and right, with an extreme on either side of 8 km. The exact object of ranging from the middle is not known to P/W and they can only suggest that it may be to indicate whether the aircraft approaching from the rear is to the left or right. 52. The W/T operator states that the crew had had this apparatus explained to them merely as equipment for searching to the rear and had never heard of it in connection with D/F'ing, although having a vertical line in the centre of the screen with display on both sides of it would indicate that perhaps it could be used for this purpose. 53. Although the screen is calibrated up to 8 km, the actual maximum range at K.G.66's normal operational height - some 2000 metres - is only about 4 km, as this is the distance on the display between the return from the parent aircraft and the ground return; the observer assumes that the minimum range at which an aircraft can be identified is about 500 metres, but it may be a little less. 54. Below the screen are three control knobs for focus, brilliance and range; the latter has two positions, one for a coarse setting giving the 8 km, range, and the other a fine setting for a range of 4 km. 55. There is an aerial array above each wing surface; that on the starboard wing, P/W believes, is the transmitter, and that on the port wing the receiver. The main support for each array protrudes rearward from the wing surface at an angle of about 35° from the horizontal, at a point about a quarter of the way inboard from the wingtip and just forward of the aileron. 56. Running upwards from the main support, at a slight angle to the vertical, are three feeders, each with a horizontal dipole at its tip, extending about 15 cm. to either side of the feeder. The feeders are staggered in length, the forward one being highest and the aft one lowest; the latter is almost directly over the trailing edge of the wing. 57. During lectures on FuGe 217, the instructor had drawn the lobe of search and P/W says that whereas in the FuGe 216 this was to the rear and downwards, in the FuGe 217 it was to the rear and above the aircraft, with the deepest point only some 400 metres below the aircraft itself. 58. The explanation of this may be that the operations carried out by K.G.66 were mainly those entailing a low flying height - anything from ground level up to 2000 metres - and therefore any contact by night fighters would be free the rear above rather than below. The angle of search is about 30° from the centre on each side, and there is a small lobe of search, probably about 1 km, to the front of the aircraft. 59. Crews are not enthusiastic about the FuGe 217 and the present one, although it had been flying several months with it, had only once used it on one sortie, mainly because when they switched it on it disturbed the whole of the radio equipment in the aircraft. Not only the intercom, but also ground signals over the FuGe 17 or FuGe 10 are upset, and it also makes D/F'ing extremely difficult. Apart from this, P/W also believe that the radiations facilitate the work of our airborne search equipment. JU.88 S-3. 60. The Z6 + FH, a Ju.88 S-3, was fitted with Jumo 213 engines. The crew are very enthusiastic about this aircraft and state that with the Jumo 213's it has the following speeds at about 2000 metres:- 2300 r.p.m............ 380 k.p.h. A.S.I. without bombs. 370 k.p.h. " with bombs. 2400 r.p.m............ 390 k.p.h. " without bombs. 380 k.p.h. " with bombs. 2700 r.p.m.(highest... 440 k.p.h. " without bombs. cruising speed) 430 k.p.h. " with bombs 61. They themselves had never exceeded 440 k.p.h. and in fast they usually flew with 2300 r.p.m. The rate of climb was stated to be 8 metres per second with bombs at 270-280 k.p.h. A.S.I. and 15 metres per second without bombs at 240-250 k.p.h. PERSONALITIES - 1/K.G.66. 62. Oberleutnant HANSEN is Technical Officer of the Gruppe. 63. 1st Staffel. Staffelkapitän Oberleutnant PIOTA. Ia.(Operations Officer) Oberleutnant HEBERSTREIT. N.O.(Signals Officer) Leutnant KUBLER. 64. The following are crews in the 1st Staffel:- Pilot: Oberleutnant PIOTA. Leutnant ALTROGGER. Observer: Unteroffizier SEMPF. Feldwebel HERMANN. W/T: Unteroffizier KONNER. Oberfähnrich GRAUENHORST. Pilot: Leutnant KUBLER. Oberleutnant TRAUBER. Observer: Feldwebel MALLY. Fähnrich SCHNEIDER. W/T: Unteroffizier SCHMIDT. Feldwebel BEHRENS. Pilot: Stabsfeldwebel FISCHER. Feldwebel HOFSTELLER. Observer: Oberleutnant HEBERSTREIT. Unteroffizier VOGEL. W/T: Stabsfeldwebel BACHMANN. Feldwebel NIED, Pilot: Oberfeldwebel JACOBS. Unteroffizier KELLER. Observer: Oberfeldwebel JAGLA. Unteroffizier SCHONFELD. W/T: Unteroffizier BINGEL. Unteroffizier SILKE. 65. Stabsfeldwebel FISCHER, who pilots Oberleutnant HEBERSTREIT the IA of the Gruppe, is in the Stabstaffel but is attached to the 1st Staffel. 66. Oberfeldwebel LEHR, a pilot in the Staffel, has gone off to the Luftkriegschule and will shortly be returning as a Leutnant. His W/T operator Feldwebel TOMASCHEK is at present without a crew. 67. Oberfeldwebel SIEMER has left the 1st Staffel and is now in the Kriegsschule; it is not known if he will return to the Staffel. 68. Apart from the above, three new crews with an Oberleutnant, an Oberfeldwebel and an Unteroffizier as pilots, names unknown, arrived a few days before the present crew was shot down. 2nd Staffel. 69. The following are pilots in the 2nd Staffel:- Oberleutnant GUSZ. Oberleutnant MADETZKI. Unteroffizier ROTGANGEL. Feldwebel ROTH. 70. Oberleutnant GUSZ is the Staffelkapitän; his observer is Unteroffizier ULLRICH. 3rd Staffel. 71. The following are members of the 3rd Staffel:- Pilot: Leutnant BERCHTOLD. Observer: Unteroffizier GRUNEL. W/T: Oberfeldwebel KURZ. Pilot: Oberleutnant MEHLS. " Leutnant HINZ. " Gefreiter KANDZORA. Losses. 72. The following were lost during the operations over the Bastogne pocket:— 1st Staffel - Oberfeldwebel SCHMALZBAUER. 3rd Staffel - Fähnrich TULLNER. Oberfeldwebel MOTZ. Leutnant SCHUBERT. 73. The W/T Operator of the last named was Feldwebel LABINSKI. K. G. 54. 74. It has been stated earlier in this report that prior to joining K.G.66 this crew, had been in II/K.G.54. In December 1944 one of them met a friend from his old unit who told him that II/K.G.54 was in process of converting to the Ar.234. Unfortunately, no further details were available. A.D.I.(K)& U.S. Air Interrogation. S.D. Felkin, 19th February 1945. Wing Commander." Bruce |
Re: Using Ultra to research the Luftwaffe
"SECRET A.D.I.(K) Report No.187/1944
THE FOLLOWING INFORMATION HAS BEEN OBTAINED FROM P/W. AS THE STATEMENTS MADE HAVE NOT AS YET BEEN VERIFIED, NO MENTION OF THEM SHOULD BE MADE IN INTELLIGENCE SUMMARIES OF COMMAND OR LOWER FORMATIONS, NOR SHOULD THEY BE ACCEPTED AS FACT UNTIL COMMENTED ON IN AIR MINISTRY INTELLIGENCE SUMMARIES OR SPECIAL COMMUNICATIONS. SOME FURTHER NOTES ON G.A.F. PATHFINDER PROCEDURE. 1. Since the issue of A.D.I.(K) Report N°160/151,4, "A G.A.F. Pathfinder Unit", the two P/W concerned have added some further details of the Egon procedure. This information, together with some notes on other navigational aids, is summarised in the present report. EGON PROCEDURE Operation 2. It was stated to be usual for five or six aircraft from 5/K.G.66, using the Egon procedure, to take part in a pathfinder operation. Whilst some of these would be engaged in laying the turning point markers, others, all controlled on one and the same frequency, would be flying at intervals to the target to place and renew the target marking. 3. According to P/W, although one Freya would suffice for the Egon procedure, two plotting Freyas are employed so that the second can give undivided attention to the aircraft which is near and over the target, whilst the first Freya plots the aircraft up to that point. 4. When a pathfinder aircraft has released its first flares it is usual for it to make a 180° left-hand turn and fly away from the target, leaving its bomb-doors open and maintaining the same height as at the time of flare release; a further turn of 180° then brings the aircraft back to its original course for the second run-in. 5. Freya control is maintained during this manoeuvre and course corrections are given if necessary; should the aircraft be in the correct position for the bombing run, the only signals from control are those for pre-release (dash) and for release (dot). It is stated that the latter signal may consist of either one or three dots. 6. It frequently occurs that aircraft which have placed the turning-point markers also proceed to the target area to help in renewing the marker flares. In such cases the aircraft are given new courses by control immediately after completion of the turning-point marking; the initial new course is indicated in this case in degrees, e.g.: "Autobahn 128". 7. Freya control of any aircraft ceases immediately after the completion of the task of that particular aircraft. Range and Accuracy 8. The present Egon procedure is operable up to a range of approximately 270 km. P/W amplified his previous statement on the accuracy of the present Egon procedure and stated that he had been told it was accurate to 0.3 degrees in bearing and 200/250 metres in range. Communication with Aircraft 9. The P/W from the Z6+IN was able to add further code words and their meanings to the list given is paragraph 20 of A.D.I.(K) 160/1944.- W/T R/T Meaning 3 letter code group Zeppelin Originally (Rübezahl) Codes used for "control" ...--... Frage Question (precedes a codeword if a question is asked MAR Marie Your distance in min- (followed by a number) utes from base is ... NTE Ente Your distance from (followed by a number) the target is ... SNK Schnecke (=snail) decrease speed EXP Express increase speed KRS Karussel (=merry-goround) Fly in circle REI Reise Reise Fly on as at present NAL 1 Kanal 1 NAL 2 Kanal 2 (The keyed (morse (recognition) and un- (Keyed signals (respectively of the (FuGe 25A. CCC Caruso No more evasive action to be taken from now (prior to bomb release signal) AAAMAT+/+ Autobahn+/+ Heimat Set course for base VVV Victor understood SAL Trübsal Have you enough fuel (followed by a number) for....minutes flying KKK Ich besuche Sie or Ich besuche Sie nicht mehr, bitte kommen you are being plotted or control finished, please confirm +/+ = amendment to previous list. 10. The signals "Schnecke" and "Express" are given by control when the aircraft in ahead of or behind schedule. When control sees that the aircraft will arrive too early, "Schnecke", followed by a number is signalled, meaning "at your present speed you will arrive...... minutes too soon over the target". "Express" is given for the opposite condition. 11. Before the pathfinder aircraft has been released by control the only communication from the aircraft to control is normally by manipulation of the FuGe 25A switch, although if specially requested the aircraft will resort to R/T or W/T. Control frames questions to the aircraft in such a way that they only require an acknowledgement and can therefore be answered by means of the FuGe 25A. 12. The FuGe 25A is switched to Kanal 1 to transmit the morse recognition signal and to Kanal 2 for the unkeyed tone signal. Kanal 1 is employed until the aircraft is within 50 km of the target, Kanal 2 being used whilst the aircraft is near and over the target and under control of Freya No.2. The latter Kanal enables the bearing of the aircraft to be read more accurately. 13. Each signal passed by control to the aircraft must be acknowledged on the FuGe 25A, either on Kanal 1 or 2. In practice, however, crews often forget to acknowledge signals and control therefore requests "Kanal Quittung" and awaits the appropriate reply. 14. When control of an aircraft is being withdrawn, control signals "Ich besuche Sie nicht mehr, bitte kommen" (I have finished with you, please confirm). Communication Frequencies 15. As an example of R/T and W/T frequencies employed on a pathfinder operation, P/W quoted those used on the night of 24/25th March 1944. These were 40.5 mc/s on FuGe 16 and 4848 kc/s on FuGe 10, besides the 583 kcs of the broadcasting station Calais I. New Egon Procedure 16. It was stated that certain crews of 5/K.G. 66 had been sent to Königsberg/Neumark for practice with the new Egon procedure. 17. whilst P/W had little to add to his original description of the Egon attachment which will be introduced into operations at some future date, he believed that the presentation apparatus of the ground-control equipment is divided up into sectors in a similar manner to the airborne apparatus. 18. He did not know details of the frequency, other than that it is V.H.F. and crystal controlled. OTHER NAVIGATIONAL AIDS Bernhardiner Gerät 19. The present P/W were able to add a few small details on this subject to those given in A.D I.(K) 108/1944 paragraphs 37 - 39. 20. In October 1943, 5/K.G. 66 had a Do. 217M equipped with the Bernhardiner Gerät, manufactured by Telefunken. Oberleutnant Grotz and a civilian technician named Menzel or Wenzel conducted some experiments but came to the conclusion that the apparatus was not sufficiently accurate for pathfinder work. It was thought to be accurate enough for the use of bomber units, however, and at that time it was proposed to pass the equipment over to K.G. 6. 21. P/W later overheard the Gruppenkommandeur saying that the project might have been abandoned as work on the ground installations had ceased. 22. One Bernhard (ground station) was known to P/W near Chartres; the apparatus was about 30 metres high and was mounted on a turntable some 40 metres in diameter. Each ground transmitter was to work on a different frequency so that dross bearings could be taken. 23. The aircraft equipment included a Hellschreiber (teleprinter) some 40 cm. square. A paper tape appeared in a window of about 30 cm. in length in the front panel, and every 30 to 60 seconds the true bearing of the aircraft and the time of the bearing appeared on the tape. This equipment, which was thought by P/W to work through the E.B.L.3., is remarkably reminiscent of the Drehelektra described by P/W of the old Gruppe 106 in May 1942 (A.D.I.(K) 104/1942 paragraphs 8 - 15) and later by other P/W of the same unit (A.D.I.(K) 244/1942 paragraphs 11 - 16). 24. The range of the Bernhard was said to have been about 400 km. under ideal conditions. Erika Gerät 25. Experiments in this navigational aid were conducted in K.G. 66 under the direction of a civilian technician by the name of Voss. The system was abandoned as being too open to enemy countermeasure, and the instruments were withdrawn from the unit. P/W knew no details of how the Erika Gerät functioned. Y-Gerät 26. P/W stated that 1/K.G. 66 used the 'Y' system as a navigational aid; he had seen the switch for the FuGe. 28A in one of the aircraft of that Staffel. "X" Clock 27. Early in 1943 P/W saw a number of "X" clocks, of both the larger and the new smaller types, in the technical section of the Staffel. He understood that these were to be employed in conjunction with Hohentwiel for attacking ships. He had heard nothing more of this, however, and recently the "X" clocks were no not to be seen. Jamming of Knickebein 28. One of the present P/W stated that it was possible for an experienced operator to read through British jamming of Knickebein; he said that the genuine dots and dashes were more pronounced than those produced by the countermeasures. 29. Another type of interference which P/W had experienced with Knickebein took the form of rising and falling wail. German Jamming of R/T 30. P/W could not enlarge on his previous account of the activities of 3/K.G.66, to which he was attached for six months at Cormeilles-en-Vexin, since during that period the Staffel was still only under training for investigation and countermeasure flights. He stated, however, that the aircraft were equipped with a fixed wire aerial about 1.20 metres in length fitted under the fuselage, and he believed that this aerial was used in conjunction with the Viktor R/T jamming set. A.D.I.(K) S. D. Felkin 25/Apr/44 Wing Commander" |
Re: Using Ultra to research the Luftwaffe
Amazing.
|
Re: Using Ultra to research the Luftwaffe
Quote:
Other thoughts: (1) Bruce has done me a great service, at least — my microfilm print-out of No. 160/1944 is almost impossible to read, now I finally know what it says! (2) If you're interested in the last flight of Z6+FH, on what was a busy night over Holland and Belgium, there's this http://www.ghostbombers.com/kf4/West/zeisig1.html and this http://www.ghostbombers.com/Olga/map23jan.html |
Re: Using Ultra to research the Luftwaffe
Quote:
Best regards, Marcel (I./KG66 Research) |
Re: Using Ultra to research the Luftwaffe
Very interesting reading. Thanks for that.
Paragraph #74 of post #178 is probably responsable for the rumor that initially KG 54 was to convert to the Ar 234 in stead of the Me 262. Quote:
|
Re: Using Ultra to research the Luftwaffe
[quote=Nick Beale;259922]Agreed, would people like a dedicated "Researching the Luftwaffe through Prisoner Interrogations" thread?
QUOTE] Hi Nick, Yes what a wonderful idea. bregds SES |
Re: Using Ultra to research the Luftwaffe
Quote:
PS: Is your website down at the moment? I tried to read the info from the links you provided, but couldn't get on your site. Best regards, Marcel |
Re: Using Ultra to research the Luftwaffe
Quote:
Nick, I look forward to following whatever course you decide on. For the record, within these P/W reports are references to 'captured documents': I hope everyone recognizes that this meant ULTRA or another sensitive source that could not be named at the time, hence my choice of the 'Using ULTRA...' thread for posting. Bruce |
Kg40 in item 37
"SECRET A. D. I. (K) Report No. 357/1945.
THE FOLLOWING INFORMATION HAS BEEN OBTAINED FROM P/W. AS THE STATEMENTS MADE HAVE NOT AS YET BEEN VERIFIED, NO MENTION OF THEM. SHOULD BE MADE IN INTELLIGENCE SUMMARIES OF COMMANDS OR LOWER FORMATIONS, NOR SHOULD THEY BE ACCEPTED AS FACTS UNTIL COMMENTED ON IN AIR MINISTRY INTELLIGENCE SUMMARIES OR SPECIAL COMMUNICATIONS. RADIO AND RADAR EQUIPMENT IN THE LUFTWAFFE - II Navigational Aids. 1. This report is the second of the series dealing with radio and radar equipment in the Luftwaffe. 2. As in the case of the first of the series (A.D.I.(K) 343/1945) dealing with Blind Landing and Airborne Communications Equipment, it is based on interrogation of General Nachrichtenführer MARTINI, Director General of G.A.F. Signals, and a few important members of his staff, and has been supported by a file of current papers which were in the possession of the General’s Chief of Staff. 3. An index of the numerical designations of the navigational equipment mentioned in this report appears in Appendix I. 4. For convenient reference, a translation of the document entitled "Funkausrüstung der Flugzeugmuster, Notprogramm" (signal Equipment in the G.A.F. - Emergency Program) - item 45/99 ff in A.D.I.(K) Documents List 45/9 - which has also appeared as an Appendix to A.D.I.(K) 343/1945, is reproduced as Appendix II to the present report but the list of equipment contained in that document has been omitted as Appendix I gives a fuller list. TRENDS OF DEVELOPMENT. 5. Throughout the course of the war, the general standard of German navigational training was undoubtedly inferior to that of the Allies. A simple form of navigation was taught but navigators track plotted only and relied on W/T aids and in particular positioning by means of loop fixes as the main basis for their navigation. 6. During the early part of the war extensive use was made of Knickebein and other beam systems, but later this form of navigational aid gave way to the "Y" control system (better known by the Allied codeword Benito) and "Egon". 7. Sonne was universally accepted as an outstanding success and from the time of its inception in 1942 research was continuously directed towards overcoming its imperfection, in particular the range limitation. Komet was a typical example, of attempted improvement on these lines 8. The Germans were patently backward in the field of pulse systems and the majority - if not all - of their navigational aids of this type were copied from Allied methods. 9. The fear of the Allied countermeasures was much to the fore during the last two years and considerable research and efforts was devoted to offsetting such interference and to perfecting systems which would reduce and if possible preclude the danger of jamming. Another factor always present in the minds of those responsible for tactical navigational requirements was that the apparatus must be as light and small as possible because of the limited space available in German aircraft. 10. During the last stages of the war, and as a natural consequence of German air policy, being forced to concentrate on the defensive, thereby involving almost exclusive use of fighter power, a great deal of attention was devoted to the development of simple navigational aids suitable for single-engine aircraft of which Rübezahl was a typical example. D/F LOOP EQUIPMENT. PeGe (Peil Gerät) 6. 11. PeGe 6 was the successor of PeGe 5, the standard loop D/F, set in use at the beginning of the war, and. operated on 150 - 1200 kc/s (2000-250 meters). It provided automatic D/F facilities, the W/T operator merely having to tune to the signal and the "answer" being produced on a course indicator. 12. In the opinion of P/W, who was responsible for operational requirements in the navigational field and who had had fairly extensive navigational experience with K.G.40, PeGe 6 was less reliable than the manually-operated PeGe 5 as the automatic D/F facilities could not distinguish between the true signal and jamming and were apt to record bearing midway between the two if they were near together. The human ear was much more acute and could distinguish the minimum of the real signal from that of the "phoney” one. It had the further disadvantage that it was a heavier piece of equipment than the manually operated set. FuGe 141 13. The FuGe 141 operating on a frequency band of 58.0 - 59.2 mc/s was a receiver with a D/F loop fitted to Air Rescue aircraft used for homing on to the NS 4 emergency radio set carried on the chest by pilots. 14. The NS 4 had a flexible steel tape aerial and batteries which gave it an endurance of 2 to 2,5 hours. FuGe 142. 15. The FuGe 142 using the 2000 - 250 metre band was a small D/F battery set for use in emergency in the event of failure of the aircraft' s electricity supply. 16. The FuGe 142 had a manually-operated loop and its accuracy was only 10° to 15°. 17. When the P/W who, in October 1944, took over the navigational tactical requirements first made its acquaintance, he discovered that the designer of the emergency set, while having the laudable object of assisting a crew in dire emergency when they where probably well and truly lost, had omitted to include any sensing arrangement. The set was, therefore, quickly scrapped as being as much of a danger as an aid. FuGe 145 18. The FuGe 145 was a simple type of D/F set in development for use in single-seater aircraft. It was for use with M/F beacons and was designed for use by coastal reconnaissance aircraft, as for example the Do.335, so that they could obtain a bearing when flying at low level. 19. It was much lighter than the PeGe 6 and had no automatic facilities, but was very easy to operate. P/W had thought that it might ultimately supersede the PeGe 6 for other types of aircraft. Suggested loop for fighter aircraft 20. The research centre at Rechlin had been asked to examine a rough type of loop for singleseater fighter aircraft, which would consist of a loop built into the pilot' s helmet. It was thought that this would enable the pilot to establish the general direction of a beacon by movements of his head and without recourse to the use of a compass. 21. This idea was tried out and seemed promising, but was never fully developed. HOMING BEACONS. Schwanboje. 22. The Schwanboje was a waterborne V.H.F. beacon dropped by parachute and originally used by K.G.40 for marking convoys or submarines. In the autumn of 1944 a 1ine of Schwan buoys was used to aid the He.111's when launching V-1’s from the North Sea against this country. 23. The beacon consisted of a frame aerial and transmitted on a wavelength which could be homed on by the FuGe 17, the standard equipment of K.G.40 in 1942 when the Schwanboje came into use. 24. The set was powered by accumulators and had a live of five hours; by the means of a clockwork device it could be pre-set before release so that it ran for a testing period immediately on release and later started up again after a prescribed interval governed by the expected time of arrival of the homing aircraft. The buoy was fitted with a self-destroying charge operated automatically. 25. A later type of Schwanboje operated on the 38 - 42 mc/s waveband so that aircraft equipped with the FuGe 162 could also use the system. Biene 26. Biene is the code word for a responder beacon. The idea of responder beacons for homing purposes had only been hit on in 1944 and Bienen to respond to the different airborne radar sets were still under development in 1945. The FuGe 243 - Hohentwiel Biene – had been used by coastal units in Norway, in February or March 1945. 27. Responder beacons were also being developed for use in the Baldur method of navigation (see paragraphs 79, 82 of this report). BEAM SYSTEMS. Zyklop. 28. This was the latest form of the well-known Knickebein working on 30 - 33,3 mc/s and received by E.B.L.3 in the aircraft. It was a mobile station which could be fully erected into operation within a week. 29. A still more mobile unit known as the Bock-Zyklop had been introduced. This could be set up in three days and could be adapted for use on the FuGe 16 frequency although as yet, according to documents, no visual indicator for the FuGe 16 had been developed. 30. The 120 W ground transmitter was called the ???? which gave a beam 0.5° wide and a range of 300 km. at a height of 5,000 meters. The Zyklop systems had been made use of on the Russian front up to the end of the hostilities. Sonne. 31. The Sonne beacon system which worked on a frequency of 270 - 480 kc/s was received in the aircraft on the FuGe 10. It was considered an extremely effective daylight system but the range limitation was a disadvantage. Fixes could be obtained from ranges up to 1,000 - 1,200 km. Sonne 6 at Quimper which was the most efficient of the Sonne beacons, had been used on an occasion at a distance of 1,400 km. 32. The sectors served by Sonne covered, an angle of 120 – 150°. The beacon was very reliable over the centre sector of 100°, but the error increased progressively towards the edges of the beam in conformity with the sine law. 33. At night errors up to 4° were liable to occur even in the centre of the sector of the beacon and no real use could be made of it. Mond. 34. To improve the Sonne beacons both in range, and accuracy, an experimental system working on the same principle, but on 3000/6000 kc/s was tried out in 1942. The shorter wave transmission did not prove very reliable and was given up about the end of 1943. Stern. 35. Finally a beacon of the Sonne type under the name "Stern" was designed for use on a V.H. frequency. It, not unnaturally, only gave optical range and was, therefore, of no practical value and was not developed. Dora. 36. One P/W had seen documentary mention of Dora which he believed was a navigational aid system and a precursor of Komet. He did not know whether it worked on the same principle but the Komet experimental site at Kolby was on the former Dora site. Komet. 37. In 1942 the question of navigation over the Atlantic stood in the limelight . As the He 177 was supposed to be coming into service shortly to enable K.G.40 to reach further West, the need for navigational equipment of longer range became acute. 38. A year or so earlier Professor von HANDEL had categorically stated in a lecture that a long-range navigational system based on pulse would inevitably be extremely inaccurate. In view of Professor von HANDEL's views on pulse systems, an improved form of Sonne which would give much greater ranges and be less susceptible to night effect was given high priority. 39. The system evolved was called "Komet" and experimental stations were erected at Bordeaux and Kolby (see A.D.I.(K) 364/1944). The ground station called for an array of no less than 127 masts and 19 control huts in order to cover a 90° sector. It worked admirably provided a 10° sector only was covered, but as soon as the planned 90° sector was put into operation, mutual interference between the masts arose and the various lobes radiated were no longer of symmetrical pattern, with the result that large errors crept in. 40. Research on this delayed the project considerably. After the invasion when long distance reconnaissance in the Atlantic was no longer practical politics, the Komet system was given up without ever having been effectively used. The development people were the more pleased to dispense with it since it left the German radio research and industry free to deal with other more urgent matters. 41. The beacon was to operate on frequencies of 5000, 9000 or 12,000 kc/s received on the FuGe 10K, and it was estimated that ranges up to 3000 km would be obtained. The system employed was to be similar to that used in the Sonne but instead of obtaining one reading per minute, oscillation of the beam was to be speeded up to give 100 readings par minute. 42. The true bearing of the aircraft was automatically recorded by the FuGe 124 which was known as the Kometschreiber. The recording took the form of a series of vertical lines, one for each reading, printed on a strip of paper. At the same time as the lines were printed the Kometschreiber recorded the section of the swept area in which the aircraft was flying, thus giving what amounted to a rough position. 43. The fine reading was obtained from the length of the recorded lines. Any inaccuracies due to night effect could be easily eliminated by averaging the length of the lines, as recorded, on the paper strip, by eye. Erika. 44. Erika was a navigation system (see A.D.I.(K) 364 and 409/1944.) which had already reached the development stage in 1942 but its operational employment was of brief duration and it was soon discarded in favour of Bernhard. 45. Erika was based on the principle of a V.H.F. (30 - 33 mc/s) beam oscillating rapidly over a segment of about 60 – 90°. The beam was phased, a different phase being picked up in different sections of the segment and read off in relation to a standard phase producer in the aircraft. In order to obtain a fix, two such Erika stations had to be received and to receive each station no less than two E.B.L.3's were necessary making a total of four receivers. 46. The range presentation unit in the aircraft, FuGe 121, took the form of a clock-face with a needle indicator and calibrated, P/W thought, from 0 -100. A specially prepared map was required to establish bearing. 47. A disadvantage of Erika was the vulnerability to jamming, interference signals modifying the phase and thereby giving inaccurate readings. The great weight, carried and the bulk of the four receivers, which were particularly cumbersome in the relatively small aircraft in use in the G.A.F. made its widespread use impracticable. Bernhardine. 48. This system was first introduced in 1942 for use by bomber aircraft, but was later dropped in favour of the Benito and Egon control systems. With the increasing British jamming during night raids it was reintroduced for use in night fighter commentary (see A.D.I.(K) 125/1945, paras.5 to 29), which it was thought could only be jammed with great difficulty. 49. The term “Bernhard” was used for the ground stations whilst the airborne recording equipment was called Bernhardine or FuGe 120. The latter made use of the E.B.L.3. receiver as the transmissions lay in the 30-33 mc/s band. 50. At the time of the German capitulation, the following three transmitting stations were in operation, the first two, of which could transmit commentary.- -Thisted, on N.W. coast of Denmark. -Bretstedt, N. of Husum, Germany. -Trebbin, S.E. of Berlin. 51. A further station near Breslau had been almost completed when it had to be dismantled on account of the Russian advance. Additional stations were in the course of construction near Kassel, Munich, Pilsen and Vienna. 52. The Bernhardine system was looked upon as a considerable improvement on Erika. It gave 360° coverage as compared to 60/90° with Erika and, whereas from the jamming aspect stray signals could disturb the phase of Erika causing false indication, in the case of Bernhardine, interference merely resulted in no reading being possible, and furthermore to attain this through 360° a very powerful jamming transmitter flying near the ground station would be needed. 53. The Bernhardine system was not regarded as unjammable but it was thought that use of high power and aerial gain would render jamming by airborne means impracticable. 54. In addition to the E.B.L.3 receiver, the airborne Hellschreiber FuGe 120, also called the Bernhardine, which gave both bearing and commentary was employed. According to P/W the FuGe 120 was large and weighty and the first improvement aimed at was to reduce the weight and provide a set which occupied less space in the aircraft. To this end an attempt was made to eliminate the use of paper strip for the Hellschreiber and a rotating "Folienschreiber" a cellophane paper moving over a sticky carbon surface which constituted a self-eraser - was employed. This projected recording method proved a failure and the use of paper strip had to be reverted to. According to documents the type using paper strip was known as FuGe 120a, and the self-erasing recorder FuGe 120b. 55. A smaller model, the FuGe 120k, to operate on the paper strip principle which constituted the latest improvement, was still in the development stage at the conclusion of hostilities. Previously the ground transmitter broadcast simultaneously from the upper and lower aerial arrays on two frequencies close enough to one another for them both to be received on one channel of the E.B.L.3. One lobe was used for coarse D/F, the other for fine. The two frequencies were then separated by a filter before being fed into the Hellschreiber. The FuGe 120k was designed for use with a ground transmitter operating only on the coarse D/F frequency. The filter could therefore be dispensed with and considerable weight saved in the airborne set at the expense of some accuracy in D/F. 56. With the loss of D/F accuracy the sharp “V” in the vertical printing indicating the reading (see diagram A.D.I.(K) 125/1945 para.18) became a gap about 4° wide. To facilitate the reading of the centre of the gap by eye, and to reduce the size and weight of the apparatus, the vertical lines referred to above were superimposed on the scale which could then only be read in the gap. This allowed the paper strip to be considerably narrower. 57. The FuGe 120k was designed primarily for use in single seat jet aircraft but was also to be embodied in the Ju.88 where space was at a premium, as soon as sufficient numbers of this set were available. Hermine. 58. The Hermine system was originally developed, in response to a tactical requirement formulated during the second part of 1942, as a navigational aid for the purpose of giving an approximate bearing to single-engine night fighters engaged on “Wilde Sau” operations. 59. By the time the initial difficulties in development had been overcome Wilde Sau night fighting had almost ceased; it was found however that Hermine could be used to advantage by day fighters, and it came into operational use. 60. An accuracy of ±5° was assumed, but it was found in practice that this could be improved upon to ±3° by experienced pilots. 61. Thirteen or fourteen ground stations were in operation by Easter 1945 which, P/W claimed, gave complete coverage of the Reich. It was intended to fit two Schlechtwetter (bad weather) Fighter Geschwader with the necessary airborne equipment, and this program had been onethird completed by May 1945. One P/W had heard that ten to fifteen Me.262's of K.G.51 were amongst the aircraft so equipped. 62. The following may be added in modification of the description of the Hermine system given in A.D.I.(K) 125/1945, paras.59 to 62. The Hermine rotating beacon transmits a continuous tone on which is superimposed a speaking clock which counts from 1 to 35, each figure representing tens of degree. Over an angle of about 15° the continuous tone falls to a minimum and rises again. During this period the voice appears to become more audible and the pilot can estimate where the minimum of continuous tone occurs, and so obtain his bearing from the beacon. 63. The beacon recognition is given by means of a self-evident code name for example, "Berolina” for Berlin – which is spoken by the voice in place of 000°. 64. The airborne equipment is the FuGe 125 consisting of the E.B.L.3 with the Tzg (Telephoniezusatzgerät) which enables the 30.0 - 33.3 mc/s transmission picked up on the E.B.L.3 receiver to be heard in the pilot's headphones. Though the Hermine beacons were fully operational there was a scarcity of FuGe 125 sets, as a result of which practical experience of this system was too limited to judge of its efficiency or to lead to further improved tactical requirements been formulated. PULSE SYSTEM. Ingolstadt 65. All the P/W had heard reference to Ingolstadt and agreed that it was a long-range navigational system. 66. One P/W thought that Ingolstadt was the cover name for a pulse navigation system using hyperbolic curves and similar to British Gee; it was originated by Telefunken in 1938 but was then turned down by the R.L.M. In his recollection the original Telefunken idea derived from theoretical discussions at an international conference before the war. 67. As mentioned earlier under the heading of Komet, Professor von HANDEL maintained that owing to the incidence of mutual interference between direct and reflected waves the system was impracticable at long range. In consequence of von HANDEL’s view the system was dropped. 68. Much consternation and annoyance was occasioned in 1944, when it was found that the Allies were successfully operating a similar system. 69. Truhe is the cover name used to describe navigational aid system, using ground stations, similar to those of British Gee. In effect the British Gee stations were also used, the airborne sets being almost identical with the British Gee boxes. Truhe. 70. There is no very distinct difference between "Truhe" and "Hyperbel". The latter term was originally coined to denote our Gee. It was also used when German aircraft equipped with British Gee sets made use of British ground stations. 71. The British Gee chain was used successfully but it was realised that so soon as the Germans lost an aircraft, over England, a change would be made. The German "Y" service monitored the British ground stations to follow any change in Gee phasing and passed advice of such change to their aircraft by W/T. 72. Truhe referred to the German system which was ultimately to cover the 20 to 100 mc/s band and employed various types of ground transmitters including Feuerhilfe, Feuerstein, Feuerzange and Feuerland. All these transmitters could also be used to jam our own Gee, further details of which will appear in a subsequent report on German Radio Countermeasures. The original 46 to 50 mc/s system was known as Truhe I and the new 30 to 60 mc/s system as Truhe II. 73. A chain of Truhe stations was built around Berlin, primarily for training purposes and there were in addition groups of ground stations in the Schwarzwald and in Pomerania. The last named was intended for operations against Russia and it is not known if the stations were destroyed before their capture. 74. The airborne sets which were known as FuGe 122 covering 46-50 mc/s and FuGe 123 covering 25-75 mc/s were replicas of the British Gee boxes and according to P/W were equivalent to British R.1324 and R.1355. These German sets were slightly smaller and more compact than the British sets. 75. Truhe was used by F.A.G.2 and K.G.66, but up to the time of capitulation only a few FuGe 122 and FuGe 123 sets had been produced and only one R.F. box for the latter set. Baldur. 76. The Baldur range-measuring system is comparable to the British G.H. and appears to have been imitated from it. It was referred to by P/W as “Egon in reverse" and was the only navigational system developed by the German by means of which an aircraft could measure distance from a known source as opposed to fixing itself by a position line. As the G.A.F. staff were still thinking in terms of a grandiose bomber policy as late as June 1944, it was intended for use by bomber aircraft for pinpointing targets and for accurate blind bombing. 77. The wavelength employed was in the neighbourhood of 2-4 meters and fell in the SN 2 band. 78. Only two experimental transmitters, both located in Lower Silesia, were erected and one P/W maintained that this system never progressed beyond experimental trials by the manufacturers. It was eventually relegated to low priority owing to the virtual cessation of German bomber operations and the pressure of more urgent demands on radio research and the radio industry. 79. The airborne equipment was known as the FuGe 126 which was made up of a transmitter to interrogate a ground responder beacon, a receiver and a presentation unit. The receiver and transmitter were SN 2 units, though P/W thought they might have been slightly modified for use with Baldur. 80. From documents, the presentation unit appears to have been a modification of the Würzburg range measurement tube, and the accuracy is given as ± 100 meters at all ranges, but this was thought to be purely theoretical and P/W doubted whether it would have been possible to achieve this accuracy in actual practice. 81. A smaller airborne set, the FuGe 126k (k = klein = small) was built for use by single-seat aircraft. In reducing the size and weight of the set, and making it pilot-operated, accuracy had to be sacrificed. P/W, who was responsible for putting up the tactical requirements, considered a clock-face presentation to be the ideal solution. It was expected that the accuracy of the FuGe 126k would then be of the order of 500 meters independent of range. Baldur - Truhe 82. It was planned to experiment on a combination of Baldur and Truhe (Gee) for use by bombers. The intention was to use a hyperbolic grid line of Truhe for the target approach. This could be pre-set, and the pilot could fly along it by keeping the blip centralised, and could ascertain his exact position along the line by measuring his distance from a Baldur beacon. This system was considered simpler particularly for a single-seater aircraft, than the method of using two hyperbolic grid lines or two distances from Baldur beacons. The first experimental sets were to be ready in the autumn of this year. Baldur - Bernhardine 83. A further project was a combination of Baldur and Bernhardine to give simultaneous bearing and range. The range indication was to be obtained by the pilot pressing a knob when the range would appear in kilometres on a dial. This system was suggested for use by both day fighters and bombers. GROUND CONTROL SYSTEMS, Benito. 84. The Benito system of control using FuGe 16, known to the Germans as "Y", is too well known to warrant description. The following paragraphs deal with recent developments. 85. When operating the bomber Benito procedure with the narrow beam. (0.3°) essential for azimuth accuracy, it was easy for the bomber pilot to get on to one of the side lobes in error since these were only about 3° from the main beam. 86. In order to minimise the possibility of mistake and to relieve the pilot of the strain of flying on a beam, an automatic device, the FuGe 28a, was in use which was the improved and final form of the old Y-Gerät of 1941. Documents dated about June 1944 show that it was used in conjunction with FuGe 17, but P/W thought that it had been modified for use with FuGe 16ZY as well. 87. The procedure was that the bomber pilot flew on instructions conveyed over the FuGe 17 until it had been established by ground D/F stations that he was on the true beam, when the code word "Bako" would be given whereupon the pilot would switch on the FuGe 28a which took over control of the automatic pilot and kept him on the beam. 88. P/W gave the accuracy of range measurement with the Bomber Benito procedure as only ± 1 km. at maximum range. Egon. 89. The original Egon procedure which involved the use of two Freyas, the one for rough positioning and the other for fine positioning - later became known as "Egon Einstand" (One location) to differentiate from an improved system termed “Egon Zweistand” 90. Egon Zweistand was evolved to offset the inaccuracies in azimuth D/F, and cash in on the range accuracy of radar. With Zweistand a third Freya was introduced, placed some considerable distance from the other two Freyas in order to give a distance cut. It was intended for use by bomber aircraft operating over England or on long range sea missions. 91. The original Zweistand system, which was first tried out in Italy by a Schlacht unit, was somewhat primitive in that the readings from the extra Freya were telephoned through to the plotting centre and worked out before being plotted on the Seeburg table. 92. To eliminate the delay thereby involved a landline connection was introduced to feed the Freya pulse to the C.R.T., which then had two blips showing ranges from the two Freya sites. The vulnerability of landline to disturbance and destruction later led to the development of a W/T transmitter and this method was employed successfully in operations. 93. Since the Freya pulse was not strong enough to trigger off the FuGe 25A at ranges exceeding 250 kilometres, it was planned to supplant the Freya by extra powerful Wassermanns, and thereby increase the effective range of Egon Zweistand to 350 kilometres. 94. A further line of development was the provision of a new type of control table giving the exactitude of plotting necessary for pinpoint bombing. This control table, which was under development at Rechlin, made use of complicated mechanical apparatus for accurate projection of the position of the bomber. One of these tables was destroyed in the course of a daylight air attack on Rechlin in February 1945; two other tables were in existence at the time of the capitulation, and were located somewhere in Western Germany. 95. Egon when first introduced was received with some scepticism by the crews, as it was felt that it was too vulnerable to jamming. After it had been used operationally without being jammed in the attacks on London in March 1944, the procedure was adopted with greater confidence, and it gained a good reputation. As recounted in A.D.I.(K) 343/1945, Egon was always favoured by the R.L.M. technical development section in preference to Benito control. 96. A drawback of the system was its restricted range at low altitude, which according to P/W was the reason why it was not used in conjunction with V.1 operations. Nachtlicht 97. The Nachtlicht system was the first method of control not using R/T speech to be improvised by the Germans, and had been tried out during the raids on London in the spring of 1944. 98. It had been observed that the red signal lamp of the FuGe 25A was illuminated when the aircraft was being swept by a Freya, and it was suggested that use could be made of this as a means of transmitting morse signals from the ground. A Freya operating on a special wavelength, which P/W thought was 2.55 meters, was set up on the Channel coast and was used to send simple instructions to the aircraft attacking London by means of visual morse indications on the lamp of the FuGe 25A. 99. The primitive method of giving distant control indications was the forerunner of "Nachtfee", "Barbara" and "Barbarossa". 100. Luftkurier was the first development of the Nachtlicht idea. It was primitive device intended to give visual indication to the pilot by means of a pointer which was started and stopped by the reception of pulses. 101. P/W thought that Luftkurier was first tried out by K.G.66 on the Freya band, but it was so easy to jam by the addition of extra pulses that it was never developed. Nachtfee 102. Nachtfee was the term used to describe a system for the transmission of control instructions to a pilot in the beam of the controlling Freya through the medium of a C.R.T. indicator similar to the Lichtenstein range tube. The airborne equipment used was known as FuGe 136 and weighed 12 kg. 103. The original purpose of Nachtfee was, to provide a solution to the jamming of R/T control systems, and it had been used operationally by the Pathfinders of K.G.66 for mines in the Scheldt estuary. It was to be adapted for use by night fighters to overcome our jamming of the night fighter commentary. 104. Nachtfee was a system using the FuGe 25A as receiver. 105. The presentation screen in the aircraft was inscribed with various commands both on the inside and outside of a circular time trace. There was a stationary zero blip in the 12 o'clock position, and when an instruction was radiated the pulses received caused a second blip to emerge from the first and travel round the C.R. tube in a clock-wise direction, presumably by a slight change in p.r.f. This blip came to a stop and the command corresponding to its position could be read off on the inside of the time trace where a total of about eight different instructions were inscribed. It took from one to two second, for the blip to travel round the tube. 106. It was thought that the further eight commands inscribed on the outside of the time trace were denoted by the blip making a complete circle starting round a second time before coming to rest at any one of the eight sectors. In this way a total of sixteen different orders could be given. For night fighters such instructions as "turn left/right", "climb", "dive”, etc. appeared on the inner side and figures for transmitting bearing on the outer side of the trace. 107. This system was used operationally, but it was found that, apart from the susceptibility to jamming, other pulse transmissions could interfere by unlocking the system and thereby cause wrong positioning of the indicator blip. 108. Another pronounced objection to the Nachtfee lay in the fact that it was necessary for a member of the crew to watch the C.R.T. indicator uninterruptedly for missing one blip indication might give the message a false value. It was not therefore possible to use it in singleseater aircraft. Barbara 109. This apparatus, also called FuGe 138, consisted of an attachment to the FuGe 25A receiver and only weighed 2 kg. This unit contained an audio filter which allowed the pilot to hear morse signals superimposed on the Freya interrogator transmission if they were emitted on a suitable audio frequency usually about 800 cycles. By keying other morse signals on different audio frequencies and equipping aircraft with suitable filters, more than one aircraft could be controlled by a single Freya. 110. Barbara was to be used for Egon control of ground-strafing aircraft and bombers but not for night fighters. 111. In the Germans' opinion there were three disadvantages, namely that the Allies could intercept and make use of signals so transmitted, that the aircraft had to be in the beam of the Freya if it were to receive, and so an aircraft "lost" by the Freya owing to jamming could not be communicated with and finally that, though intended for single-engined aircraft, fighter pilots rarely had sufficient command of morse to be able to use this type of control. Barbarossa 112. Barbarossa was a set designed to meet the same requirements as Barbara but to remedy two of the drawback mentioned in the last paragraph. 113. The instructions to the aircraft were to be transmitted by code pulse modulations which were passed through a "pulse filter" in the airborne set and a written indication obtained on a Hellschreiber. The pulse filter and Hellschreiber unit were attachments to the FuGe 25A and were known as the FuGe 139. This apparatus was in development at Rechlin under the supervision of Stabs.Ing. von HAUTEVILLE. 114. With this arrangement pulse modulations could not be read by the Allies, and for spoof purposes in order to produce a wrong indication we would have had to know the exact type of modulation accepted by it. Visual indication was also quicker and did not depend on knowledge of morse. 115. This scheme was only in a very early stage of development and P/W were unable to give details. It was hoped that in due course it would be possible to develop matters a stage further and find a means of transmitting scrambled speech instead of morse, but P/W understood that the question of pulse modulation for speech transmission had not been solved. Rübezahl 116. Consideration had been given in 1945 to the introduction of a crude system of navigation which could be only used within the boundaries of the Reich. This was to go under the code name of Rübezahl, and the fact that it was seriously considered and actively supported by the P/W responsible for Navigational Aids on the G.A.F. signals staff is an interesting reflection of the depths to which a combination of Allied jamming under-trained fighter had forced German technique. 117. It was expected that in the course of the summer of 1945 thousands of 162 Volksjäger would be available for the protection of the Fatherland. They were to be equipped with FuGe 24, which was to become the standard G.A.F. R/T set as described in A.D.I.(K) 343/1945. This set did not for the present give Benito control facilities and indeed as they were short-range, high speed, fair-weather aircraft it was not certain that Benito control would be essentially needed. 118. It was essential that their relatively inexperienced pilots should have a simple means by which they could locate their approximate position without any additional navigation equipment having either to be manufactured or carried in the aircraft. It was therefore decided to develop a system which could be used with FuGe 24. 119. In order to direct the Volksjäger pilots to their target, recourse was to be had to the night fighter system of broadcasting a commentary, and this commentary was to be combined with the primitive navigation system Rübezahl. 120. It was therefore planned to set up ground transmitters over Germany at 30 km intervals. The transmitters were to be beamed upwards, so that at 6,000 meters the polar diagram was about 40 km in diameter and lobes from neighbouring transmitters just overlapped, thus covering the whole area. Each transmitter emitted a plain language recognition signal in the form of the name of its district, e.g. Halle, Magdeburg, etc. 121. All transmitters were to be operated on the same frequency so that to locate himself the pilot merely tuned his FuGe 24 to the frequency for the day. The ground transmitters were to be adapted from the FuGe 15 transmitters which had been manufactured in quantity as described in paras. 23-39 of A.D.I.(K) 343/1945 before it was found that the FuGe 15 was unsuitable as an airborne R/T set. They were renamed Bs.15 (Bodensender). 122. Later it was believed that the night fighters which were also to carry FuGe 24 (see appendix 1) would also use the Rübezahl commentary as yet another alternative source for vectoring themselves to the bomber stream." |
Nightfighters radar
"SECRET A. D. I. (K) Report No. 369/1945
THE FOLLOWING INFORMATION HAS BEEN OBTAINED FROM P/W AS THE STATEMENTS HAVE NOT AS YET BEEN VERIFIED, NO MENTION OF THEM SHOULD BE MADE IN INTELLIGENCE SUMMARIES OF COMMANDS OR LOWER FORMATIONS, NOR SHOULD THEY BE ACCEPTED UNTIL COMMENTED ON AIR MINISTRY INTELLIGENCE SUMMARIES OR SPECIAL COMMUNICATIONS. RADIO AND RADAR EQUIPMENT IN THE LUFTWAFFE – VI. Target Homing for Night Fighters. German early warning Ground Radar. 1. This report is the sixth of the series dealing with radio and radar equipment in the Luftwaffe. As in the case of the previous five reports (A.D.I.(K) 343, 357, 362, 363 and 365/1945),it is based on interrogation of General Nachrichtenführer MARTINI, Director General of Signals, and some members of his staff, and has been supported by a number of relevant documents of recent date which were in the possession of the General's Chief of Staff. POLICY AND REQUIREMENTS 2. Members of General MARTINI’s staff have often repeated a catch phrase "Aller Funkverkehr ist Landesverrrat" - all radio traffic is treasonable, and the G.A.F. were only too well aware that a transmission of any type could be listened in to by the Allies and then D/F'd. They were, therefore, fully aware of the opportunities of homing on to transmissions from Allied aircraft and so when airborne countermeasures against the Freya ground installations were first taken by the Allies, Köthen developed an apparatus which would enable a German night fighter to home on to the source of the jamming transmission. 3. This equipment was called Freya-Halbe (Halbe = half signifying that it was a radar apparatus equipped with the receiver half only and not the transmitter), and it was tried out at Werneuchen in early 1943. The trials were successfully completed by about June of that year and it was then demonstrated to the authorities for use by the G.A.F. night fighter units. 4. At that time, however, the German night fighter force was commanded by General KAMMHUBER who was the creator of the Kammhuber line and whose night fighter organisation relied essentially on ground-controlled night fighter aircraft operating in comparatively limited boxes. The suggestion of homing on to jammers was turned down by KAMMHUBER out of hand because he was a rabid opponent of any form of freelance night fighting and insisted on strict adherence by his aircraft to the limits of their box. 5. With the discovery of Monica and the development of the Rosendahl and later the Flensburg homers on to Monica, KAMMUBER still maintained his obstinate stand against any departure from the box system of control. It was, therefore, not until General SCHMIDT assumed the control of the night fighting force in November 1943 and proceeded to introduce freelance methods that D/F homers on to transmissions from the bombers could be used operationally. 6. Although the technical experts were satisfied that the homers on to transmissions of metric wavelengths were successful, aircrews seemed to be unable to use them well and results obtained were never wholly satisfactory. Exactly the same applied to Naxos for homing on to H2S is its early days, particularly when a number of minor troubles were still being encountered with its electrical parts and, though it was available in January 1944, for the first three or four months comparatively little use was made of an excellent homing device. 7. By about Easter 1941 the early troubles of Naxos were overcome and crews began to gain confidence in its use; with the success of Naxos reliance on all types of homing apparatus increased. At this stage, however the R.A.F. had almost ceased to use Monica and Naxos remained the only important set of its type. 8. In view of the change of policy governing night fighter operations experimental D/F receivers known as X-Halbe were designed capable of adaptation to any metric wavelength which might be used by the Allies. In addition one of the tactical requirements laid down after 1943 for all future A.I. sets was that provision should be made for the switching off of the transmitter portion so that the receiver could act as a homer on to any airborne jammers employed by the Allies. Naxos and Korfu Z which covered the 1.5 cm. to 20 cm. band already existed. 9. As R/T and W/T Jamming became more intense and even ground control by commentary broke down, increasing use was made of homing on to the bomber stream by means of receivers of the Naxos type but there remained always the serious disadvantage that these receivers did not supply range. It was claimed that both Naxos and Korfu were so sensitive that the bomber stream could be picked up at a range of 200 km. and that in consequence useless chases often ensued. Estimates of range had to be made by deduction and even in the case of experienced crews the estimate of range by indirect means was not always reliable. 10. Short mention is made below of another form of homing device, the Kiel Z, which attempted to use the infra-red radiations from the exhaust stubs of the bomber. A fuller description of the Kiel Z was given in A.D.I.(K) 390/1945, paras 41 to 48. FREYA-HALBE. 11. The Freya-Halbe, officially known as the FuGe. 221, was designed early in 1943 to home on to airborne Freya jammers but owing to KAMMHUBER's opposition to freelance night fighting was not adopted. Towards the end of 1943 when freelance operations were introduced it was proposed to install the twenty-five Freya-Halbe sets which had been manufactured but, when they were indented for, it was found that the makers had used various parts for manufacturing other apparatus and that the sets had been virtually consumed as spares. Freya- Halbe was, therefore, never used on operations. ROSENDAHL-HALBE. 12. The first Monica set obtained by the Germans was recovered from a British four-engined bomber which was shot down over the town of Rosendahl in Holland and the name of Rosendahl or FuGe. 221.A was then given to the D/F equipment developed for homing on to Monica. 13. According to one of the P/W who had flown the trials with Rosendahl, it was quite successful, and gave good D/F until the night fighter came within 4 km. of its target, after which the D/F became unreliable. For this reason the general introduction of Rosendahl-Halbe was delayed. 14. It was ultimately discovered that the polarisation of the receiver aerials was at 90° to that used by the bombers and it was assumed that this was the cause of the poor D/F. For some technical reason it was not found possible to twist the aerial through 90° in order to obtain the right polarisation and by the time that these difficulties had been overcome the R.A.F. use of Monica had ceased. 15. An interesting experiment was carried out with Rosendahl- Halbe when a set of Rosendahl aerials was mounted round a 150 cm. searchlight. The idea was to align the searchlight beam on to an aircraft transmitting Monica. Considerable difficulty was encountered in getting the searchlight beam and the axis of the receiving lobe to coincide and by the time this had being achieved R.A.F. bombers were no longer using Monica. 16. The Flensburg, officially known as FuGe.227, was another attempt at solving the problem of producing a homer to D/F on to Monica transmission. Difficulty was encountered with D/F properties but the set was satisfactorily selective and could discriminate between a large number of signals by tuning to both the r.f. and p.r.f. It was used to a limited extent in night fighter operations. 17. With the cessation of the use of Monica the original Flensburg became known as Flensburg I and a series of other F1ensburgs, numbered from II to VI, were manufactured to cover the frequencies used by the mandrel screen and other Freya jammers. The frequencies as given in documents were:- Flensburg I 1.3 m. to 1.75 m. against Monica. Flensburg II 1.7 m. to 2.6 m. against Freya A and B band and Jagdschloss jammers. Flensburg III Flensburg IV 2.3 m. to 3.8 m.) against SN 2 and Freya 3.8 m. to 5.0 m.) C frequency jammers. Flensburg V 25 cm, band against 25 cm. P.P.I. ground radar jammers. Flensburg VI 50 cm. band against Würzburg jammers. 18. It was not known to what extent these additional Flensburgs had been used in operations. They were considered to be a successful solution to the homing problem except for the fact that the large aerials, particularly on the Freya frequencies, reduced the speed of the aircraft considerably. A.G.L.T. 19. The interrogation of British prisoners of war had provided information with regard to Village Inn and some details of it were known. It was thought to operate on a centimetre wavelength and pieces of equipment had been found. Nevertheless, P/W were convinced that though preparations for using it had been made it had not yet been employed operationally. X-HALBE. 20. This was the designation of the airborne receiver which could be adapted for D/F'ing any new metric radar that was observed by the monitoring service. NAXOS. 21. The Naxos, known as the FuGe.350, was a detector set which received all transmissions on the 8 to 12 cm, band but could not discriminate between different wavelengths in the band. 22. The problem of producing a homer on to a beamed transmission rotating at 60 r.p.m., as in the case of H2S, was first tackled in March 1943, some two months after the discovery of H2S. Little progress was made until an engineer hit on the idea of getting continuous presentation of the signals received by employing aerials rotating about twenty times faster than those of the transmitter. The G.A.F. signals staff were so impressed with the ease with which it was possible to home on to a slowly rotating beam such as that of the H2S that one of the requirements for the Berlin A was that its rate of rotation in searching should be very high to ensure that the Naxos solution to the homing problem could not be employed against it. 23. The first trials with the Naxos were flown in December 1943 at Werneuchen and the first operational Gruppe to be equipped with the set had it installed in all their aircraft by the 25th January 1944. 24. A whole series of Naxos sub-types were produced and of those the following were mentioned:- Naxos Z. = (Zielanflug = Target Approach): was the original homing device operating on the 8 to 12 cm. band; it could not differentiate between frequencies in the band so that if there was more than one H2S aircraft in the neighbourhood, a confused picture was obtained. Naxos ZR. (R Rückwärts = Backward): employed aerials placed both above and below the after part of the fuselage of the Ju.88 and served as a backward warning device for the approach of British night fighters using Mark VIII or Mark XI on the 9 cm. wavelength. Naxos ZX. (X = X-band = 3 cm. band): was the 3 cm. equivalent of the original Naxos Z. It operated on the 2.5 cm. - 4 cm. band. Naxos RX. was the 3 cm. equivalent of the Naxos R and was used as a backward warner against 3 cm. A.I. Naxos ZD. was a combined homer for both the 9 cm. and the 3 cm. bands. The 3 cm. aerial rotated on the same axis but above the 9 cm. aerials. 25. As stated, the value of Naxos was first appreciated by crews in the early summer of 1944 when the increase in British jamming had reached such a pitch that communications with the ground were affected and it was difficult to find the bomber stream. The picture obtained by Naxos, however, was nonselective and it was not always possible to home on to a single aircraft unless the aircraft in question was separated from the others in the stream. On the other hand Naxos made it easy to locate the bomber stream, which at that period was the main preoccupation of the G.A.F. 26. Although estimate of range could be gained if the height at which the bombers were flying was known, since, by climbing and determining at what point the Rotterdam signals were no longer picked up, the night fighter aircraft could judge the distance of the transmitting aircraft. A full description of the method of approach employed appeared in A.D.I.(K) 125/1945. paras. 93-98. KORFU Z. 27. The original Korfu set, otherwise known as the FuGe.351, was a development of a superhet receiver designed for frequency modulated 9 cm. carrier communications purposes. After the discovery of H2S it was adapted for use by the German "Y" service and towards the end of the war was further modified for use as an airborne set and then became known as the Korfu Z or FuGe.351Z. 28. The aerials employed were of the Naxos type and gave the relative bearing of the transmitter but the advantage of the Korfu Z lay in the fact that it could be sharply tuned and could, therefore, home on to individual aircraft. 29. It was also hoped that with the help of the Korfu Z night fighters would be able to differentiate between H2S and 9 cm. A.I. which the Germans presumed used different sections of the 9.0 to 9.3 cm. band. In this connection, as mentioned in A.D.I.(K) 363/1945, it was hoped in due course to produce the Berlin and other German "9 cm. " radar on the 8.6 to 8.9 cm. band in order to aid German night fighters to differentiate between British and German aircraft. 30. The Korfu Z was to have been ready by mid-summer of 1944 but its advent was delayed by the shortage of magnetrons, all available specimens of which were required for the ground Korfu used by the "Y" service. So far as was known the Korfu Z was never used operationally. Kiel Z. 31. The Kiel Z was manufactured by Zeiss and known officially as the FuGe 280. Infra-red radiations from the exhaust stubs of aircraft were picked up in a parabolic mirror and focused on to an Elac lead sulphide cell. The field of view in a cone of ± 10° was scanned. A wider field of view could be obtained by moving the entire scanner by hand in the same manner as employed with the Berlin M.1.A. 32. Shortly before the end of the war a number of Kiel Z sets were tried out in operations but it was found that, although they gave a range of about 4 km. on a four-engined bomber, various difficulties arose. Infra-red radiations from the moon and stars formed "permanent echoes" on the cathode ray tube used as viewing screen, and were not always easily distinguished from a moving aircraft. In addition, if the target aircraft was between the fires caused by the raid and the night fighter aircraft, the target was obviously quite indistinguishable against the background of the fires. 33. Night fighters equipped with the Kiel Z were also to carry the FuGe 218 Neptun R3 backward warning radar so that they at least had warning of British night fighters approaching from the rear. FALTER 34. Falter was an infra-red telescope of the Bildwandler type used by German night fighters for homing on to British infrared recognition lamps. Reference to Falter appeared in A.D.I.(K) 365/1945, paras. 72-76. It was not known if it had been used operationally. A.D.I.(K)and S.D. Felkin U.S. Air Interrogation. Group Captain 2nd August 1945" |
NJ interception procedures
"SECRET A. D. I. (K) Report No. 599/1944
THE FOLLOWING INFORMATION HAS BEEN OBTAINED FROM P/W AS THE STATEMENTS HAVE NOT AS YET BEEN VERIFIED, NO MENTION OF THEM SHOULD BE MADE IN INTELLIGENCE SUMMARIES OF COMMANDS OR LOWER FORMATIONS, NOR SHOULD THEY BE ACCEPTED UNTIL COMMENTED ON AIR MINISTRY INTELLIGENCE SUMMARIES OR SPECIAL COMMUNICATIONS. G.A.F NIGHT FIGHTERS. R.A.F. BOMBER COMMAND COUNTERMEASURES AND THEIR INFLUENCE ON GERMAN NIGHT FIGHTER TACTICS. 1. The information contained in this report was obtained from a pilot and W/T operator of 7/N.J.G.4 and a W/T operator of 5/N.J.G.1 who were captured after a night operation over Western Germany on October 6th. 2. These are the first prisoners from operational night fighter units to have been interrogated since the German night fighter force retired behind its own frontiers, and although none of them had more than seven operations to call upon for their experience, they were able to provide a fairly complete picture of tactics now being employed. 3. If these two units can be taken as representative, it is evident that the German night fighter force, rather than calling the tune in the interception of R.A.F. night attacks, is now being forced more and more to improvisation. Its tactics are being governed to an increasing extent by the effective countermeasures against its Radar and signals system, and the Germans are quickly reaching a point where they must choose either a radical change in their methods of interception or continued improvisation on the present lines. 4. The present report outlines the tactics now being employed by II/N.J.G.1 and III/N.J.G.4 and shows how, with their signals systems and interception equipment seriously upset by R.A.F. countermeasures, those units are groping for a solution to their ever increasing problems of intercepting the bomber force. TACTICS OF INTERCEPTION. Methods Employed. 5. Whilst II/N.J.G.1 is flying free-lance patrol (Ungeführte Zahme Sau) from the Cologne area III/N.J.G.4, unlike other night fighter units recently examined favours Geführte Zahme Sau. This method depends on D.R. navigation by the aircrews, and on simultaneous tracking by the ground control at Gruppe headquarters, with the addition of a measure of signals control from the same source. 6. Some of the aircraft of 7/N.J.G.4 are also flying by the old type of Himmelbett (G.C.I.) control, the system of the night fighter box controlled by a plotting table, using data from two Würzburgs. On each night the number of aircraft which may fly by that method - usually two or three - is announced, and any of the less experienced crews, within the limits of the permitted number, may do so if they wish. 7. Other forms of control, such as Egon or "Y", are not practised in the two units under review. Early Warning and Readiness. 8. Since the night fighters have retired to Germany at least those units based on the western borders have been robbed of the greater part of their early warning system, with the result that the aircraft, at least of the two Gruppen examined, cannot be put into the air at such an early stage of an impending attack as was previously the case. 9. Recently, therefore, crews have been kept at immediate readiness night after night from dusk until dawn, whatever the weather. Even when the nightly met. briefing indicates that flying conditions make night fighter activity impossible, that state of readiness must continue. 10. In cases where an attack was known to be underway but the probable course of the bombers had not been established, the night fighters have in the past been put up and ordered to orbit a given point near the base airfield, the aircraft being stepped up to 3,000 metres at intervals of 100 metres whilst orbiting. When the point of interception had been decided upon, the aircraft were given an initial bearing by the Gruppe commentary. 11. Since the retreat to Germany, there has been little or no orbiting of the airfield or of beacons by the aircraft of these two units. These P/W were insistent that no standing patrols are now flown, and that the night fighters do not take off until warning of an impending attack is received; occasionally, however, crews are kept in their aircraft at immediate readiness until the situation has been clarified. 12. Upon receiving the first warning from Divisional Headquarters, the aircraft have recently been directed immediately on to a bearing to meet the bomber force. In III/N.J.G.4 at Mainz/Finthen, the whole of the Gruppe - an average effort of 25 aircraft - is usually airborne within 20 to 24 minutes, the first aircraft taking off within about 8 minutes of the first corning. Weather Conditions. 13. The daily briefing of aircraft consists mainly of a summary of weather conditions for the ensuing night, and when the "Weather Frog" reports the prevalence of clouds, the main topic is the possibility of the degree of icing conditions, the worst enemy of the night fighter. 14. In the opinion of P/W, the Germans have never found a satisfactory de-icing system for the night fighters; the Me.110 is without de-icing equipment, whilst the Ju.88 is fitted with the "Kärcher Ofen" - a petrol-burning heater unit - which, however, is not efficient at high altitudes. 15. If a cloud layer is deep and dense, but without icing conditions, the night fighters will operate even if the cloud base at their own airfield is as low as 100 metres; after operations a landing can if necessary be made at another airfield where conditions are more favourable. 16. In considering the expedience of operating in icing conditions, the depth of the ice layer will be taken into consideration; it is possible that the night fighters may risk climbing steeply through an icing area, if it is not too thick, to operate at higher and clearer altitudes. If the bombers are penetrating below a cloud and ice layer, the night fighters will most certainly be sent up to intercept. 17. In this connection P/W were told of a recent Bomber Command attack on Essen, when cloud was at 10/10ths between 3,000 and 7,000 metres and when no German night fighters were put up. Each of these P/W immediately gave his opinion that the non-appearance of the night fighters was certainly due solely to icing conditions. Navigation. 18. During recent weeks when the period of early warning has been considerably reduced, all crews of a Gruppe are given the same initial course before taking off; thus, once all aircraft of the Gruppe are airborne, they are strung out on one and the same track in a form of line ahead. 19. The crews fly by D.R., and the loose formation is simultaneously tracked on a map at Gruppe headquarters. If, in the light of the movements of the bomber force a change of course is necessary, a new bearing will be given to all aircraft simultaneously through the Gruppe commentary. 20. All crews are given strict orders to navigate by D.R., and to accept the Gruppe orders if these differ from their own calculations, so that the tracker at Gruppe headquarters can be reasonably certain that the night fighters are in fact where he believes them to be. The older crews, in spite of this order, are given to "cutting off corners" in the hope of making a quick interception; in such cases the Gruppe commentaries is obviously useless, and such crews must thereafter depend on the Divisional or Reich commentaries and fly free-lance patrol. 21. These crews who stick to their orders are finding D.R. navigation extremely difficult, since this duty falls on the W/T operator, who has his signals and Radar duties to attend at the same time. It is therefore unlikely that the initial formation will be maintained much longer than the completion of the first leg. 22. If this tactic works according to plan the string of night fighters should be brought up to the bomber stream on a parallel or nearly parallel track. At the correct moment, and in accordance with D.R. tracking at headquarters, the night fighters will be given a new bearing which turns the whole line on to the bomber stream in a broadside. By this method at least some of the night fighters must contact the bomber stream with the aid of their S.N.2 equipment. 23. According to P/W, navigation by the night fighters is at present of a low standard, particularly in cloudy weather when ground visual aids are not available. It is evident, however, that the Germans intend to continue operations on these lines, for in III/N.J.G.4. which is equipped with the Ju.88, the crew is to be augmented by a Navigator/W/T Operator, whilst the present W/T Operator will be solely responsible for the Radar equipment. 24. A few weeks ago several experienced observers from bomber units arrived at Finthen, and these men are at present being instructed in night fighting navigation. With the crew of four, the Radar operator will be placed next to the pilot and the Navigator/W/T Operator will sit to back to the pilot whist the B/M will sit - or squat - in the remaining space. Contacting the Bomber Stream. 25. It is perhaps worth noting that the pilot of III/N.J.G.4., who had made seven operations, had never succeeded in contacting the bomber stream, and the Gruppe itself had only claimed one victory since August 8th; that victory was when we attacked Darmstadt or Frankfurt in mid- September. 26. All P/W agreed that the only way to contact the bomber stream is to obey the Gruppe commentary until such indications as target markers, German night fighter flares, Flak and searchlight concentrations or aircraft going down in flames are seen. Unless the flares are spoof, the bombers will sooner or later be contacted by these means. 27. According to P/W, crews are wary of flares, as they have learnt that these may spoof target markers put down to draw unsuspecting night fighters into a Mosquito trap. 28. Providing that the S.N.2 is not too badly jammed by Window, the final contact by the night fighter is made by variations of height of about 1,000 or even 2,000 metres whilst making use of the search gear; this tactic usually commences at as much as 50 km. from the bomber formation, in the hope that a straggler may be picked up. Another reason for this change of height is that in recent raids the heights given by the commentary have been extremely inaccurate, and the height has frequently been corrected on suggestions from such night fighter crews as have made contact with the bombers. 29. The aim in theory is to intercept the bomber stream at its head; this is the only part of the stream of which the precise position is given in the commentary and crews do not, therefore, attempt any finesse regarding the point of entry into the stream. In the words of the present pilot: "We are damned glad to get into the stream, no matter how we do it". 30. Lectures are, of course, given to crews on how to avoid Window and tail warning devices, but P/W pointed out that under present conditions the theory of the lecture room is extremely difficult to put into practise, and a hit or miss method of entry is all that can be hoped for. Attack. 31. The range at which the night fighter opens fire with its forward armament is determined by the pilot himself; whilst some will close in as near as 50/60 metres, the more cautious will open up at a range of 200/250 metres. P/W considered, however, that the normal range might be taken as l00/150 metres. 32. Recognition of the target aircraft is usually by the silhouette in light conditions or moonlight, and by the four exhaust flames in darkness. 33. The present P/W repeated the statement made by previous P/W, namely that the only effective evasive tactic for a bomber about to be attacked is a steep diving turn to port or starboard - preferably the latter - which is on the night fighter pilot's blind side. 34. These P/W could add nothing to previous cements on the Schräge Musik upward firing armament, but they stated that once this armament could be brought to bear it was extremely effective; one officer had claimed a kill with two rounds from the 20 mm. cannon. 35. They stated that the Ju.88 G-1 carried one drum of 50/60 rounds for each cannon; in that type of aircraft the drums cannot be charged in the air, but this quantity of ammunition is ample for one sortie. 36. In this connection, P/W had heard that some night fighters are now being armed with two 30 mm. upward firing cannon in place of the 20 mm.; with this new armament the barrels protrude 12" to 16" above the fuselage and at an angle of 85°. Flak. 37. With two exceptions - orbiting areas and airfields where aircraft are taking off and landing - there are no restrictions imposed upon the Flak in any part of Germany. Night fighters which chase a contact through a Flak area, therefore, do so at some risk to themselves. 38. Old and experienced crews who flew in the days when the use of the FuGe 25a or Verey signals enabled them to quieten the Flak are unhappy about present day conditions, but P/W claim that younger crews who have never known any but these conditions are not particularly perturbed. P/W added that of course a night fighter would only enter a Flak area if it already had an S.N.2 contact; no night fighter would venture unnecessarily in such areas. 39. In orbiting areas, the night fighters will be given a ceiling of, say, 3,000 metres; any unidentified aircraft above that height will be fired on in spite of the night fighters below. The Flak units are usually informed of orbiting areas in advance by the Flak Liaison Officer attached to the night fighter unit. 40. Flak areas in the neighbourhood of airfields occupied by night fighters are forbidden to the aircraft when taking off or landing. I.F.F. 41. For a considerable time there has been a popular belief amongst night fighter crews that the R.A.F. is homing on to FuGe 25a transmissions, and crews of II/N.J.G.1 and III/N.J.G.4, including the present P/W, were no exception. 42. It is difficult to understand how the belief has arisen, since crews were officially told that the R.A.F. has no equipment with which to home on to the FuGe 25a, and orders are that the apparatus must be kept on at all times during flight. 43. In spite of these orders many crews are still switching off their FuGe 25a during sorties, and when on one occasion one of the present crews was shot down by Flak, they had the instrument turned off at the time. At the subsequent enquiry one of the first questions asked concerned the FuGe 25a, but the crew, fearing punishment, maintained that it had been switched on all the time. 44. In addition to the fear that R.A.F. aircraft can home on to FuGe 25a, night fighter crews, including these P/W, have serious doubts as to its efficiency as an I.F.F. instrument. 45. On one of their earlier operations one of these crews was shot at by Flak in spite of the FuGe 25a being turned on, and almost immediately after the W/T operator witched it off the Flak stopped firing. Other crews in both units have repeatedly been fired on both with the FuGe 25a on and off, with the result that the majority has come to the conclusion that as far as the Flak is concerned it does not matter whether the FuGe 25a is used or not and that it is therefore better to leave it off and enjoy the added advantage of not being homed at by R.A.F. aircraft. SIGNALS TRAFFIC. Gruppe Commentary. 46. The Gruppe commentary of both units reviewed was put out on the 3000/6000 Kc/s. frequency band and was received by the aircraft on the FuGe 10-P. In III/N.J.G.4 there were usually one main and two alternative frequencies; until quite recently it was usually found that the main frequency was not jammed. 47. The W/T operator of I/N.J.G.1 stated that on such occasions as the Gruppe R/T commentary was jammed he could call his control with the codeword "Schwingen sie Hammer", whereupon the commentary continued in Morse on the same frequency; in this way W/T operators could often hear the Morse Commentary through the jamming. 48. The Gruppe commentary was put out by II/N.J.G.1 from a mobile van equipped with FuGe 10 and FuGe 16 with the addition, P/W thought, of an amplifier. The FuGe 16 was however, more often than not u/s, and the airfield transmitter was used when starting and homing. 49. In III/N.J.G.4 there was also a mobile van, but in P/W’s experience this was never used and the airfield transmitter was the source of the commentary put out by that Gruppe. 50. Up to the beginning of October 1944 the two units under review, although suffering considerable inconvenience from British jamming of their channels of R/T and W/T control, were able to circumvent the jamming fairly successfully by the employment of large numbers of alternative frequencies and differing sources of control. 51. On the night of October 2nd and 3rd, however, the R/T operator of II/N.J.G.1 found that the whole of the medium frequency band of the FuGe 10 was jammed, as was the whole of the V.H.F. frequency band. After some ten minutes of trying to pick up the Gruppe, Divisional and other commentaries, he switched over to the M/F band and picked up the commentary on one of the Reichluftflotte beacons. 52. Upon returning from this sortie, this W/T operator found that the eleven other crews of the Gruppe who had operated on that night had experienced the same difficulty, and the Gruppe Signals officer thereupon demanded a written report from each W/T operator. 53. The jamming noise on both the 5000/6000 Kc/s. and the 38.4/42.5 Mc/s. bands was described by P/W as sounding rather like a kettle boiling, with the lid rattling in a high pitched tone. 54. Instructions in Morse on the 5000/6000 Kc/s. band can be heard through the jamming when the aircraft is over or near its ground control, and for this reason III/N.J.G.4, which has only operated recently within an area of 150 km. of its base at Mainz/Finthen, has not been troubled to such an extent as II/N.J.G.1, which has been operating much further afield from its control at Köln/Ostheim. 55. W/T operators of that Gruppe have found the FuGe 16 useless, because within two or three minutes of the first words being spoken in an operation, the whole frequency band is jammed; in many aircraft, therefore, the FuGe 16 as no longer carried as being useless extra weight. 56. The whole M/F band was also jammed with a high pitched whistle, but these P/W claimed that they could still hear the Reichluftflotte beacons. They stated that the latter beacon commentaries were now the only real source of control left to the night fighters, and that once these had been effectively jammed, the whole signals system would completely break down. Beacon Commentaries. 57. The Reichluftflotte W/T beacons in Central and West Germany – those with names - only operate, according to P/W, during British night attacks. These beacons transmit the Reich commentary in Morse in the following sequence:- (1) Dash - for D/F’ing (2) Beacon characteristic. (3) Letter C - called the Trennung, separating signal. (4) Commentary: (a) A single figure denoting height of head 58. Early in October, W/T operators were told that one of these beacons in each Jagd Division was to transmit instructions to the aircraft under its control in a special code, in addition to the normal Reich commentary. Thus, for example, if a bomber stream were flying towards Hannover and part of the force detached itself on a southerly course, Jagd Division 3 would call in the night fighters under its control through the medium of this beacon to deal with the new situation. 59. In case of all R/T and W/T channels being jammed or otherwise disturbed, homing instructions to the aircraft were also transmitted through this medium. 60. The code for these beacons was changed at the same time as the Funk Befehl (Tactical W/T Code), which on an average was about once a week. This beacon code consisted of single letters some of which with their meanings one of the present P/W was able to remember:- C = Zurückkehren (Return). B = Fliegen Sie nach 649 (Fly to 649) 649 The code number is that of an airfield. MOS = Mosquito attack; when aircraft of 631 Ju.88 and ME.110 units hear this, they return to base, or they may be ordered to land at the nearest airfield. AGZ = Angriffsziel 631 (Target 631). The number in this case is that of Darmstadt airfield, meaning that Darmstadt is the target of the bombers. 61. Another single letter, which P/W could not remember, signified "Tune in to frequency of Jagd Division 1". Upon receiving this instruction, the W/T operators would first try the short wave frequency of J.D.1 and, if unable to receive the latter, would go over to the frequency of the high powered beacon of that Division. 62. This contingency would occur when there was no bomber penetration in the territory of Jagd Division 3, and when an attack was taking place over the territory of J.D.1. The W/T operators of units of the 3rd Division would remain tuned in to the last Division beacon until ordered to revert to their own divisional beacon. 63. In Mosquito attacks when these are recognised as such, no commentary is broadcast by the beacons. 64. The beacon used for the 3rd Division's code instructions was Kurfürst, and up to October 6th this beacon had not been disturbed, neither had its position been moved; P/W had been told, however, that it was shortly to be moved further East. 65. The beacon Ida has, according to P/W, been moved from its former position to a point S.S.E. of the visual beacon Ida, and now stands approximately at pinpoint 50° 30’ N., 7° 45’ E.; the beacon Kuli since being overrun by Allied advance, has not been replaced. 66. Spoof R/T instructions have a limited success amongst the less experienced W/T operators, but those operators soon learn by experience to recognise a strange voice almost immediately; since the complete jamming of R/T from early October, however, this question hardly arises, at least in Western Germany. COUNTERMEASURES AGAINST S.N.2. Window. 67. The present P/W confirmed the effectiveness of Window countermeasures against the S.N.2 search equipment. Operators are now being told that Window is completely effective if the night fighter is at a range of more than 2,000 metres from a target aircraft; at ranges of less than 2,000 metres a skilled operator can distinguish between the Window blips and that of the bomber. 68. The theory is that the night fighter closes in on the Window at a higher speed than on the bomber, and that the Window blips would therefore travel quickly down the S.N.2 display, whilst the aircraft blip would remain more or less stationery. These P/W, however, were of the opinion that an operator would have to be gifted with a high degree of skill to be able to follow these suggestions, unless, of course, the Window cloud was not too dense. 69. They stated that if Window were only thrown by the bombers, it would be comparatively easy to home on to the Window cloud and thus find the bomber stream, but since the high-flying Mosquitoes had also taken to throwing Window the night fighters could no longer depend on finding the bombers by that method. 70. Thus, in the present circumstances in which Window clouds are widely spread and do not necessarily indicate the presence of the bomber stream, it is extremely difficult, if not impossible, to home on to the bomber stream with S.N.2. alone when Window is present; night fighter crews are, therefore, depending more and more upon the visual indications described earlier in this report. 71. One P/W stated that with the S.N.2 jammed by Window, it frequently happened that a crew would only know that they were in the bomber stream from the air disturbance caused by the slipstreams of the bombers. 72. The question has been asked whether it is likely that as a result of jamming of the S.N.2, the Lichtenstein will be re-introduced to the night fighter units. This has not so far occurred in II/N.J.G.1 and III/N.J.G.4 and these P/W thought it highly unlikely, since the Lichtenstein had in the past been just as thoroughly jammed as is the S.N.2 now. Electrical Jamming. 73. The Germans are firmly convinced that the R.A.F. is jamming the S.N.2 electrically. One of the present P/W had himself experienced what he thought to be such jamming, and had reported this on his return; he was told that it was caused by a "Rauschsender" (Noise Jammer). 74. The other W/T operator had also been told the same story early this year, but he then understood that the effect of the jamming on the display was inconsiderable. In August, this P/W was told officially that it was possible to home, albeit inaccurately, on to the jammer aircraft by switching off the S.N.2 transmitter circuit and using the receiver only. 75. The jamming produced "grass" on both sides of the trace of both the range and bearing tubes, and he was told that the "grass" extended above or below and to left or right of the trace, according to the range and bearing of the jamming aircraft. 76. On the night of October 7th, this P/W experienced a similar display on the S.N.2, and made an attempt to home on to what he thought to be the jamming aircraft, but without any result. MUTUAL INTERFERENCE OF S.N.2's. 77. The S.N.2 of one night fighter will interfere with reception in another if the two aircrafts are within S.N.2 range of one another. The disturbance takes the form in the S.N.2 display of continuous wiggling lines on both height and range tubes; for this reason an eliminator circuit has been installed, controlled by a knob in the bottom left-hand corner of the S.N.2. panel, and W/T operators have instructions to make use of this knob if interference occurs. 78. According to these P/W, it is generally accepted that the eliminator makes not the slightest difference; neither of these two W/T operators had themselves used it. 79. It was stated that, providing there are not more than two other aircraft using the S.N.2 within S.N.2 range of a given night fighter, the aircraft blip can be read through the disturbance an the display, but within a range of 2,000 metres, even the interference produced on the display by one other S.N.2 night fighter is such that the aircraft blip is extremely difficult to see. 80. As on example of mutual interference, the W/T operator of II/N.J.G.1 had heard that about two months ago 40 to 50 night fighters equipped with S.N.2 were sent to intercept some bombers over the Ruhr. The S.N.2's of the night fighters interfered with one another to such an extent that not a single contact was made. P/W himself had not taken part in this operation, but was told about it on the following day. NAXOS. A Lecture on Naxos. 81. Early in 1944, one the present P/W attended a lecture given to I/N.J.G.4 at Florennes by an officer from Werneuchen. The lecture was accompanied by a film, which showed the development of the Naxos display as the aircraft closed in on its H2S target. 82. The lecturer claimed to have made the film himself under operational conditions, and furthermore claimed to have shot down two H2S aircraft with the sole aid of Naxos; it was emphasised that, although the aircraft carried S.N.2 in addition to Naxos, the former was switched off throughout the flight. 83. The film showed the Naxos display initially with two spots of light when the first contact was made at a range of 70 km. As the Naxos aircraft closed in, the spots multiplied and spread round the circular traces of the tube; the circle was completed when the aircraft was directly below the H2S aircraft and at a range of 50 metres. 84. The lecturer was most enthusiastic as to the possibilities of the Naxos and foretold that it would displace all other night fighter aids in attacking H2S aircraft. 85. The type of Naxos shown in the film was the "Z", and the lecturer mentioned two newer and improved types known as the "Naxos-Post" and another which P/W had forgotten. Equipment in I/N.J.G.4. 86. In April 1944, two of the present P/W were at Werneuchen, where for about a month they carried out flight tests on Ju.88's equipped variously with Naxos, S.N.2 and Flensburg. Of 20/24 aircraft which P/W tested in that time, about 16 or 18, equipped with both Naxos and S.N.2, were delivered to I/N.J.G.4; the aircraft which had no Naxos had both S.N.2 and Flensburg. Equipment in II/N.J.G.1 and III/N.J.G.4. 87. It has already been reported that II/N.J.G.1 is equipped throughout with the Me.110, with the exception of one Ju.88 G-1 in the Gruppenstab; this latter aircraft was equipped with the Naxos, but had been u/s since early September. 38. Crews were told that the Me.110 was slow enough without having its speed further reduced by the Naxos, but they were nevertheless led to believe that their Gruppe was soon to be equipped with the Ju.88 in order that Naxos might be employed. Up to the 6th October there was no sign of the Ju.88's. 89. In III/N.J.G.4 some of the Ju.88's had begun to be sent some weeks ago to, P/W thought, Werneuchen to have Naxos installed. On October 4th or 5th, at least one of these aircraft had been returned to Finthen equipped with Naxos. Leader Aircraft. 90. When, up to mid-August, II/N.J.G.1 was based at Deelen, the Naxosequipped aircraft flown by the Gruppenkommandeur was employed as a shadowing aircraft to home on to H2S transmissions of incoming bombers and to report their position and composition to the Gruppe. 91. This shadowing aircraft was known as the Führer (Leader), or sometimes the Aufklärer, (Reconnaissance), and at the first indications of an R.A.F. attack it took of early - before the remainder of the Gruppe - and made contact with and flew with the bomber stream. 93. The Division in turn passed such information as was necessary to the night fighter Gruppen under its control, and this information was received by the latter on the Tannoy system. 94. When the night fighters took off to intercept the bombers, the information from the leader aircraft was put out in the form of a Gruppe commentary; the night fighters could not communicate with the leader aircraft. P/W did not know if the ordinary commentary was ignored and all dispositions were made solely on the basis of the shadowing aircraft's reports, or if other sources of information were used simultaneously as a basis for the Gruppe commentary; he rather inclined to the former. 95. Reports by the leader aircraft continued during a raid and included details such as flares laid, Flak being encountered, and any aircraft shot down in flames. 96. Once the interception force had been led to the bomber stream with The help of the leader aircraft, the latter dropped flares of varying combinations of colours to mark any turning points of the bomber stream, at the same time informing the Divisional headquarters. The night fighters were simultaneously ordered by their ground control to fly on to the flares, or to fly on a specific bearing from these flares. 97. The pilot from III/N.J.G.4 believed that in some units the jammer aircraft communicate direct with the night fighters under their control, and issue vectoring orders to them. In all cases however, once the night fighters have been brought up to the bomber stream, the leader aircraft is informed by the Division, and thereafter it assumes the function of an ordinary night fighter. Night Fighter Flares. 98. These P/W had heard that the Führer aircraft procedure was falling into disrepute, because on occasions considerable time had been lost between take-off of the leader aircraft and that of the reminder of the night fighters, so that in consequence the night fighters had frequently failed to contact the bombers. 99. This story is perhaps strengthened by thy fact that more recently, at least in III/N.J.G.4, al1 Ju.88’s have been carrying three or four flares on each sortie. When a night fighter makes contact with the bombers, three flares are dropped in or near the bomber stream as a signal for other night fighters that the bombers have been contacted; the flares indicate the position of the stream. 100. Until early in October these flares were always composite whitered- white, each colour burning for one minute in a varying sequence which was changed from night to night. Just recently, however, crews have been told that new colour combinations of red, white, yellow and green would shortly be coming into use. Single-engined Fighters with Naxos. 101. Whilst at Werneuchen one of these P/W saw Me 109’s and F.W. 190’s – which they heard were destined for a "Wilde Sau" unit - equipped with Naxos. In the F.W. 190 the Naxos dome was fixed to the after part of the sliding part of the cockpit cover. P/W could give no further information and had not noticed how the aerial array was mounted, but he was certain that the dome moved back with the cockpit cover. FLENSBURG. 102. Neither II/N.J.G.1 nor III/N.J.G.4 have any aircraft equipped with Flensburg, but during the first week of October two new Ju.88 with both Flensburg and S.N.2 were delivered to the 7th Staffel. P/W did not know the reason for this delivery, and he had understood that the Flensburg had fallen out of use. REACTIONS TO MOSQUITO INCURSIONS. 103. The R.A.F. Mosquito incursions are giving the Germans cause for some serious thought and, according to P/W, much inconvenience and disturbance is being caused both by the intruders and the small attacking forces. 104. Intruders over airfields are, of course, a considerable cause of disturbance, and it is very seldom that a night fighter crew can land on its base in peace. Added to this, there is always a sense of uneasiness amongst crews during sorties, with the result that their efficiency is much impaired. 105. One of the present P/W - the pilot - went so far as to say that he would shoot at any twin-engine aircraft without waiting for a recognition of type, which is strictly against the present rules. 106. The same P/W was of the opinion that at present it is often impossible for the ground warning system to establish whether a penetrating force is composed of Mosquitoes or heavy bombers, and that as a result the night fighters must be put up, if only as a precaution, until such a time as the true composition and intentions of the force are established. 107. When a penetration force has been identified as a Mosquito formation, the Me.110 and Ju.88 night fighters are not put in the air, and the Reichluftflotte W/T beacons do not transmit a commentary. It was suggested by P/W, however, that He.219's were being-put up to intercept Mosquitoes. 108. It has often happened recently that night fighter units have been put in the air to intercept large four-engined bomber formations which have only later been identified as smaller Mosquito formations. This has resulted in much waste of effort, to say nothing of petrol, since the night fighters were recalled as soon as the attacking force was identified. 109. In a recent lecture to III/N.J.G.4, crews were told that a small formation of Mosquitoes could with the help of a special apparatus and a low speed, lead the Germans to believe that a large formation of fourengined bombers was underway; crews were given no details of this special apparatus. 110. It is interesting that of the seven operations which the W/T operator of II/N.J.G.1 had made, no fewer than three were false calls caused by Mosquitoes. In these sorties the crews had been sent up to intercept four-engined aircraft, and after having been airborne for 1 to 11/2 hours they had been called back to base and told that the supposed heavy bomber force was only a Mosquito formation. The W/T operator of I/N.J.G.4 had made six operations, and of those two were similarly false calls for Mosquitoes, on which the night fighters had been recalled after having been airborne for 3/4 - 1 hour. 111. On one occasion early in October, on the other hand, the aircraft of II/N.J.G.1, at that time based at Düsseldorf, had been stood down after an early warning of a "Mosquito penetration". Soon afterwards, however, cascades of flares were seen falling near the airfield and it was thought that the airfield itself was about to be attacked. 112. The attack was, in fact, on München/Gladbach, and Oberleutnant LAU thereupon took off alone at about 2300 hours. That officer shot down two four-engined bombers and landed again after having been airborne for 22 minutes. 113. The two W/T operators amongst these P/W were sufficiently cooperative to compile diaries of the sorties which they had made; although naturally they could not remember dates with any degree of reliability, their notes include an indication of the inconvenience and waste of ill-spared fuel of which the Mosquito incursions are the cause. 5/N.J.G.1. 114. (1) On 27th august, 1944. Took off from Deelen at about 2230 hours. This crew was ordered to fly direct to the W/T beacon Quelle, because, it was said, a bomber force approaching the Weser estuary from the North Sea was likely to fly to the Hanover/Brunswick area. This aircraft, about the fifth to take off from Deelen, flew for a time on D.R. whilst the W/T operator listened to the Gruppe commentary. He then switched over to the W/T beacon and used that commentary. The pilot made a left-hand turn and at the same time heard on the beacon commentary that the bombers were heading for Hannover. By this time, however, petrol was running low and the crew decided to break off; they landed in Oldenburg. The S.N.2 was u/s from time of take—off. This crew only learned afterwards that they had been directed by the Gruppe commentary to fly to Mannheim, where an attack was taking place, but since by the time the Mannheim attack had been identified they had switched over to the beacon commentary, they had not heard this order to the Gruppe. During the afternoon of the day following these raids, an operations officer of Jagd Division 3, Hauptmann KNICKMEIER, came to Deelen and gave all the crews a talk on the raid of the previous night. He told them that the night fighter sortie had been a failure because as soon as he knew that Bomber Command were making two penetrations he had ordered all aircraft of II/N.J.G.1 to break off from the more northerly penetration and to make for the other bomber stream going for Mannheim. This, he stated, had 1ed to some confusion and, therefore, in the future the night fighters would be allowed to continue to fly according to their first orders, and no attempt would be made to divert them to intercept any subsequent attack. (2) Early September. Took off from Düsseldorf at 2225 hours. Objective Stettin - Kiel. Commentary gave false direction of penetration as Weimar. No interception. Landed at Jüterbog. (3) Mid-September. Took off from Deelen at 2350 hours. Mosquito attack. Landed at Deelen after 1/2 hours. (4) Mid-September. Took off from Deelen about 2300 hours. Mosquito attack. Landed at Deelen. (5) End September. Took off from Düsseldorf about 2230 hours. Mosquito attack. Ordered to W/T beacon Christa. Landed at Mainz/Finthen. S.N.2 mutual disturbance. (6) October 2nd or 3rd. Took off from Düsseldorf at about 2230 hours. Heavy bomber penetration with München-Gladbach as objective. S.N.2 contacts near Münster. Enemy aircraft bombed through gaps in cloud from 4,200 metres. Commentary gave false height. Saw four 4-engined aircraft, but could not close in because they disappeared into cloud. White, red and green cascade flares. Heavy Flak; several aircraft seen going down. Landed at Gütersloh after 21/2 hours. (7) See A.D.I.(K) 365/1944. 7/N.J.G.4. 115. (1) August 7th or 8th. Airborne landings in Seine Estuary. Took off at about 2300 hours. No contacts; ordered to return after 11/2 hours. (2) August 9th. Ordered to W/T beacon Mücke, shot down by own Flak and bailed out over Nassolt. (3) End August; Took off from Twente. Mosquito attack. (4) Mid-September. Took off from Mainz/Finthen at 2300 hours. Flares at Frankfurt or Darmstadt - apparently Mosquitoes. Ordered to land after 11/2 hours. No contacts. (5) About September 20th. Took off at about 2200 hours. Bombing in Frankfurt area. Saw 4-engined aircraft on opposite track held by searchlights, but did not go after it as it was at a greater height. Window upset S.N.2. (6) October 6th. Took off from Finthen at about 2000 hours in direction of Kaiserslautern. S.N.2 electrically jammed; tried to home on jammer without success. Got lost and shot down by U.S. Flak. Ground Attack. 116. At the closing stages of the French campaign some of the night fighter units, including II/N.J.G.1 and III/N.J.G.4, were given the extra duties of attacking ground targets with their forward armament - duties which proved both expensive in aircraft and unpopular with the crews. 117. Since their return to Germany, neither of these two units had attacked ground targets, but on the night of October 6th an order was re-introduced into II/N.J.G.1 to attack ground targets if any suitable objectives were seen. A.D.I.(K) S.D.Felkin, 2nd November, 1944. Wing Commander." |
Aufklärer and Verbandsführer aircraft
Item 34 onward:
"SECRET A. D. I. (K) Report No. 700/1944 THE FOLLOWING INFORMATION HAS BEEN OBTAINED FROM P/W AS THE STATEMENTS HAVE NOT AS YET BEEN VERIFIED, NO MENTION OF THEM SHOULD BE MADE IN INTELLIGENCE SUMMARIES OF COMMANDS OR LOWER FORMATIONS, NOR SHOULD THEY BE ACCEPTED UNTIL COMMENTED ON AIR MINISTRY INTELLIGENCE SUMMARIES OR SPECIAL COMMUNICATIONS. GERMAN NIGHT FIGHTERS. A REVIEW OF CURRENT GERMAN TACTICS. 1. Three recent A.D.I.(K) Reports, Nos.508, 599 and 620, have described current German night fighter tactics in some detail and have shown how the night fighter force, robbed of much of its early warning and at the same time the victim of extensive radio countermeasures was, up to the beginning of October 1944, forced into improvisation in its tactics. 2. This report has been compiled with the object or examining the extent to which the Germans have varied their tactics during October and November to meet the continued and successful countermeasures employed by R.A.F. Bomber Command. 3. The present information has been obtained from a pilot, a radar operator and a W/T operator of 3/N.J.G.2 shot down in Holland on the night of November 29th, and from a pilot of the same Staffel shot down in Belgium on the following night. 4. These prisoners confirm the fact that the situation at the end of November remained much the same as in early October; the following paragraphs therefore, whilst adding little to present knowledge of German tactics, have their value in showing the situation as it was on the more recent date. Present Use of SN 2. 5. A re-examination of the conditions under which the night fighters are operating their search equipment shows that, at least in the neighbourhood of a bomber stream, interference by jamming is such as to render the SN2 completely useless. Resort to the alternative frequencies - of which there are two - had in P/W's experience made not the slightest difference; he described the disturbance as taking the form of grass on both sides of the traces on the range and bearing tubes. 6. These P/W expressed the opinion that of late Bomber Command has been making less use of window in favour of airborne jammers known as Rausch-Sender (see A.D.I.(K) 599/1944 paras.73 - 76); little interference from Window has in fact been experienced recently by crews of I/N.J.G.2. 7. Like their predecessors, the present P/W were not seriously disturbed by the prospect of Window jamming; recent recommendations had laid down that under certain conditions the aircraft blip could be distinguished through the Window disturbances by the difference in their relative rates of movement down the SN 2 display. 8. In some of the aircraft of I/N.J.G.2 an attempt has been made to reduce the effects of electrical jamming by mounting the SN 2 aerial diagonally instead of vertically; these P/W had, however, no first-hand knowledge as to whether this expedient did or did not improve the situation. 9. An indication of its lack of success may be that during October the Gruppe Signals Officer had told the new aircrews that a new version of SN 2 was in course of development but that meanwhile they would have to make the best of present conditions and take advantage of periods when jamming was not present. 10. The Signals Officer did not divulge the name of the new apparatus, neither did he tell the crews when they could expect it to be introduced into operations; gossip in the Staffel had it that the new apparatus would be the SN 3. 11. The Gruppenkommandeur of I/N.J.G.2, Hauptmann RATH, now publicly claims to have been a life-long adherent of "cat's eye" night fighting and avers that all his victories have been achieved without the use of search equipment. 12. It is perhaps worth repeating that, as far as these prisoners knew, there is no question of re-introducing the Lichtenstein; one P/W, stated that that apparatus has completely fallen out of use and is not even employed in training. SN 2 as Tail Warning. 13. Since the introduction of SN 2 into operations, all prisoners interrogated have stated that that apparatus in its present form is capable of giving a tail warning, although at a comparatively shorter range than its forward capabilities. 14. In I/N.J.G.2 there has recently been a further development in the improving of the tai1 warning; at the beginning of November new deliveries of Ju.88 G-6’s began to arrive with an aerial array for tail warning installed at the extreme end of the aircraft tai1 unit. 15. This array consisted of one dipole carrier similar to those used for the normal SN 2 forward array, but with the dipoles placed in a horizontal position. 16. By the end of November, the Gruppe possessed some ten aircraft equipped in this manner; these P/W had themselves had no experience with this innovation but had understood that a picture only appeared in one tube of the SN 2 display - they thought the azimuth tube. Naxos and H2S. 17. Some time in early October, crews in I/N.J.G.2 began to complain amongst themselves that something had gone wrong with Naxos; whereas until that time it had been considered entirely efficient, and they had always been able to count upon obtaining large numbers of H2S contacts from a raiding force, they had now begun to obtain so few contacts as to arouse the suspicion that the R.A.F. had come to known about Naxos and was playing tricks with it. 18. Up to the end of November, nothing had been said officially by any of the senior officers, but the opinions of radar and W/T operators may be summarised as (a) that H2S is not being used to the same extent as formerly, (b) that the R.A.F. has an H2S of a new type or with a new frequency, and (c) that in some way Naxos is being jammed. 19. Of the 25-30 aircraft it the Gruppe, about half are equipped with Naxos. Flensburg. 20. About ten of the aircraft of I/N.J.G.2 are equipped with Flensburg and according to these prisoners it frequently occurs that Ju.88-G is delivered with this apparatus installed. 21. Crews are at a loss to understand why the Flensburg is still being delivered since the apparatus has fallen out of use. At one time attempts were made to remove the internal part of the equipment to save weight in the aircraft, but a sharp reprimand came from higher quarters and it was duly put back. At all events, official instructions on present intentions with the Flensburg are entirely lacking. 22. It is perhaps worth repeating that the present radar operator P/W had been told by one of the experienced W/T operators of a possible use of the Flensburg as a warning of enemy aircraft. 23. It was said that a Monica signal always appeared within two limits on the Flensburg display; any signal appearing on either side outside those limits was an indication of either a ground radar pulsation, that from an SN 2 or from Allied A.I. 24. There was said to be no method of distinguishing between the three types of signal, but it would be possible to obtain an indication of whether a transmission originated from below, above or at the same level. In this way, it was claimed, Flensburg at least gave an indication that another aircraft, possibly a Mosquito using A.I., was in the vicinity. 25. One of the present crews had Flensburg installed in their aircraft but they had never taken an opportunity to try out the recipe described above. SIGNALS TRAFFIC. German Reaction to Continued Countermeasures. 26. The fact that at the beginning of October the German night fighter force was reduced to only one reliable signals channel - the high powered W/T beacon commentaries - was reported in A.D.I.(K) 599/1944 para.46 et seq. The present interrogations, whilst producing little that is new, have once again confirmed that the situation with night fighter signals was as previously reported and, in fact, remained little changed at the end of November. 27. In I/N.J.G.2 the W/T operators had been experiencing exactly the same difficulties as in the other units recently examined; the present P/W stated that they too had found the Divisional and Gruppe commentaries on the M/F and H/F bands seriously jammed from about the middle of September, and they too had been forced to resort to the Divisional commentary put out by the high-powered W/T beacons. 28. On rare occasions, it has been possible to hear the Gruppe morse commentary (Gruppen Tastführung) through the jamming but results are in the majority of cases so uncertain that operators waste no time and go straight over to the beacon commentaries; the latter present no difficulties. 29. These P/W described the jamming note on the Fu.Ge.10P frequencies as being a rising and falling whistle. The VHF frequency band of 38.4 - 42.5 Mc/s has fallen completely out of use for the purposes of commentaries, but in the FuGe.16 was still used at take-off and for landing at the base of the unit at Kassel. 30. Thus, the present situation is that the night fighter Gruppen can no longer operate as units, but each individual crew must judge the situation for themselves from the information given by the beacon commentary and must themselves decide whether they shall attempt to intercept the bombers or give up the chase; if the search equipment is jammed, and the homing equipment produces no reactions, then the night fighter operation is reduced to the level of a Wilde Sau sortie. 31. One further complication which arises when the Gruppe commentary is inaudible is that crews listening to the Divisional commentary from the high-powered beacons often miss orders given to aircraft of the Gruppe, with the result that recall orders are frequently not heard and much effort is wasted in aircraft flying about aimlessly. 32. Eventually, when the attack is over and jamming has been withdrawn, crews will return to the Gruppe frequency and then belatedly hear the orders to return to base. 33. It is perhaps worth adding that the aircraft of I/N.J.G.2 have not been flying by the Himmelbett (Würzburg-Freya controlled) method. RECONNAISSANCE AND LEADER AIRCRAFT. Definition. 34. The prisoners were able to clarify the question of the so-called formation leader (Verbandsführer) described somewhat inadequately by previous P/W and reported in A.D.I.(K) 599/1944 paras.90-97. 35. It transpires that two separate categories of aircraft with totally differing functions are employed; one, known as the Aufklärer (Reconnaissance) has the duty of taking off before the main formation and of contacting and reporting on the composition and movements of the bomber stream. 36. The other aircraft, the Verbandsführer, is the leader of a night fighter formation and, in an attempt to keep the unit together, that aircraft transmits periodical D/F signals, on to which the others are supposed to home, and which in theory have the effect of keeping the formation together. 37. Neither system has recently been working satisfactorily, largely owing to the jamming of signals channels. Nevertheless, in I/N.J.G.2 nightly preparations were made for putting reconnaissance and leader aircraft up, should Divisional Headquarters decide that it was necessary. 38. The functions of these two aircraft described in turn below. Verbandsführer (Formation Leader). 39. The Verbandsführer aircraft it normally flown by an experienced senior officer such as the Kommandeur or a Staffelkapitän, and his aircraft always takes off with the main force of the Gruppe. 40. When ordered to take off, the aircraft of the Gruppe fly an initial course in the normal manner. Thereafter the duty of the Verbandsführer is to transmit a periodical D/F signal of two minutes duration at 10, 15 or 20 minute intervals, together with a pre-arranged single code-letter; the aircraft of the formation are expected to home on these signals and thus maintain a compact formation. 41. The code letter and the exact times at which the D/F signals shall be transmitted are arranged at nightly briefings. 42. In I/N.J.G.2 the D/F signals were given on the long wave band of the FuGe.10, with the addition of short-wave R/T or W/T instructions by the Verbandsführer to the formation on changes of course and height; only the leader aircraft was permitted to transmit. 43. The leader aircraft supplemented the R/T orders by the firing of prearranged verey signals as a guide to the bomber stream. 44. The Verbandsführer system had one serious disadvantage in that the D/F signals when given at the longer intervals, had the effect rather of scattering the formation after the first leg of a course from base, since the aircraft of the formation were apt to zig-zag across the leader's track at each succeeding D/F signal. 45. Up to the middle of September the Verbandsführer procedure could be said to be operating fairly satisfactorily, but when jamming of the frequency bands of the FuGe.10 commenced, its operation became impossible and in I/N.J.G.2 the procedure was dropped. 46. Divisional orders to operate a Verbandsführer still stand, and a routine daily briefing on procedure and callsigns was still held with I/N.J.G.2; Hauptman RATH, the Kommandeur, openly admits, however, that, under present conditions he has no intention of operating a Verbandsführer and by holding the briefing he is merely obeying Divisional orders in the spirit. Reconnaissance (Aufklärer aircraft). 47. The duty of the Aufklärer aircraft is to make contact with the bomber stream with the help of ground control, Naxos and SN 2, and then to report directly and solely to Divisional headquarters on its composition and movements. The Aufklärer is usually one of a number detailed daily from the ordinary night fighter Units. 48. In I/N.J.G.2 the crews of from one to three aircraft equipped with Naxos were briefed nightly to stand by for Aufklärer duties; orders to take off came from the Division, and once airborne the aircraft operated entirely under Divisional control on a special frequency known as the Aufklärer Welle. 49. Once the Aufklärer had served its purpose of contacting and reporting on the raiding force, that aircraft, on orders from the Division, assumed the duties of a normal night fighter. 50. It usually happened that orders to the Aufklärer to take off preceded those to the main force by anything from ten minutes to one hour; the Aufklärer detailed in I/N.J.G.2 were sometimes ordered up singly, whilst at other times two or three took off together. If no orders came from Division, then the Aufklärer took off with the main force and operated as normal night fighter. 51. Since the beginning of October, the Aufklärer aircraft, although briefed and standing by nightly, had not been ordered up by Division. These P/W were of the opinion that of late the channels of “Y” control had been so seriously disturbed as to make the procedure impossible in Western Germany. Additionally the air situation had recently been so confused that nothing more could be done than to order the main force of night fighters to take off at the last moment - and very often too late to be of any use. TACTICS OF INTERCEPTION. 52. The following paragraphs of necessity take the form of notes and additions to the account given in A.D.I.(K) 599/1944. The methods used in I/N.J.G.2 have been found to follow the same principle as those used by other units; the present P/W were, however, able to clarify several points and to enlarge upon others. Readiness. 53. Standing patrols were not flown by I//N.J.G.2; as with other units examined recently, a met and signals briefing was held each evening and crews remained at readiness in the crew-room during the whole of the night or until such a time as they were called on the Tannoy laid on in the room. 54. The aircraft were lined up at a dispersal and the engines were only started up after a crew or crews had been called to take off. In this case the first aircraft could be away within 8 minutes of the crew being called; it had occasionally happened that crews were detailed to sit in the aircraft, but with the engines still. 55. Should an order to take off prove to be a false alarm and the aircraft be ordered to return, crews resumed their original state of readiness and the fuel tanks of the aircraft which had returned were immediately topped up ready for another start. 56. In the case of double sorties being flown, crews who returned to their base airfield after the first sortie resumed their original state of readiness. Such aircraft as landed on other night fighter bases, however, were temporarily attached to the unit which they visited, and received signals briefing as though they belonged to that unit. Take-off. 57. There is no predetermined point at which the night fighters are put up to meet a raiding force, and sources of early warning of bomber penetration are, of course, unknown to the majority of operational crews. 58. In the experience of these prisoners, the order to take off was occasionally accompanied by a note as to the position and direction of the bomber force, but often, as on the last sortie of the 4R + RL on the night of November 29th, the night fighters were simply ordered to make for a given high powered W/T beacon and to await further orders. 59. In the days before the Gruppe commentary was jammed, the aircraft were went to assemble over or near their base airfield, after which orders were given as to course and height to meet the bombers. Under present conditions, each crew or batch of crews ordered into the air is given an initial course which takes them to a beacon, or which is calculated to bring them directly to the bomber stream. If, after the first leg, no contact is made, the crews must do the best they can from the beacon commentary. Navigation. 60. Navigation in I/N.J.G.2 follows the general practice amongst German night fighters in that an attempt is made to navigate primarily by D.R. with the additional help of ground navigational aids; it was stated that at present the only reliable aids were the visual and radio beacons. 61. One of the present P/W had the idea that some aircraft of the Gruppe, including those of the Kommandeur and Staffelkapitäne, were using Bernhardine as an additional aid, but he could give no further details. He had understood that the method of determining a position was by means of a succession of sine curves along a horizontal base, with a series of figures at the points where the curves struck the base line. Contacting the Bombers. 62. These prisoners repeated that no attempt is or can be made to operate in any specific part of the bomber stream, and under present conditions crews are content to have found the bombers at all, no matter how or where. 63. Once in the stream the night fighter crew will attempt to remain there, and it is only if chased off by a Mosquito or through lack of fuel or other defects to the aircraft, that the pilot wi11 deliberately leave the stream again. 64. The commentaries are broken off as soon as an R.A.F attack has finished - at least as far as the recent shallow penetrations have been concerned – and the question as to whether the returning bomber shall be followed on their homeward track lies entirely with the night fighter crews, and depends largely upon the amount of fuel remaining in the aircraft. 65. There are no restrictions as to how far beyond the German border the night fighters shall fly, but these P/W pointed out that after the bomber attack is over, the night fighter has no commentary to help him. I.F.F. 66. At the beginning of November the Signals Officer at I/N.J.G.2 announced that the R.A.F. had equipment for homing on to FuGe.25a transmissions; he nevertheless told crews that the order to keep the I.F.F. switched on must stand, but he added the order that the apparatus should be turned off when leaving German territory. Armament - German and R.A.F. 67. The rear armament of one M.G.131 in the Ju.88 G-6 is intended solely for defensive purposes. The majority of crews felt that this armament was an unnecessary extra weight, and these P/W themselves had never heard of a case where it had been used in combat. 68. As far as R.A.F. armament is concerned, crews in I/N.J.G.2 at least have no knowledge of the use of radar aids by R.A.F. gunners. These P/W stated, however, that tracer fire from a bomber has distinct deterrent effect upon all but the most hardened night fighter crews. Petrol. 69. There has been no noticeable shortage of petrol in I/N.J.G.2 and according to these P/W there have been no orders to economise. The sole indication of any shortage was a recent restriction in SN 2 practice flights by day. Night Rocket Phenomena. 70. The question has been asked as to whether the Germans are using jet propelled aircraft at night. These prisoners had not heard of the use of this type of aircraft and were inclined to ridicule the suggestion. 71. They themselves had seen rocket traces at night and had attributed these to rocket Flak; they had had to draw their own conclusions, however, since officially they were told nothing. 72. One of the present pilots had twice encountered enormous flaming masses over Berlin some time ago; he had at first thought these to be aircraft going down in flames, but on the second occasion he was close enough to make a careful observation and could see that the rate of fall was too slow for a crashing aircraft. Again, he had been told nothing officially. THE NIGHT FIGHTER'S DIET. 73. The fact that night fighter crews must now depend more and more upon good night vision has prompted an enquiry into the measures being taken by means of diet and drugs to maintain a standard of night vision in I/N.J.G.2. 74. The familiar black pills formerly distributed to night fighter and bomber crews in the G.A.F. were absent in this unit. The normal diet of the night fighter was given by one of the present P/W as follows:- Breakfast: 30 grammes of butter, White bread, One egg, 50 grammes of sausage, ½ litre of fresh milk, Ersatz coffee. Lunch: Soup; varying from meat and vegetable to noodle. Meat and 2 veg., Pudding (occasionally}. Supper: 45 grammes of butter, 80 grammes of sausage, Black bread, Jam or artificial honey, 8 cigarettes 75. When returning from a sortie, the night fighter is given the following special issue:- 25 grammes of chocolate, 25 grammes of coffee beans (real), 2 packets of boiled sweets, 1 cake of dried fruit, Biscuits. A.D.I.(K). and U.S. S.D. FELKIN Air Interrogation. WING commander 30th December 1944" |
Re: Using Ultra to research the Luftwaffe
Quote:
My website is still alive (I just checked) and both those links work for me. Another site with a selection of transcribed ADI(K) reports is: http://www.cdvandt.org/felkin_reports.htm. The emphasis there is on radar and communications systems. |
NJ developments
"SECRET A. D. I. (K) Report No. 125/1945
THE FOLLOWING INFORMATION HAS BEEN OBTAINED FROM P/W AS THE STATEMENTS HAVE NOT AS YET BEEN VERIFIED, NO MENTION OF THEM SHOULD BE MADE IN INTELLIGENCE SUMMARIES OF COMMANDS OR LOWER FORMATIONS, NOR SHOULD THEY BE ACCEPTED UNTIL COMMENTED ON AIR MINISTRY INTELLIGENCE SUMMARIES OR SPECIAL COMMUNICATIONS. G.A.F.NIGHT FIGHTERS. RECENT DEVELOPMENTS IN GERMAN NIGHT FIGHTING. 1. Between the opening of the Rundstedt offensive on 17 December 1944 and the night of 1st January 1945, fifty-nine German night fighter aircrew captured on the Western Front were brought to England for interrogation by A.D.I.(K). Of these prisoners, ten were selected as being suitable for special interrogation with the object of investigating current German tactics, and the extent of their deviation from methods employed up to the end of November and reported in A.D.I.(K) 508, 599, 620 and 700/1944. 2. The present report is based on the interrogation of these ten prisoners, who came from III/N.J.G.1, II and III/N.J.G.2 and II, III and IV/N.J.G.3, and of whom one had recently spent some time at the G.A.F. radar experimental station at Werneuchen. In addition, there was one prisoner who had spent one year as a ground radar mechanic with I/N.J.G.4 and had then transferred to the Schulstaffel of the same unit to train as a radar operator. The Schulstaffel had been dissolved at the end of October 1944 and its personnel posted to the infantry; this P/W fell into Allied hands as an unwilling member of the Waffen SS. 3. From interrogation of previous night fighter prisoners - captured between September and the end of November 1944 - it has been amply proved that the German night fighter force has been at a loss to overcome the successful Bomber Command spoofery and radio countermeasures and as yet has made no progress in its efforts to overcome this disadvantage. 4. From the present interrogations there are signs that the Germans, not content to let the matter rest as it is, are striving to gain the upper hand over Bomber Command by the introduction of at least two new measures. One of these, discussed in the following paragraphs, is the employment of Bernhardine beacons for the dual purpose commentary and navigation, and the other - as yet in its early stages - the probable introduction of a new type of search equipment, the SN 3. Details of the latter are at present lacking, but evidence suggests that it may be of the nature of centimetre A.I. BERNHARDINE – FuGe.120. Earlier Vicissitudes. 5. As far as G.A.F. prisoners are concerned, Bernhardine is no innovation, as early as May 1942 hazy allusions to this form of navigational aid were made by prisoners, but the first mention of Bernhardine by name was made by an officer of 1(F)/121 captured in October 1943 (A.D.I.(K) 498/1943; thereafter nothing further was heard until K.G.66 opened its pathfinder operations over England early in 1944. 6. A prisoner from 5/K.G.66 captured in England on 25th March 1944 gave an account of Bernhardine which, in the light of the present interrogation proves to have been remarkably accurate (A.D.I.(K) 187/1944, paras.19 – 24) 7. In October 1943, 5/K.G.66 had had 1 Do.217-M equipped with Bernhardine, but after some experiments the experts had come to the conclusion that the apparatus was not sufficiently accurate for pathfinder operations; the P/W concerned had heard later that work on the ground installations had ceased. 8. In spite of continued interrogation of subsequent prisoners, nothing more was heard of Bernhardine until late in December 1944. The capture of a prisoner from III/N.J.G.1 on 17th December 1944 and other prisoners from II and III/N.J.G.3 later in the same month has now revealed that Bernhardine is being seriously considered - if not already used - not only as an aid to night fighter navigation but as a source of the commentaries. Introduction of Bernhardine to Night Fighting. 9. Some time in October 1944, crews of 8/N.J.G.1 were given a preliminary lecture on Bernhardine in which its principles were explained, they were told that it was no new discovery but would shortly be introduced to night fighting. In III/N.J.G.3 crews had also been given frequent lectures and by November some of the aircraft of that Gruppe already had the necessary apparatus installed. 10. According to prisoners who attended these lectures, the transmissions from the ground station take the form of a conventional twin lobe polar diagram with an equisignal area and with a very small amount of rearward radiation. A signal transmitted from the ground station once every minute is translated by the airborne apparatus into a teleprint message on a paper tape giving the QTE (true bearing) of the aircraft from the ground transmitter followed by a further image in figures and letters which is a Divisional commentary of the type at present broadcast by the high powered W/T beacons. 11. It was explained that the Bernhardine transmitters would operate on 32 frequencies between 30.0 and 33.1 mc/s, and that the signal would be received through the normal E.Bl.3 in the aircraft. Thus the first 32 of the 34 spot frequencies of the E.Bl.3 would be used for Bernhardine whilst the remaining two, 33.2 and 33.3 mc/s, would be retained for blind landing purposes. 12. It is claimed by P/W that Bernhardine signals are unjammable and that transmissions have a range of 400 - 500 kilometres. 13. A captured night fighter map, recovered from a recent crash in Belgium and issued by the signals officer of N.J.G.3, was marked with Bernhardine transmitters at approximately the following pinpoints;- N° 0(?) Berlin 52°13'N;13°6'E N° 8 Alkmaar, Holland. 52°42'N;4°38'E N° 9(?) Leck 54°41'N;9° 2'E N° 10 Thisted, Denmark. 56°42'N;8°33’E N° 11 Breslau 51°25'N;17°5’E N° 12 Pilsen 49°45'N;13°15’E 14. A further indication that Bernhardine may already be in operational use was found in a file of signals orders from an aircraft of II/N.J.G.1 shot down on December 31st. On the same page as the usual numbering of the Y-line frequencies was another column headed "Kanäle" (= channels); the channels were numbered from 1 to 32 and to each number was appended a frequency, commencing with 30.0 at No.1 and rising by .1 mc. to 33.1 mc/s at No.32. 15. Both of the above documents have been forwarded to A.I.4(b). Airborne Apparatus. 16. The Bernhardine apparatus in the aircraft is contained in a box measuring some 60 cm in width, 30 cm in height and 20 cm in depth, placed in the JU.88 in some cases to the right of the W/T operator on the lower port wall of the fuselage and in others to the left of the W/T operator or in the forward instrument panel. 17. The front of the box has a wide glass-covered slot about 40 cm. in length and 12 cm. in depth along which the paper tape travels from right to left after the necessary data have been printed upon it by a teleprinter contained in the box. The on-off switch for the apparatus, marked FuGe.120, is placed on the R/T operator's switch panel, and is used in conjunction with the click-stop frequency selector for the E.Bl.3. 18. From evidence supplied by the present P/W it is possible to give a description of the Bernhardine display and of the exact data which it supplies. An impression of the Bernhardine display is given below; it will be seen that the printed tape is divided into three horizontal sections, on the uppermost of which appears a series of close vertical lines shortening at intervals to a "V", on the central section a reading in degrees, and on the lower a coded image which is the commentary. One simultaneous printing of these sections takes place during ten seconds of every minute, the tape remaining stationary for the remaining fifty seconds, after which the process is repeated. 19. In the lectures on Bernhardine it was stated that the ground transmitter makes one full revolution of 360° in sixty seconds; a section of the pattern of the ground transmission is repeated on the tape in the form of the series of vertical lines, the equisignal zone being represented by the apex of the "V". 20. In each printing lasting ten seconds a sector of 60° appears on the tape and in every case it contains a repetition of the equisignal zone. The reading in degrees appears in the central section of the tape in numbers representing 10's of degrees, and the point opposite to which the apex of the "V" is printed represents the bearing in degrees of the aircraft from the transmitter. Accuracy of bearings was stated to be within 0.5°. 21. A recognition letter is allotted to each transmitter and is repeated on the tape at every 20° on the scale; in the sketch the letter X - the recognition for the Leck transmitter is shown. 22. The commentary in the lowest section appears in each 10- second printing as a group of a maximum of ten letters and numerals, inclusive of two crosses denoting the beginning and end of a message. Should a message be of more than ten characters it wi11 be continued in the succeeding printing, a cross appearing at the end of the message. 23. Thus, the commentary message shown in the sketch, + 40 KA 27 100, just falls within the ten-character limit if the final + denoting the end of the message is omitted. The latter is therefore carried forward and appears at the commencement of the next printing; it denotes simultaneously the end of the one message and the beginning of the next. It was stated that a single message could be continued over three or four printings. 24. The commentary always appears in a standard order; analysis of the typical message shown in the sketch is as follows:- 25. It will be noted that the form of this commentary is exactly the same as that at present put out by the Divisions on the high powered W/T beacons (see A.D.I.(K) 599/1944 para. 57). 26. The present P/W had been told that, in addition to the Divisional commentary, instructions to individual formations of night fighters would be transmitted by the Bernhardine and printed on the lowest section of the tape. How, in such a case, the aircraft would be tracked or how the orders by the subordinate units would be coded, they did not know. Operational Use. 27. The aircraft set is switched on soon after take-off, so that the bearing transmitter can be constantly watched. If the + = beginning of message 40 = height of head of bomber stream in 100’s of metres KA = fighter-grid position of head of stream 27 = course of formation in tens of degrees 100 = estimated number of aircraft W/T operator wants the fix, he switches over to the transmission of a second Bernhardine station for a gross bearing; it was stated, however, that quicker and more favoured method was to obtain a simultaneous cross bearing from a high powered beacon through the PeilGe 6. 28. As far as these prisoners knew, only the Bernhardine stations at Berlin and Leck are so far capable of transmitting a commentary and flying instructions; the latter station was only modified in this way at the beginning of November 1944 and aircraft of 9/N.J.G.3 made several test flights, usually taking off from Uetersen at about 0230 hours and remaining airborne for some four hours. 29. The present P/W of 9/N.J.G.3 had not taken part in these flights, but after the tests he had seen the tape, which he described as being printed on white paper in red letter, 4 - 6 mm. high as clearly as with a typewriter. He was told that there was sufficient tape to allow of continuous operation for 4 hours 20 minutes. SIGNALS TRAFFIC. German Spoof Signals. 30. An aircraft of 7/N.J.G.3 shot down in Belgium on January 1st carried a signal order on which appeared the word "Orgelpfeife" (= organ pipe). Interrogation of all the present P/W elicited the fact that Orgelpfeife is the codeword for spoof R/T and W/T traffic passed between small numbers of aircraft and the ground with the object of simulating large numbers of night fighters in operation. 31. According to a P/W of 9/N.J.G.2 Orgelpfeife was introduced in that unit, in mid-November; one crew in the Staffel had received special briefing and usually operated the spoof traffic. In operating R/T spoof, this crew’s duty was to imitate a large number of night fighters operating by the simple expedient of all four members of the crew taking turns to speak, each using different callsigns. 32. It was said that the pilot of the crew in question, Oberfeldwebel GELLNER was something of an actor and was able to imitate various German dialects and different voices; P/W claimed that the single Aircraft could simulate as many as twelve night fighters. 33. The Orgelpfeife aircraft operated under Y control, since such importance was attached to its position in relation to the raiding force; the spoof aircraft patrolled an area near the estimated target and as the raiding force was approaching the target, the simulation of night fighters operating commenced. 34. According to P/W the spoof aircraft carried large quantities of Düppel (Window). 35. It seems that only one aircraft in a Staffel operates Orgelpfeife; this was certainly the case in III/N.J.G.2, and another P/W of III/N.J.G.3 stated that similar conditions prevailed in that Gruppe. 36. None of the present P/W could give any useful information on the method of coding the Orgelpfeife traffic, but it was stated that the briefing usually gave two codewords or groups, according to whether the spoof was R/T or W/T, and the crew was to ignore all orders from the ground except those preceded by the operative Orgelpfeife codewords or group. 37. In the captured briefing sheet mentioned above, the codewords for 7/N.J.G.3 on the night of December 31st were "Elfenbein" for the aircraft and "Hallore" for the ground. 38. A P/W of 9/N.J.G.3 stated that early in December R/T silence had been enforced amongst the normally operating night fighters of that Staffel. Defence of the Ruhr by N.J.G.1. 39. The four Gruppen of N.J.G.1 have been allotted the special task of defending the Ruhr in night attacks by R.A.F. Bomber Command, and to achieve this aim all the Gruppen are based strategically at airfields in that area. 40. In operations over the Ruhr the Gruppen are not controlled separately as would normally be the case, but operate under the central control of a special Geschwader commentary put out on a M/F and an alternative V.H.F. frequency; the latter, however, is almost invariably jammed. 41. This commentary consists of tactical instructions to the aircraft as well as reports on the general situation; according to P/W, the latter are not based on a Divisional picture of events, but on data supplied by the Ruhr Flak defences. 42. When a Mosquito force is reported over the Ruhr area, and providing that flying conditions are suitable, all aircraft of N.J.G.1 are put up and ordered to orbit any of the beacons Börse, Bruno, Achmed, Gemse, Heide, Schnake, Paule, Ratte and Drossel to await further events. 43. In case of jamming of both channels of Geschwader control, two of these beacons, Achmed and Paule, are set aside for transmission of the Geschwader commentary. P/W also heard that a further alternative H.F commentary is to be put out on a 20 kW transmitter whose signals will be superimposed on a Cologne broadcast programme. 44. The aircraft of N.J.G.1 usually orbit the beacons for about an hour, and if by then no attack by four-engined bombers has materialised they are recalled; upon returning to base, the aircraft are immediately refuelled so that should a further attack be made a fresh sortie can be initiated immediately. 45. In the middle of December some 50% of the aircraft in N.J.G.1 were equipped with two white LC.50 flares carried externally under the outer rings, and in the event of a major bombing attack on a Ruhr objective these aircraft were to make for the target and lay the flares at the operative height of the bombers, so that the remainder of the night fighters could quickly close in the area for visual attack. 46. The flare-carrying aircraft were to be given an X-time for arrival over the target to coincide with the arrival of the bomber stream; at this time the Flak would have orders to cease fire, the flares would be laid and the night fighters would go in to attack. 47. Importance was attached to the flare-carrying aircraft arriving exactly at X-time, since a previous arrival would put them and the remainder of the night fighters in danger of being shot down by the Flak, and a late arrival would jeopardise the operation. 48. In such a case where the aircraft of N.J.G.1 had been put up against a spoof attack of Mosquitos and a four-engined attack developed against targets outside the Ruhr, the Geschwader commentary would transmit the codeword "Diogenes", at which the aircraft would revert to their respective Gruppe commentaries and would operate against the new attack in the normal manner. 49. Crews of the flare-carrying aircraft were instructed that in defending targets outside the Ruhr they could use their flares, but only if they were certain of the true target. Jamming of Commentaries. 50. Prisoners of II and III/N.J.G.3 stated that the Gruppe commentaries were not seriously jammed in the Hamburg area; although R/T could occasionally be heard, however, crews relied mostly on the morse commentaries. 51. They stated that intensity of jamming varied considerably from night to night. They could not understand the reason for this since they had been officially told that the jamming had been D/F’d and traced to the London area. Verbandsführer (Formation Leader). 52. From the present P/W there are again conflicting reports on the success or failure of the system of flying in formation with a leader aircraft (A.D.I.(K) 700/1944, paras.34 – 49). 53. Whilst one P/W of N.J.G.3 stated that the system had been working well in that Gruppe up to mid-December and that leader aircraft operated under Y control, another prisoner, of 8/N.J.G.1, stated that in his unit the system had proved unworkable and had been dropped in October. He gave as one reason the dislike by the more experienced crews who flew as formation leaders of acting as flying beacons, with the attendant danger of being homed on by Mosquitoes. I.F.F. 54. Much has already been said about the FuGe.25a in recent A.D.I.(K) reports but nevertheless interrogation has continued as to the conditions under which the apparatus is or is not switched on during operations. One P/W of 8/N.J.G.1, based at Düsseldorf, stated that if no intruders were reported at the time the night fighters were ordered up for an operation, he would switch on the FuGe.25a at take-off and keep it operating until well clear of the airfield. 55. During operations he would have the instrument turned off, but on returning to base would again switch it on shortly before reaching the airfield - provided no warning of intruders was in force. 56. A P/W of 9/N.J.G.3 knew of the British air-to-air I.F.F. and knew that R.A.F. A.I. included a button which, upon being pressed, identified the friendly aircraft on the A.I. picture. 57. Crews in this Staffel were told that a German air-to-air I.F.F. was shortly coming into operation, but no further details were given. 58. A prisoner of 11/N.J.G.3 remembered having seen a note in a G.A.F. intelligence summary stating that the R.A.F. was using infra red air-to-air recognition. Hermine Beacons. 59. One of the present P/W had first heard of Hermine V.H.F. beacons in March 1944, and at the time had learned that these were radio beacons of new type from which pilots of singleengined aircraft could obtain bearings. 60. He stated that the beacon, which has an effective range of 200 – 300 kilometres, rotates through 360° in about three minutes. The beacon transmits a continuous tone over about 359° with a silence zone of 1° which sweeps through 360° as the beacon rotates; additionally a "speaking clock" counts continuously from 1 to 360 and the continuous tone is superimposed over this speech. 61. The pilot in the aircraft hears the continuous tone and the counting on the FuGe.16Z, but hears the bearing spoken clearly when in a line with the silence zone; he thus hears his bearing to the beacon. 62. It will be remembered that prisoners of the Wilde Sau single-engined night fighter unit I/J.G.301, captured in July 1944, had made mention of these radio beacons, albeit not by name. The Kommodore of a single-engined day fighter Geschwader had suggested that "Hermine" is derived from Oberst HERMANN, founder of Wilde Sau night fighting. INTERCEPTION EQUIPMENT. Spot frequencies of SN.2. 63. The word "Streuwelle" in conjunction with SN 2 has been mentioned for the first time by the present batch of prisoners. Although none was able to define the word Streuwelle or its origins, one suggested an alternative word "Frequenz"; A.D.I.(Sc.) has supplied an agreed translation of "Streuwelle" in the term "Spot frequency". 64. It has already been reported that in I/N.J.G.2 an attempt had been made to reduce the effects of electrical jamming by mounting the SN 2 aerial arrays diagonally instead of vertically. These prisoners confirmed that this had also been the case in other units, but the present interrogations have established that this arrangement of aerials has no connection with the spot frequency of the SN 2. In many cases prisoners have known the differing aerial arrangements to exist in several aircraft all equipped with SN 2's of the same spot frequency. 65. These prisoners knew of three Streuwellen at present in operational use, namely 4, 5 and 6; in two units, 8/N.J.G.1 and IV/N.J.G.3 some of the aircraft carried No.6, and other prisoners stated that aircraft of their units were equipped with 4 or 5 or a mixture of both. In 5/N.J.G.3, for example, Streuwelle 5 had superseded 4, whilst 8/N.J.G.1 was equipped with a mixture of 4 and 6, the latter having been delivered in October. 66. It is worth noting that aircraft equipped with Streuwellen 5 or 6 are forbidden to fly over enemy territory unless the boxes have previously been removed; no such security measures, however, exist with Streuwelle 4. 67. One prisoner had heard that a JU.88 equipped with SN 2 and Flensburg had landed at an airfield in East Anglia last summer and that the British were therefore in possession of an SN 2. He naturally assumed that the latter apparatus was of Streuwelle 4. Upon being asked how it was known that a German night fighter had landed in England he replied that the information had been given by British prisoners in Germany. 68. Not one of the present P/W could supply the respective frequencies of Streuwellen 4, 5 and 6, but the radar servicing mechanic P/W, who had been with N.J.G.4 up to the end of October, was able to give a few details of 4 and 5; up the time when he left the unit he had not encountered No.6. 69. He was certain that the frequency of 5 was slightly higher than that of 4; No.5 has one more induction coil and has a range exceeding No.4 by 5 kilometres, being provided with an extra switch giving two range pictures, one at 5 km. and one at 10 km. 70. He and other prisoners stated that no matter which Streuwelle, 4, 5 or 6, is installed in an aircraft, the aerial array remains unchanged and in all cases the same CRT's and the same electrical length of connecting cables are employed. 71. The ground radar mechanic stated that outwardly there is little difference between the three Streuwellen, and to avoid confusion by the ground staff all boxes have the appropriate number painted on the back; the boxes of different Streuwellen are not interchangeable. 72. An example of the effects of jamming on the differing Streuwellen was given by one of the present prisoners. In May 1944 all aircraft of his unit were equipped with Streuwelle 4 with provision for the alternative frequency. In July 1944, however, Window jamming made the set useless. 73. In October 1944 Streuwelle 5 and then 6 were delivered, both with the alternative frequency; these, however, were seriously jammed by the so-called Rauschsender (electrical jammer). It was found, however, that the remaining SN 2's of Streuwelle 4 were not so seriously upset by electrical jamming, and the result was that many crews asked for No.4 back again and their wish was granted. 74. According to the radar mechanic, the C.R.T's used in the SN 2 are manufactured by both Lorenz and Siemens Nürnberg; the latter are the more satisfactory in service. 75. One P/W had spent six months up to May 1944 installing SN 2's in Me.110’s at Werl; he stated that installation work for Ju.88’s was carried out at Gütersloh. Serviceability of SN 2. 76. Considerable trouble in the servicing of the SN 2 was experienced in misty or wet weather; the chief source of trouble was rain water percolating into the pulse distributor at the base of the antennae and was the cause of squints and the blowing of valves. 77. In units recently examined, night flying tests are no longer made; in the experience of one P/W of II/N.J.G.1 some 30% of the SN 2's were found to be u/s if the unit had been stood down for more than three or four days. 78. Should radar equipment be found to be u/s after an aircraft has taken off on an operation, the order is that the sortie must be completed. This is a state of affairs which rattles the crews, particularly if the SN 2 is not working and they are robbed of backward cover. SN 3. 79. As compared with prisoners captured up to the end of November 1944, the present P/W gave the impression that developments in the SN 3 have reached a further stage. 80. No prisoner has yet been encountered who has seen an SN 3, but several had heard some scraps of information. It was stated that the aerial array for this set is carried inside the aircraft, and that Major SCHMAUFER, Kommodore of N.J.G.4, is already flying an aircraft with this new search equipment. 81. There is no doubt that the Germans are in possession of details of British centimetre A.I. and it has recently been freely discussed by G.A.F. aircrew under the name "Grille" (= grid). TAIL WARNING. SN 2 Tail Warning. 82. The present P/W were able to add considerably to information obtained on night fighter tail warning equipment and set out in A.D.I.(K) 700, paras.13-16. The present interrogations, leave no doubt that the tail warners now extensively fitted to German night fighter aircraft are a part of the SN 2 equipment and that the picture appears on the SN 2 azimuth tube. 83. No height or bearing, but only a range reading can be obtained from the backward aerial; forward and backward displays do not appear simultaneously on the SN 2 tube, but the set is provided with a switch which can select one or the other. The method employed by the radar operator is therefore to search for contacts with the forward aerials whilst occasionally switching over to rearward aerial to see if an enemy night fighter is following. 84. A tail warning tactic recommended to crews of III/N.J.G.1 is one of not taking immediate action when a rearward contact is picked up, but of waiting until the range begins to close in. When this occurs, the pilot increases speed and if the blip closes in to 600 metres the pilot then takes evasive action. 85. In the above-mentioned unit evasive action has been ordered to take the form of a 180° hard turn to port or starboard. If the pursuing aircraft has been seen by the crew, the turn will be made according to its position; when the pursuer is to port, the pilot of the night fighter will turn in to port, or vice versa. 86. Previously, the tactics of the night fighter in those circumstances was to peel off towards the pursuing aircraft, but this resulted in losing 1500 to 2000 metres in height which took about ten minutes to regain. 87. The newer tactic described above was ordered in III/N.J.G.1 late in November to obviate this loss of height and time and in that unit at least, the tactic of peeling off is now forbidden except in extreme urgency. 88. A number of P/W knew the SN 2 tail warning as the D (or Dora) Zusatzgerät (= the Dora attachment). Fu.Bl.2 as Warning Device. 89. Yet another piece of German Airborne radio equipment, the Fu.Bl.2 has been added to the list of sets that are capable of giving a warning of approach of an aircraft. 90. Three P/W had heard that if the Fu.Bl.2 is switched on, the red marker beacon warning lamp lights up when a radarequipped aircraft is in the immediate vicinity. Naxos as Tail Warning. 91. Crews of 8/N.J.G.2 had recently been told officially that Naxos is capable of acting as a warning of the presence of enemy A.I.–equipped aircraft. No such information had been given to any of the other units examined during the present interrogations, and none of the other prisoners knew that Naxos had such capabilities. 92. It was pointed out by the one P/W concerned that Naxos can do no more than give warning of A.I. radiation on a given bearing, and range of the source of the radiation cannot be measured; a bearing reading would, however, at least indicate the probability of an enemy night fighter in pursuit. HOMING EQUIPMENT. The Naxos as an A.I. Instrument. 93. Since the first mention of Naxos by a prisoner in July 1944 (A.D.I.(K) 407/1944) and in the subsequent fuller account of other aspects of Naxos and its tactical use (A.D.I.(K) 508 and 620/1944) it has frequently been reported how some night fighter pilots have claimed to have used Naxos as an A.I. instrument. There have been frequent claims usually by lecturers at Werneuchen, that night fighter crews have shot down four-engined bombers with their upward armament without having used SN 2 at any time during the pursuit, but no prisoner has been encountered with first-hand knowledge of this fact. 94. Amongst the present P/W was a crew of 4/N.J.G.2 who had six victories, each with the help of Naxos to a greater or lesser extent. On five occasions they had located the bomber stream with Naxos and had made the final approach with SN 2. On the sixth occasion, however, they had shot down a fourengined bomber with upward armament after an approach with the sole use of Naxos. 95. In an attack on Berlin in March or April 1944, this crew took off from Twente and flew towards the Baltic coast. At about 54° 30' N; 11° 30' E some eight H2S contacts were obtained from a height of 4,500 metres; one of these was selected by manipulation of the Naxos brilliancy knob and followed to about 13° E and then southward over Berlin. 96. The contact was held and followed from Berlin towards Leipzig whilst the night fighter gradually approached its target by making contact with the edge of the H2S cone, throttling back to avoid penetrating too far and being detected, then climbing and again making contact with the cone in horizontal flight; a visual of the R.A.F. bomber was obtained near Frankfurt-am-Main when the night fighter was at a height of 7,800 metres. 97. The pilot closed in to make the attack but missed the bomber; after a second unsuccessful attempt, the rear gunner of the bomber fired a burst but missed. On the third attempt by the night fighter the bomber was hit and was claimed as a victory by this crew. 98. Early in October H2S contacts in the Naxos began to be fewer, and such contacts as were made invariably disappeared abruptly. The pilot who, incidentally, had a very high opinion of his own capabilities, put this down to his radar operator and blamed him for inefficiency; the result was that the crew was continually quarrelling and was engaged in heated argument when shot down. The Naxos Aerial. 99. The radar mechanic had been with I/N.J.G.4 had attended a Naxos course at Werneuchen in May 1944 and subsequently had had some experience in servicing the apparatus. The interrogation of this P/W on the subject of Naxos was carried out with the co-operation A.I.2(g), with the result that he was able to add some useful details to the substance of A.I.2(g) Report No.1734. 100. In August 1944, Naxos began to be delivered to 1/N.J.G.4. The Naxos-equipped Ju.88’s first delivered to the unit had the aerials installed on the after part of the fuselage, but in later deliveries, the plexiglass dome containing the aerials was fitted to the jettisonable hood of the cabin – a position known as "Ausführung A". It was feared, however, that the hood would be difficult to jettison and in some aircraft the original position of the aerials was again adopted. 101. When this P/W left I/N.J.G.4 in October 1944 the display unit in use was the Naxos-Post, but he did not know which type of aerial array was associated with this display, and he knew of no further designation of any part of the equipment. 102. When Naxos was first introduced to the unit, the aerials consisted of two plastic rods, of a material known as Trollitul, of square cross-section with rounded ends and measuring some 40 cm. in length and 5/6 cm in thickness. This type of rod was, however later superseded by one of circular cross-section with a diameter of 3-4 cm. and of the same length. 103. These aerials were fixed parallel to one another and about 3 - 4 cm, apart, being held in position at their central points by a bakelite clamp made in two halves. Rotation of the aerials was in a clockwise direction about an axis which was vertical when the aircraft was in flying position, the aerials cleared the aircraft skin by about 5 cm. Speed of rotation was estimated by P/W at about 3000 r.p.m. 104. The aerials were mounted on a vertical axle running in a ball Bearing flush with the aircraft skin and driven directly from an electric motor which P/W recognised as being similar to that illustrated in A.I.2(g)1734. 105. A copper lead came away from each plastic aerial rod and joined the axle on which the aerial rotated; between the ball bearing and the electric motor, a right-angle plug led the signals received by aerial out of the axle and through a length of single 1 mm. copper high tension wire to the Abgleichkasten (cable matching box). P/W had also heard the term "Hochpass Einrichtung" in connection with this box. 106. The cable matching box was shaped in cross-section like a half ellipse and measured about 25 x 8 x 8 cm. The screws securing the lids were sealed, and if any fault developed, the box had to be sent away to the Gruppe repair and servicing depot; the Staffel servicing staff were forbidden to break the seals. 107. This P/W had seen a box open at the Gruppe at the servicing depot and remembered that it contained a special type of coil and detector of a type similar to that shown in the A.I.2(g) Report. He was under the impression that there were six such detectors. Daily Inspection of Naxos. 108. The daily inspection of Naxos consisted of running up the aerial array on ground batteries and using an ordinary buzzer working from a torch battery as the transmitter. The oblong box containing the buzzer had to be held so that one of its ends, called the Strahlenseite (radiating end) pointed towards the aerial and was in their plane of rotation. A lightening of the appropriate part of the Naxos trace showed that Naxos was in order. AIRBORNE PLOTTING TABLE. 109. In the autumn of 1942 one at the present P/W had taken part in some flying trials of a television device which was being tried out at Werneuchen. For the purpose of the trials a television receiver which was to repeat an 18 cm. square picture of the Seeburg Tisch of a night fighter box, was installed in a He.111. 110. In the trials reception was remarkably good and a clear definition was obtained, the two spots of light representing the friendly and enemy aircraft could be seen, but the only means of distinguishing between the two was by the insertion of a cardboard arrow on the Seeburg Tisch. In a similar way cards bearing written vector instructions were placed on the plotting table in view of the camera. 111. At that time the Germans were experiencing no difficulties with box-control of night fighters and since continual troubles were experienced with the television transmitter the trials were discontinued toward the end of 1942. GERMAN H2S - THE BERLIN GERÄT. 112. The same prisoner had heard of a German version of the H2S called "Berlin" which he understood, was an improvement on the British apparatus. GERMAN KNOWLEDGE OF 100 GROUP R.A.F. Activities. 113. In lectures on night fighting given to 8/N.J.G.1, 7/N.J.G.2 and 9/N.J.G.3 in October and November 1944, crews had been given some details of the activities by 100 Group R.A.F. which gave them the impression that the German Higher Command has the greatest respect for the efficiency of those responsible for planning that unit's activities. Some details of these lecturers which prisoners from the above units could remember show that the Germans are now accumulating considerable knowledge of the equipment and tactics of 100 Group. 114. At recent briefings to 8/N.J.G.1 great importance had been attached to the part played by 100 Group, and the many occasions when warning of an impending attack had been given and the aircraft had been airborne only to find the advertised raid melt away, were now ascribed to the wizardry of that same unit. 115. It was stated that the Group is equipped with Mosquitoes and Lancasters - amongst whose crews were some expert bombers - and that both these aircraft types carry the jamming equipment which together with ground jammers upset the commentaries and the SN 2. Long range intruders were also ascribed to the same unit. 116. In a lecture on 100 Group given to 7/N.J.G.2 early in November 1944, crews were told of so-called 'D' aircraft which has the duty of putting out spoof R/T and W/T instructions to German night fighters; one instance was related in which a whole night fighter Gruppe had returned to base as a result of spoof orders by one of these D aircraft. The W/T operators at the 1ecture were advised that if they paid sharp attention to their R/T and W/T signals they would be able to distinguish between the false and genuine instructions. 117. It is now widely known by G.A.F. night fighter aircrew that Mosquitos are equipped with a search equipment, the Grille (= grid), that has a range of 15 kilometres (about 10 miles) and is said to work on a frequency of 3 cm. An interesting extra piece of information given in these lectures was that Grille was capable of homing on SN 2 transmissions, a point that was noted by crews with some consternation. A.D.I.(K) and S.D. Felkin U.S. Air Interrogation. Wing Commander 27th January 1945" |
Underground factories for Junkers aero-engines.
"SECRET A.D.I.(K) Report No.151/1944
THE FOLLOWING INFORMATION HAS BEEN OBTAINED FROM P/W AS THE STATEMENTS HAVE NOT AS YET BEEN VERIFIED, NO MENTION OF THEM SHOULD BE MADE IN INTELLIGENCE SUMMARIES OF COMMANDS OR LOWER FORMATIONS, NOR SHOULD THEY BE ACCEPTED UNTIL COMMENTED ON AIR MINISTRY INTELLIGENCE SUMMARIES OR SPECIAL COMMUNICATIONS. UNDERGROUND FACTORIES - NIEDERSACHSWERFEN AREA (July 1944) 1. The following information on underground factories in the Niedersachswerfen area was obtained from the Dutchman, who was the subject of A.P/W.I.U. (2nd T.A.F.) 3/1945. Representatives of A.I.2(a) and A.C.I.U. were present at the interrogation and due thanks are rendered for their co-operation. 2. According to informant's story he began to work for the Germans in January 1942, when he was employed as a labourer by the 0.T. in connection with the electrical installations on Lorient airfield. Thanks to diligent work, spare-time study, judicious bribery and his self-assertive nature, he claims to have risen rapidly in the world and to have acquired something of a reputation both as an electrical engineer and as a reliable satellite of the Germans. 3. After working as a foreman electrician on the Dutch coastal defence works between Flushing and Den Helder, he was given the task of supervising the installation of electrical equipment at the Vught concentration camp. Finally, he asserts that at the beginning of 1944 he obtained employment on the staff of S.S. Gruppenführer und Generalleutnant der Waffen S.S. Dr. Ing Kammler (see A.D.I.(K) 522/1944), who was entrusted with the task of constructing important secret underground aircraft and armament factories. 4. According to informant's account, Kammler placed him in charge of the Abteilung Energieversorgung of Amt C.III of his staff, which was charged with supervising the provision of electric power to underground factories in course of construction under the aegis of the S.S. 5. In this capacity, informant stated that in June 1944 he was sent to Niedersachswerfen to arrange for the provision of electric current to a number of underground sites which the S.S. proposed to construct in the area, but at the end of six weeks he was called away to undertake similar work at other projects at Litomerice (Leitmeritz), Czechoslovakia, which will be dealt with in a separate report. 6. It was apparently intended that he should return to Niedersachswerfen on 1st December 1944 but before that date he had decided, for motives best known to himself, to desert the S.S., and in due course he arrived inside the Allied lines. 7. As the well-known underground factory at Niedersachswerfen itself was already working at the time of informant's visit, it did not fall within his province and he only entered it on one occasion. His information on this factory was therefore disappointingly meagre, but he was able to make some general remarks on the Niedersachswerfen complex as a whole which, although based on impressions gathered during a short stay, sound reasonably plausible. 8. As regards the function of the already native Niedersachswerfen plant informant could not enlarge upon existing knowledge. He was aware that Junkers were installed and thought they were making "the turbine for the V.1 and V.2". General. 9. According to informant, no less than seven underground factories were projected by the S.S. in the Niedersachswerfen area, and the project as a whole was known as Bauvorhaben X. 10. These sites comprised the already active factory at Niedersachswerfen, the Woffleben site which was numbered B.3. and on which construction work had already started by Ju1y 1944, another site some 800 yards to the North West of the Woffleben one to which the code name "Nie" had been allotted, and four other projected sites numbered B.8, 3.9, B.11 and B.12 of which informant pinpointed two. 11. It was pointed out that the letter 'B' stood for Bauvorhaben and that in theory the number indicated the original order of priority in which it was intended that construction work should be undertaken. 12. Informant stated that all seven sites in the area were destined to be occupied by Junkers and that all the plans were drawn up by Ing. Spott, the chief construction engineer of the parent Junkers works at Dessau. The factories, however, formed independent units in that there were no underground connections between the various sites. 13. The scheme was carried out under the supervision of S.S. Sonderinspektion II, who were responsible for the provision of labour and materials and, of course, security precautions, but the actual construction work was in charge of the "Wifo" organisation, a fact which may explain rumours which have connected the Niedersachswerfen project with P.O.L. storage and or production. 14. The S.S., however, provided technicians to assist in the construction cork and they also installed their own agents, such as informant, in order to exercise a general supervision and to keep an eye on developments. There was said to be continual friction between Junkers, who desired the best possible standards of accommodation, and the S.S., who insisted that the utmost economy must be exercised in every respect. 15. According to the planned schedule, the six new factories were to be ready for occupation by February 1945 but in informant's opinion they would not be able commence work before July at the earliest, chiefly owing to the difficulty of obtaining transformers. 16. In July 1944 the original Niedersachswerfen factory was of course in operation, and construction work had started at Woffleben, where informant thought that work had begun on two tunnels, and possibly also at the site 800 yards to the North West of Woffleben. 17. In August 1944 the underground sites at Litomerice were given priority over the projects of the Niedersachswerfen area, but informant did not know whether this was on account of the urgency of the activity to be accommodated at Litomerice or because of the greater rapidity with which these latter projects, which largely occupied existing workings, could be pushed forward. Niedersachswerfen. 18. As P/W had only been inside the Niedersachswerfen complex on one occasion he could only give a very general and not particularly reliable impression of its internal layout. He confirmed a previous informant's statement that the workings consisted of two main tunnels serving a number of workshops, but thought that the workings, though quite level, were not straight, and that the standard gauge railway line did not run into the tunnels. 19. He had noted that the entrances were strengthened with concrete reinforced by railway metals, and that inside the galleries weak places were also reinforced with concrete for distances of up to 100 metres in some cases. He could make no statement on overburden. 20. Informant believed that in the floor of the galleries there were a drainage channel one metre wide and another channel 75 cm. wide for the piping of the air conditioning system. Some of the power cables were installed in third channel in the floor and others, together with the wires for the lighting and the telephone cables, were carried on iron supports along the walls of the galleries. 21. Informant believed that a power supply of 600 kW was required to run the air conditioning plant and that the capacity of the Niedersachswerfen stand-by plant was insufficient for this. He therefore believed that, if normal supplies could be cut off, the air conditioning system would necessarily cease to function and that the galleries would start to drip, with disastrous results to the virtually irreplaceable machine tools. Woffleben. (B.3). 22. In July 1944 the Woffleben site enjoyed the highest priority of the six new projects envisaged in the Niedersachswerfen area. At this date two entrances giving access to two parallel main tunnels running roughly N.W. - S.E. through the hill were said to have been started, and several subsidiary galleries running off the main tunnels had also been commenced. It was believed that considerable difficulty was being met with on this project owing to underground springs and streams encountered in the course of the excavations. 23. It was believed that when construction work was completed the site would be taken over by Junkers for the manufacture of aero-engines. Woffleben West ("Nie"). 24 The project 800 yards North West of the Woffleben workings and designated by the code name "Nie" was the last of the Niedersachswerfen sites on the official priority list but, strangely enough in July 1944 it was the only site besides Woffleben on which construction activity appeared likely to begin in the immediate future. 25. One entrance only was planned, and this was to be located at the south-western corner of the hill. This entrance was to give access to the main tunnels running the length of the hill, and these tunnels were to be connected by a network of some 40 or 50 cross-galleries. A servicing gallery was to run round the whole site in order to facilitate transport; the workshops were to be arranged to give a production flow running northwards from the entrance, the finished articles being collected at the northern end of the site and brought round to the entrance by the servicing gallery. 26. This factory also was earmarked for Junkers, but informant had no reliable information as to the purpose for which it would be utilised. In July 1944 instructions were given to extend the existing power cables as far as this site, so that construction work could be commenced. Ilfeld. 27. Besides the above-mentioned sites, another underground Junkers factory was planned in the hills a short distance to the West of the village of Ilfeld some two miles North of Niedersachswerfen. The entrance was to be in the vicinity of 110360 GSGS 4416 Sheet Q5, and this was to serve a complex of galleries arranged on the conventional grid pattern. In July 1944 construction work had not begun but a small group of contractors' huts had been put up near the proposed entrance. Appenrode. 28. Although informant knew that a total of seven underground factories was envisaged, the only other projected site which he was able to identify was in a hill between the villages of Appenrode and Ilfeld and to the North of the road connecting the two. It was understood that the entrance would be located in the neighbourhood of 087361. 29. In July 1944 two contractors' huts had been put up on the site but at that date construction work had not been started and power cables had not been brought up to the area. Power Supplies. 30. Informant alleged that in July 1944 all power supplies both for the already active Niedersachswerfen factory and for construction work at the other sites was supplied exclusively by the 110 kV line from the Bleicherode power station. At the new sites the 110 kV line was to be led directly into the tunnels and the transformers intended to serve the factory machinery were to be installed inside the workings, and informant understood that this system was already obtained at the Niedersachswerfen factory. 31. It was intended that when other sites came into operation, power would also be supplied by a new 110 kV line running from a power station at Frose in the Magdeburg area to Woffleben, where it would join the grid serving the underground factories in the Niedersachswerfen district. As in the case of the existing line from Bleicherode, the power was to be stepped down in the Niedersachswerfen complexes to 20 kV and 6 kV in the first instance. 32. According to informant's story, the power stations at Bleicherode and Frose would therefore be the sole sources of electricity supplies for the underground plants around Niedersachswerfen. He explained that it was not intended to draw on other sources partly on account of the load already carried by other power stations and partly because of the acute shortage of materials needed for the construction of transmission lines which made it necessary to rely on generating stations located reasonably near the factories. 33. The new line from Frose was said to be intended to run South-West across country from Frose for about one third of its length and thence almost due West to Woffleben. The most direct route was chosen in order to effect the greatest possible economies in cables and pylon. 34. In July 1944 the holes for the pylons had been excavated and sufficient pylons were on hand at the Frose and for completing about one quarter of the proposed line. In the following month, however, some of those pylons were requisitioned for the Litomerice projects, which in the meantime had been given a higher priority, and some of the new pylons on order were also later diverted to Litomerice. 35. The contract for supplying the pylons was held by the firm of Seidl of Falkenstein (Vogland) who were said to be able to deliver three daily. Emergency Power Supplies. 36. Unfortunately informant did not claim to be conversant with the emergency power supply system in the Niedersachswerfen complex. He stated, however, that he understood that it conformed to the general instructions on the subject issued by Generalleutnant Kammler on 1st August 1944, and he had the foresight to bring with him a photostat copy of the document in question. 37. In his instructions Kammler draws the attention of his Sonderinspektionen and S.S. Führungsstäbe to the fact that the emergency power plants proposed by these bodies are of excessively high capacity. He adds that as a measure of fuel economy emergency plants are only to serve such appliances as necessary for the safety of the personnel, i.e. lighting, water supplies end air conditioning. 38. The two last-named systems are to be confined to the absolutely necessary minimum and Kammler formally forbids the connection of any normal equipment to emergency generators. 39. Future demands for emergency sets are to show the capacity of the act divided into the requirements for lightening, water supplies and air conditioning. The projected requirements for lightning are to be cut down to the necessary minimum since, if the normal supplies of power fail, normal activity will cease ipso facto. For the same reason, good grounds are to be shown for the maintenance of air conditioning and water supplies during the period when normal power is cut off. Railway Services. 40. The plans for the Niedersachswerfen complex of underground factories provided for a now ring railway connecting E11rich, Ilfeld and Nordhausen and serving the whole of the sites. For the convenience of workers proceeding between their quarters and their place of work as well as between the various factories, a train was to be run every three minutes on this line. 41. In addition, a large marshalling yard was envisaged on both sides of the village of Woffleben and on both sides of the existing Nordhausen - Ellrich line. Personnel. 42. Appendix I contains a list of some of the principal personalities connected with the Niedersachswerfen complex of sites. Construction work at Woffleben was being carried out by inmates of the Buchenwald concentration camp under the supervision of "Wifo" personnel. 43. When all the factories were in operation it was expected that they would employ a total staff of some 45,000 workers. In July 1944 some personnel was already billeted in Ellrich and Nordhausen and it was rumoured that when the various sites came into production these towns and the area surrounding them would be evacuated to provide accommodation, especially for married employees and their families. A.D.I(K) and S.D. Felkin U.S. Air Interrogation. Wing Commander 5th February, 1945. APPENDIX. SECRET. PERSONALITIES CONNECTED WITH UNDERGROUND ACTIVITY IN THE NIEDERSACHSWERFEN AREA S.S. Gruppenführer und Generalleutnant der Waffen S.S. Dr. Ing. H. Kammler. Entrusted by Himmler, in his capacity as the head of the S.S. Wirtschaftsverwaltungs Hauptamt, with the execution of the Deutsches Geheimbauprogramm, which comprised important secret underground factories. Head of the so-called Stab Kammler which was created for this purpose (see A.D.I.(K) 522/1944). S.S. Hauptsturmführer Dipl. Ing. Geissen. Head of S.S. Sonderinspektion II, which was charged with the supervision of construction work on the sites in the Niedersachswerfen area. S.S. Sturmbannführer Fleto. Head of Amt C.III (Technische Fachgebiete) of the Stab Kammler and in this capacity in charge of the technical side of construction work. Sturmbannführer Skowronneck. Head of the Abteilung Maschinen of Amt C.III of the Stab Kammler. A subordinate of Flote and responsible for the provision of the necessary machinery. Major Regierungsbaurat Dr. Dr. Ing. Trautvetter. In charge of the section of the S.S. Wirtschaftsverwaltungs Hauptamt responsible for the provision of materials. Dr. Neu. "Wifo" representative in charge of construction work in the Niedersachswerfen district. Ing. Schwatz. Chief "Wifo" engineer at Niedersachswerfen. Ing. Reinzhagen. "Wifo" engineer in charge of the electric, gas, heating and air conditioning equipment. at Niedersachswerfen. Ing. Spott. Chief Junkers constructional engineer. Responsible for the plans for all the Niedersachswerfen sites. Dipl. Ing. Pönitsch. Junkers constructional engineer responsible for electricity, gas and similar supplies." |
Luftwaffe morale
"SECRET A.D.I.(K) Report No.157/1945
THE FOLLOWING INFORMATION HAS BEEN OBTAINED FROM P/W AS THE STATEMENTS HAVE NOT AS YET BEEN VERIFIED, NO MENTION OF THEM SHOULD BE MADE IN INTELLIGENCE SUMMARIES OF COMMANDS OR LOWER FORMATIONS, NOR SHOULD THEY BE ACCEPTED UNTIL COMMENTED ON AIR MINISTRY INTELLIGENCE SUMMARIES OR SPECIAL COMMUNICATIONS. LUFTWAFFE MORALE. (August to December 1944) 1. This report is an endeavour to assess and analyse Luftwaffe aircrew morale in the period of five months from 17th August 1944, on which date a similar assessment was made in A.D.I.(K) 473/1944. The number of aircrew prisoners interrogated for the present review, amounting to 246, comprises the largest sample since 1940. 2. The majority of these prisoners have been tough and well drilled in security; at no point did the proportion with high morale fall lower than 51% and, as may be expected, the period when it reached this lowest ebb was during the German withdrawal in August. Since then, the proportion of high morale amongst all aircrew has risen steadily until, in December, it was found to stand at 64%, with day fighters even higher at 74%. 3. It should be noted that the present report deals throughout solely with aircrew morale and that ground personnel are not taken into account. The morale of the ground personnel, judging from recent samples, is just the same as it has been for a long time – bad. THE BASIS OF MORALE. 4. The basis of G.A.F. morale remains very much the same as before, and can be said to consist of a mixture of the following factors: the natural discipline of nearly all Germans, youth, love of flying, patriotism and a general ignorance of the real facts of the war. It is true that aircrew have very few amusements and almost no time off, but they continue to live fairly well; in fact, better than any other section of the population. They experience no hardship comparable to that of the front-line soldier, and they receive on the whole less bombing than either the army or the civilians. 5. Expectations and promises for the future play a large part in maintaining morale and still continue to be believed. As one fighter-pilot said: "In the autumn we were guaranteed 2,000 new fighters. They have turned up, and this makes me prepared to believe that the other new weapons and aircraft promised will also turn up". However small the "come back" of the Luftwaffe might seem to the Allies, it has helped the ordinary German pilot to believe that the inventors and technicians still have the situation in hand. The promise of large numbers of jet aircraft for the spring has had the same effect. 6. Many, though a decreasing number, of the younger P/W still profess belief in ultimate German victory, a belief which is quite unconnected with any logical process of thought whatever, but depends on what can only be termed as mystic belief in German invincibility. This faith is no doubt fostered by the good fight they are putting up in spite of the enormous difficulties caused by bombing and the shortage of so many necessities inside Germany. 7. It cannot be said there is much desperation in their courage. Rather is it a quiet resignation to the fact that they have no alternative to fighting on. Certainly the impetus derived from fighting on German soil against unconditional surrender helps to counteract strain and war weariness; but although attempts have been wade by German propaganda to instil a kind of "Battle of Britain" spirit, it is doubtful whether it has succeeded. 8. One of the smaller props to morale has gradually been upset. When the Luftwaffe was in its prime, outstanding aces were carefully built up as heroic types, an example to others. This hero-worship, to which the Germans are so addicted, was encouraged to what we would consider an inordinate degree. But by now most of the aces have been killed and others, like G GALLAND and PELZ, no longer fly on operations and are even accused of becoming out of touch with the operational personnel. At the same time the camaraderie between officers and men has become less. 9. The new appeal is based more on staple patriotism and fear of the consequences of defeat. A frequent propaganda theme is: "Life will not be worth living after the war". The horrific picture of a conquered Germany, easily concocted by GOEBBELS from unofficial Allied pronouncements, is well calculated to make men fight to the bitter end. 10. Much greater than fear of defeat at the hands of Britain and America is dread of Russia. "Sieg oder Sibirien" - Victory or slavery in Siberia, is a slogan which has a considerable effect, an effect not unconnected with a sense of guilt for what Germany has done above all to the populations in the East. Manly realise that such wrongs avenge themselves, but nevertheless justify their conduct by persuading themselves that they are upholding a higher civilisation. 11. Among aircrew less resentment of our bombing policy is felt than might be expected. The destruction of so much of both private and public property and fine cities, however, not to mention the casualties involved, helps to foster a certain feeling of futility about the future, and even a wish to escape it. Thus in some ways continued resistance is a putting-off of an evil day - with the small, but to them worthwhile chance that the Allies might quarrel, the German technicians produce a trump, and defeat might be avoided in a triumph of defensive warfare. A STATISTICAL ANALYSIS OF MORALE. 12. The three tables presented below show morale at time of capture; the assessments are those made by the original interrogators on the Continent, and differ slightly - almost always for the better - from the assessments given at the end of A.D.I.(K) reports in which allowance is not always made for the weaknesses which develop under prolonged interrogation and in the isolation of theme from the sustaining effect of his group. (a) Period August – November 1944. August Morale. Type of Unit. No. of P/W High. Fair. Low. Bomber 22 12=55% 6=27% 4=18% Day Fighter 14 6=42% 6=42% 2=16% Others 7 4 - Total 43 22=51% 15=35% 6=14% Average age - 23.3 years. September - November Morale. Type of Unit. No. of P/W High. Fair. Low. Bomber and transport 18 + 11=61% 2=11% 5=28% Day Fighter 10 7=70% 2=20% 1=10% Night Fighter and N.S.G. 15 8=54% 2=13% 5=33% Others 2 2 - - Total 45 28=62% 6=13.5% 11=24.5% Average age - 23.3 years. + This figure includes the only bomber crew captured between 16th August and 18th December; this crew comprised the three survivors of a V-1 launching He.111 which ditched in the North Sea on 6th October. Notes on the above Tables. (1) Even in the catastrophic days of August, 51% of the Luftwaffe aircrew captured showed good morale, and of the rest 35% could be said to have fair morale. 2) Although the sample is too small to be satisfactory, it is perhaps significant that the morale of the crews of heavy aircraft retrained steadier than that of the fighter pilots which, however, recovered more quickly. (3) The absence of any marked defeatism in the Luftwaffe directly after the attempted Putsch of 20th July and the catastrophe in France indicates the extent to which its personnel are imbued not only with a sound fighting spirit but with esprit de corps. Though of an age which has only known a Nazi upbringing, flying personnel of the G.A.F. are not very politically minded. Loyalty to the regime which has done them personally no apparent harm, and which has often benefited them, is strong, as there is no substantial alternative. (4) The fact that there was a virtual debacle in the air at the same time certainly had a depressing effect, but there was always the excuse of overwhelming superiority on the Allied side. Furthermore, promises were made that a great new fighter force would be formed and a new training, programme was put in motion. It was believed by many that the new jet-propelled aircraft would enable the Luftwaffe to make a startling come-back with qualitative superiority. In fact the 0.K.L. reacted to the new situation with vigour which gave a new hope to a depressed but eager-body of young airmen; whose mental horizon is as limited by flying as it is by propaganda and education. (b) Period December 1st 1944 - January 1st 1945. 14. By the end of November 1944 it seems that the German Air Staff considered that the Luftwaffe had been sufficiently nursed back to health to be employed on a large scale in tactical support of the Army. At the same time, in the absence of an adequate bombing force, night-fighters were sent in considerable numbers in an attempt to cause dislocation over the Allied lines at night. The result has been the largest batch of aircrew prisoners, since the Battle of Britain. 15. The morale of the 158 P/W, assessed as before at time of capture, is analysed as follows:- State of morale Type of unit N° of P/W High Fair Low Average Age Day Fighter 80 59=74,5% 14=17% 7=9% 22.9yrs Night Fighter 54 28=52% 19=35% 7=13% Others, incl. Bombers,transport and recce crews 24 14=58% 8=33.5% 2=8.5% 23.2yrs Total 158 101=64.6% 41=26.5% 16=10% 23.0yrs Notes on the above Table (1) The over-all improvement in morale seems very slight against the previous three months. This steadiness is in contrast to the fluctuation noticed in 1943 during the same period, i.e. between the low point reached with the landings in Italy and the defection of BADOGLIO, and the recovery connected with the bogging-down in Italy and the beginning of reprisal raids on England. Unfortunately the method of assessment was not identical with the present one and the samples much smaller but it is interesting to note that in the period September to mid-November 1943 the percentages of high, fair and low morale were found to be 61% 31% and 5%, while in the period mid-November to January 1944 they were 83%, 17% and nil. (2) The only marked improvement is among day fighter pilots, whose morale has jumped from 42% high in August to 74% high in December. This has been due (a) to careful husbanding of strength for a big effort. (b) the maintenance of the fighter aircraft industry in spite of Allied bombing and (c) the successful defence of the frontiers of the Reich. (3) While these three factors also apply to the whole of the Reich defence force, the morale of one branch, the night-fighters, has noticeably declined although they are better trained and more strictly selected, and not long ago were the most steadily successful part of the Luftwaffe, they show an inferior spirit to the day-fighters. One reason for this is that they have an increasing sense of frustration, caused by jarring of signals channels and interception equipment and frequent failure owing to "spoofery" to contact bombers at all. They also show a high level of intelligence, which does not help morale. They may fly blind, but they think less blindly about the war. (4) The majority of these P/W were captured during the RUNDSTEDT offensive and before they were plainly aware of its failure. That it could be launched at all gave, a certain fillip to morale. (5) The fighter unit showing the most consistently good morale is J.G.4, with J.G.2 coming second. (6) It would be wrong to consider all those with morale assessed as fair to be only fair fighting material. In a unit with a high spirit - which applies to most - they would be carried along with the majority, and would hardly be aware themselves of the chinks in their armour. (7) Fewer P/W are found to have listened to Allied broadcast propaganda than at any time during the last 18 months. This is partly due to the fact that most are fighter pilots, as opposed to bomber crews as in the past, and live in less permanent quarters, and partly because morale itself is higher. THE EVENTUAL UNDERMINING OF MORALE. 16. Interrogators on the Continent who see P/W in the first days after their capture have found them extremely tough almost without exception. In so far as the time taken to break down a man's security is an indication of his fighting spirit and not of improved security instruction, morale is higher than it has been for some time. It is, however, not so deeply ingrained. P/W to-day are not only slightly younger than in the past, but each time they come from a later age-group. This means they are more unformed. Fewer are intelligent and more are bone-headed, and the eventual undermining of security, and later of morale, is made easier by this fact. With them security is often merely an induced state with automatic reactions rather than intelligent attempt to continue fighting although a prisoner or war. Once it breaks they tend to talk freely. This applies chiefly to N.C.O.'s and other ranks. 17. With most younger officers the basis of the high morale is somewhat different. They attempt to explain their professed faith in victory, which for them amounts to avoiding defeat, on the score of superior fighting ability, V-weapons etc. But they also tend to be less fact-proof and easier to reach with argument, though only with much time and trouble. Older or senior officers, who know more facts, are nearly always prepared to admit that Germany has lost the war, but their discipline and sense of responsibility clearly keeps them from showing any defeatist spirit to the men under their command. 18. It is nevertheless startling to find how different is the attitude of most P/W after a week or so of being moved from place to place and being interrogated. During this time they learn with their own eyes or from the people they meet a great many unlightening facts and some truths; they have time to reflect on the tremendous material superiority of the Allies which they see behind our lines; if they happen to pass through London, this especially brings home to them the swindle of their own propaganda. 19. The young generation in Germany has so long been denied the possibility of finding out the other man’s point of view that when he gets the chance of doing so he frequently discovers he cannot answer it. This is a weakness of which interrogators have learnt to take advantage. If a patient and serious attempt is made to open a P/W's eyes to the facts he has been denied, for him the GOEBBELS machine begins to operate in reverse. 20. This very susceptibility of Germans to propaganda might suggest that their re-education after the war may not be so difficult, but it should be remembered that the interrogators achieve little more than a rather static "deconditioning and with the assistance of depressing circumstances. Any eventual "reconditioning" must depend on a new dynamic of ideals, and social and political loyalties, which are at present all too painfully absent. CONCLUSION. 21. It would seem that since morale is not built on reason, but on blind faith, loyalty and patriotism, it will only break down when facts or a conflict of ideas, successfully undermine the original basis. In so far as these destructive influences operate at all in the field, the whole of German propaganda is working, not unsuccessfully, to exclude them. As a result aircrew on capture continue to show good fighting spirit. 22. Morale did not slump seriously during the disastrous days of the summer, and does not become unduly depressed by failure or heavy losses, or even as a result of land reverses. This suggests the conclusion that taking flying personnel in the Luftwaffe as a whole, morale will not break as long as they have aircraft and petrol, the army continues to resist, and they themselves are told to go on fighting. A.D.I.(K)& U.S. Air Interrogation. S.D. Felkin, 8th February 1945 Wing Commander" |
Re: Researching the Luftwaffe through Prisoner Interrogations
Fascinating, especially by U.S. Air Interrogation.
|
Re: Researching the Luftwaffe through Prisoner Interrogations
ADI K 065 5/NJG 101 Ju 88.
Junker |
Interrogation of Baron Von Schalcky CIOS File 24-15
"(49) A.L. No. 19 (Sheet 2) 29/9/45
Interrogation of Baron Von Schalcky CIOS File 24-15 JAGDSCHLOSS The original plan for Jagdschloss provided three models covering the following frequency ranges; 75 to 120 Mcs; 120 to 160 Mcs. Jagdschloss A was actually operated between 130 and 160 Mcs, with a frequency change requiring only five seconds. This frequency change was among a choice of four pre-set frequencies in which the proper dial settings for transmitter, receiver, and TR-antenna coupling systems were indicated with special markers. The antenna was designed to work over a two to one frequency range with the limit set by tactical requirements rather than by standing wave ratio. Jagdschloss was first used in April 1944 and by February 1945 it was felt that the Jagdschloss coverage of Germany was complete and with considerable overlap. The normal usage of Jagdschloss was described as "Luftlage"; that is, it was used for early warning and to maintain a watch of all aerial activities. It was used in this capacity to assign targets to either ack-ack control or GGI installations and, as noted below, was used directly for fire control under some conditions. The maximum range ever obtained on a Jagdschloss was said to be 250 kilometers on an 8th Air Force formation. Ranges of 180 to 120 kilometers could be obtained normally. However, these ranges were obtained with the A scope which was normally used for tuning and testing purposes. In normal operation for Luftlage, the range of Jagdschloss was limited by the 120 kilometer sweep length on the Sternschreiber (P.P.I.) In the Berlin area on several occasions during August and September 1944, Jagdschloss data was used directly for fire control. This was done by assuming the altitude shown by our bomber formations to be a constant which was found statistically to be quite an acceptable assumption. Then the range and azimuth of the formation was obtained by Jagdschloss and appropriate data was transmitted to the flak batteries. The battery then fired a controlled barrage, setting the fuzes in such a way as to cover about 2,000 foot altitude spread. The Baron said this procedure was considered very effective against our 8th Air Force bomber formations. Incidentally, the Baron was well acquainted with our division of bomber activities and was familiar with 8th Air Force organisation and procedure. Jagdschloss was fitted with a remote transmission system which transmitted the Sternschreiber picture up to 150 kilometers OVER WIRE TRANSMISSION LINES. No specific mention of direct use of this facility was made. Several Jagdschloss radars were in various stages of development: One of these sets was the 50 cm set on which the PW had been running tests. This was another Jagdschloss by Siemens Company. In addition a 25 cm set of similar characteristics had been developed by Telefunken and was known as Forsthaus F. This set used a conventional type tube in the transmitter known as Scheibenröhren. The details of its construction were not known to von Schalcky. A 9 cm. Jagdschloss set, known from other sources as Forsthaus Z, was also in development by Telefunken. The PW indicated that Forsthaus was the Telefunken name for "Luftlage" radar whereas Jagdschloss was the name used by Siemens. The effort on these radar developments was to obtain higher discrimination so as to provide less susceptibility to Düppel. Von Schalcky was of the opinion, however, that going to narrower beams, although it provided a smaller pulse packet and thus higher discrimination, caused sufficient loss of target return due to the shorter length of time that a target was illuminated as the radar antenna rotated, to set a limit to this technique. His reasoning is probably correct if one considers the low peak powers used in precision German radar. The PW also had the opinion that the higher frequency sets (above 1000 Mcs) were less satisfactory for early warning due to what he called "Troposphere" reflections. Several anti-"Düppel" (anti window) measures had been developed and were being tested on the 50 cm. Jagdschloss. It was interesting to note that the procedure was to utilize 8th Air Force Window for test purposes rather than bothering to drop their own. 1. Phosphor clearing device. This was a simple expedient which was made necessary by a characteristic of the Sternschreiber phosphor. Apparently the decay time was so long that Window echoes would tend to build up large, fully, illuminated areas giving a sort of compound jamming effect over a period of time. The expedient was to turn off the beam for one or two rotations of the antenna system and to radiate the screen from an infra-red source during this off period. The existing echoes were thus erased. Equipment for doing this automatically was just being completed. 2. Film frame comparison method. Exposure of two successive frames of the Sternschreiber presentation were made on the same piece of colour film. The exposure for frame A was made with a red filter and exposure frame B was made with a green filter. Each rotation required six seconds, thus the total exposure required 12 seconds. The equipment for doing this job had been developed and built by Zeiss. The existing development model had been destroyed by von Schalcky at Heidhof. The equipment was arranged so that one minute after the exposure, the colour film could be projected on a screen. Due to the additive effects of green and red, fixed echoes appeared as black marks or "streams". However a moving target in which the succeeding exposures were displaced in accordance with the motion appeared as a "beetle" having a green head, black center, and red tail. The green, of course, points in the direction of motion. Von Schalcky distinguished between heavy 8th Air Force daylight window and thinner RAF Window. Heavy Window gave definite black areas or "streams". However, Window occurring in small separated clumps sometimes gave the effect of motion due to the random shifting of dipole orientation with consequent random displacement of the effective center of the Window cloud. This effect was considered a disadvantage of this particular A/J system, the principal aim being to enable distinction of fixed and moving targets. 3. A frame storage moving target indicator method was being developed and had undergone preliminary tests. An iconoscope mosaic storage was employed. The Baron did not think that this method used coherent pulse. The same disadvantage of the difficulty of distinguishing between aircraft and small clumps of Window was encountered as in the case of the photographic method. 4. Siemens was developing an adaption of the Laus or coherent Doppler to Jagdschloss, the intention being to alter the display of moving targets on the Sternschreiber, allowing fixed echoes to be presented normally. A third detector circuit derived a pulse signal from the beating Laus of a moving target. This pulse was applied to the radio deflecting system in such a way that moving targets tended to trail in towards the center of the tube as shown in the sketch below. The Sternschreiber tube had a double phosphor similar to our P-7, in fact, adapted from the P-7. The flash trace is blue but in the Sternschreiber the afterglow is green and apparently of longer duration than our yellow. Von Schalcky did not know the chemical details of this phosphor. He thought a persistence of ten minutes was obtained. Comment was made that our daytime 8th Air Force jamming was picked up often on the 50 cm. experimental Jagdschloss and that it was never possible to see aircraft in the jammed sector on the Sternschreiber. B. Freya. The Dreh Freya was considered very inferior to Jagdschloss for general search and coverage because of the serious nulls in the vertical antenna pattern. The modification of the Freya Laus, known as "Windlaus", was designed to enable cancellation of any particular Doppler beat caused by wind drift of the Window. Two oscillators were used, one to lock the transmitter frequency and a second for comparison in the receiver. The frequency of the receiver oscillator could be adjusted independently so that a particular Doppler frequency produced no output, thus wind-blown Window echoes would not appear as a Laus presentation, whereas fast moving aircraft would still be detected as moving targets. This was said to be in use on a considerable number at Freya installations. The use of centimeter listening receivers, either, on Freya mounts (as at Kothen airfield) or in separate installations, was quite common as an early warning system for detecting the approach of H2S or H3X. C. Fire Control Radar. The PW stated that the Würzburg Frequency spread was 63 to 50 cms (476 to 600 Mcs). He stated this twice, and was rather positive on the point. Gustav is a code name for Würzburg Riese G and consists of Freya radar added to the normal Riese. Freya equipment is located in the far end of the can necessitating very slight alteration in the normal layout. Two antenna arrangements are in use, in one a single vertically polarized radiator one wave length long being mounted in front of the normal Würzburg antenna and using the normal Würzburg reflector to obtain a measure of directivity. The second arrangement utilizes two dipoles one on each side of the normal antenna, again vertically polarized. Von Schalcky did not believe that reflector elements were used with this antenna arrangements and that the Würzburg dish was the only other element involved. In addition to Riese G, there was a variation with a broadband Freya installation known as the Riese G-la. The use of these combinations as understood by this PW was simply to aid in putting the Würzburg on target. He did not believe they were used for range, only A/J. The Mannheim was preferred over either Würzburg for tracking in normal conditions but it was considered less effective in the presence of jamming than the Würzburg. This was attributed to the ability of a good operator to interpret a jammed scope on the Würzburg, a procedure impossible in the Mannheim meter presentation. It appeared the Mannheim scopes were not usable where jammed. The use of aided tracking on the Würzburg D, on the Riese, and on the Mannheim, was common as a measure against jamming which was not effective all the time. A fixed tracking rate could be set in by the operator. Von Schalcky did not know of any centimeter fire control sets. D. Fire Control Procedure With regard to predictors used for fire control computation, von Schalcky knew only of the KG-40. He understood that the preferred SOP was to use optical direction and radar range in all possible circumstances including night operations. In this connection, the small Würzburgs were used for searchlight control, the optical system built in the KG-40 being then applied for final direction finding. Using the Riese, he thought it was nearly always possible to obtain slant range in the presence of our jamming. He felt that the KG-46 was still the most widely used predictor in the GAF defense system. Use of Wurzburg Riese and Riese G's for fire control was said to be quite common and extensive. A procedure for utilising data from several different radars as in the Gross-battery was mentioned. In this, a specially trained operator surveyed Selsyn relayed data from the several radars associated with the battery and mentally selected and averaged the best appearing data. That is, if two radars were producing roughly the same information but a third was giving different indication, he would utilise the data from the two more consistent sets, delivering this information by phone to the KG-40. With this installation, which was said to be fairly common, it was thus possible to change instantly from one radar to another for control purposes. In a defense area such as a city or other specific target, all defenses were controlled from a central Kommand post. A Jagdschloss was associated with this Kommand and was used in assigning targets to ack-ack or fighter defenses. In addition, Wassermann or other height finding radar would usually be associated with the Jagdschloss. In the case of fire control, if the battery was unable to track an assigned target because of jamming, it was usually instructed to fire a barrage on the basis of Jagdschloss data. In a few cases, arrangements were made for relaying information between adjacent batteries by phone but the P.W. did not believe this to be as common as the practice of using Jagdschloss data. Provisions for automatic transmission of data between batteries had been worked out but were not in common use. E. GGI Procedure. Naxos had been in use since April 1944 for homing on British H2S radar. The practice of triggering our IFF from both ground and air installations was common and, it was felt, quite successful. Also few night fighters had recently been fitted out for triggering what must have been Oboe Mark II in the RAF planes. Automatic Seeburg was not liked as well as the manual because of the roughness of the data plotted when a radar would "spring" or deviate from the true tracking course. A manual table allowed smoothing in the process of manual plotting. F. Allied RCM. As-noted previously our jamming was not considered effective in jamming range on the Riese. However, against Würzburg D and Mannheim, the combination of Düppel and Störsender was quite effective, especially after October 1944. Screening of Freya was more effective in night than in the day time but was never considered a serious effort. This PW had the understanding that screening was also directed against Jagdschloss and knew of cases where Allied planes had circled a Jagdschloss site continuously during operations in that vicinity. The overlapping coverage of Jagdschloss made it possible nearly always to obtain the necessary information, though a particular set was out. The maximum range of Jagdschloss as used operationally was 120 kilometers. G. Centimeter antennas. The PW knew of the poly-rod antennas used in Naxos and the use of a parabolic reflector copies from H2S. The parabolic reflector antennas were chiefly by Siemens. One other type of centimeter antenna of interest was a slotted wave guide as shown in the sketch. The slot is tapered to provide uniform radiation from all sections of its length. This was Telefunken development, known as Holstraehlen. (47) A.L.No.14 (sheet 20) 24.9.45 Magnetrons & Klystrons Interrogation of Drs. Kleen, & Lerbs by Mr. Griffing, Major Ravenel, F/Lt. F. R. Holt. (Evaluation Report 139) Dr. Kleen was head of the Telefunken Tube Research Laboratories, recently at Berlin. Dr. Lerbs was in charge of the Magnetron group under Dr. Kleen. Most of the German centimeter tube development has been made in these laboratories, which were for some time in Liegnitz. The first 10 cm. equipment. "Rotterdam" was operational between 6 and 12 months ago; since then further marks of this (known as X1 and X2) also "Berlin" and "München" have been developed. The magnetron used, LMS 10, was a copy of the allied one. The 3 cm. ones produced were claimed to be their own development. The LMS 10 was 30% efficient. The LMS 100 up to 100 kW, also on 10 cm. was 10% efficient and had a field of 1500- 2000 Gauss, 30% greater than critical. It was air cooled and was suitable for space/mark of 1000. The LMS 12 on 3 cm. had 18 splits, the L.M.S was 3 cm. tuneable, and water-cooled, with 2 kW loss. Small receiver magnetrons are the RD2MG (3 cm. 6 or 8 splits, 50 kW output, short life), the RD2MH, and the RD4MG, This series contains about 10 other types. They have only used Copper Magnetron anodes recently, have had trouble with glass sealing (usually Nickel-iron soldered to the copper with Silversolder was preferred), and have only recently found a satisfactory method of pumping the LMS 100. For power measurements up to 10 watts, they used the heating effect on a resistance wire forming part of the Wheatstone bridge; above that, water-flow methods. Most of the tunable Magnetron work was done on 3 cm. They used a metal ring supported on a flexible membrane and moved towards the circle of gaps. Some magnetron development was done by Sanitas GmbH, and possibly the Reichspost at Heidelberg. They were produced by Telefunken at Berlin and Reichenberg in Eulengebirge, and also by Sanitas and Getewent. Most of the work on Klystrons was done in Prague by Dr. Labos of the B.H.F., Telefunken have made 3 cm. all metal (that is, main body) Klystrons and have been experimenting on 1 1/2 cms. These are reflected beam tubes. The following ceramic and metal grounded-grid triodes have been made:- LD7, LD9, LD11, LD13, LD70, LD90, LD110, a development of LD10, LD120, LS1000, and a diode of similar construction LG11. (They prefer however use a crystal detector up to 20 cm. LD12 was used in "Berlin", and LD11 in "Euclid" a 27 cm Navy equipment. With the triodes they have obtained 10 kW peak power with a space/mark from 5 to 10. This was of course in jammers. Names of jammers mentioned were "Anti-Boomerang" i.e. Oboe "Anti Rotterdam" i.e. H2S and any equipment with name beginning with "Feuer" e.g. "Feuermolch" and "Feuer-Zauber". These jammers are said to have been used operationally in small numbers (10 to 20 equipments.)" |
UNDERGROUND FACTORIES IN GERMANY
"ITEM N° 21,22,31
FILE N° XXXIII-36 SECRET UNDERGROUND FACTORIES IN GERMANY Reported by C.I.O.S. Party 536 (L) HAMMERWERKE FACTORY, near Hausberg Porta Westfalica, Minden This factory, of the multi-storey type, was constructed in underground quarries on the East side of the Weiser gap south of Minden. The quarries were situated in the Porta Sandstone above the Dachs I Refinery, and had been enlarged by the Gewerkeschaft Porta to house the Phillips Radio Valve factory from Eindhoven, in Holland. Constructional work is said to have started in March, 1944 and to have been completed in September, 1944. Production started in February, 1945. Contracts The following were interrogated- Herr Goosens, engineer, Dutch, speak English. Herr Pott, mining engineer, manager of the Gewerkeschaft Porta. Herr Haupt, formerly engineer on plant installation now custodian of the factory for the military Government Geology The geology of the area has already been described in the sections dealing with Dachs I and Denkmal Stollen. The Hammerwerke factory nine storeys high was constructed in the Porta sandstone (photograph No. 21) and being south of Dachs I was at a higher level as a result of the dip of this stratum as can be seen in the geological motion attached to this report (Fig. 8A.) The two factories were to have been connected by an internal shaft. There was no evidence of rock falls in the factory area. Lining & Support The workings were for the most part unsupported and the rock surface only whitewashed. At a few points steel joists and timber laggings had been used. Excavation The little excavation done on this site was carried out simultaneously with Dachs I and no separate data was available on labour, costs or progress. Entrance The main entrance, on the seventh floor, was protected by a blast wall of concrete 1.1 metres thick, and was connected with the main road at Hausberg by funicular railway. Water Supply Process water was pumped from the River Weser. Water was available from the town supply. Sewage Disposal Sewage was disposed by gravity into the Weser after treatment. Air Attack There was no evidence of air attack on this site. Engineering Services (a) Heating The Boiler House was located on the surface at road adjacent to the entrance of the Porta (Dachs I) factory. The boiler was of the horizontal type in three sections:- 1. Cornish boiler design with corrugated flue. 2. Section comprising smoke tubes. 3. Smoke box section. Steam was taken off the middle section, which was also provided with dead weight safety valve, and thence proceeds to the super heater section located round the crown of the smoke box. Steam and condense mains were taken through the entrance of the Dachs I factory and thence by means of a sloping tunnel up to the ground floor of the Hammerwerke Factory and to the various steam heater batteries associated with the ventilation plants. (b) Ventilation Six separate plenum extract systems were installed all of similar character and dealing with the floors in groups. Each system draws fresh air from, and discharges vitiated air to, the cliff face. Each inlet system comprised a main inlet fitted with a wire grill leading into a concrete spray chamber thence to an eliminator and finally to the fan chamber. The water sprays were not connected, but it was clear that they were to be supplied with water from the main supply and that this water would be rejected to waste. Two types of delivery fan were used:– 1. Double inlet type in an enclosed fan chamber following spray and eliminator chamber. 2. Single inlet fan with duct connection to the spray and eliminator chamber. Each inlet fan discharged into a main delivery duct constructed in building board, at the respective ceiling level, and vertical metal ducts were taken down to floors as required with adjustable discharge openings near each floor level. Vertical extraction ducts with inlets at high level, as required, were connected to a main extraction duct, also constructed in building board, running adjacent to the corresponding main fresh air delivery duct. The main extraction duct was connected to the extraction fan chamber and thence to atmosphere. At the time of the inspection all fans were running but heater batteries and water sprays were out of commission. Condensation was evident on the lower floors but the general state of the factory suggests that production heat energy in conjunction with the use of steam heater batteries had resulted in a reasonable air condition. (c) Electric Power and Lighting The electric supply was taken from the sub-station at Porta (Dachs I) at 6,000 volts and the high tension cables were brought up through the service tunnel and taken to four transformer stations. The voltage was than transformed from 6,000 volts to 400 volts 3 phase 4 wire, each of these transformers was rated at 800 KVA. Low tension feeder cable were taken as risers to metal closed cabinets containing main switches, fuses, circuit breakers and relays. Circuit wiring was taken at high level and in general was supported by a series of galvanised multi-strand steel cables which also served as earthing wire collectors. Each steel cable was thoroughly bonded to the rising watermain. Drops to machines and table inspection lights were taken from special metal junction boxes with porcelain interiors. All metal parts and components were earthed on to the galvanised straining cables by means of single strand cables, approximately No. 18 gauge. An attempt was made by interrogation to gain information regarding the type of earth leakage system installed but the only information offered was that every power unit had a leakage trip and that transformer were earthed at the star point. The general illumination and local bench lighting were of a high standard for example 4 kilowatts of lighting load has been installed in an inspection bay approximately 25' x 25'. (d) Fire Protection Fire hydrants complete with hose reels were provided in metal cabinets fixed to walls and connected to the rising waterman. Portable fire extinguishers were also provided. (e) Gas Installation Gas for process work was obtained from the town supply and the installation followed conventional standards for the class of work under consideration. Production and Layout This factory consisted of nine floors with layout as shown on the attached print and situated in the same hill as the Oil Refinery, Dachs I, which is the subject of a separate report. This factory was first put into operation in February, 1945 when it was intended to reinstate the production hitherto obtained from Philips Eindhoven factory, Holland. All plant and equipment even down to the inspection benches and stools were transferred from Eindhoven. This factory was very impressive in so far that there was ample spacing, and lighting was particularly good. The ultimate production was to have been 12,000 radio valves per day, but it was ascertained that up to the date of ceasing production, some 7,000 serviceable valves only had been issued. This in no way represents the total number of valves actually manufactured since it was made clear by the Production Engineer (Dutch) that the number of defective was considerable and this in the main was due to inclusion of dust at the final assembly stages. It should be appreciated that this dust trouble would not be discernible by casual observation. Nevertheless, the question of dust did not apparently interfere with the manufacture of component parts nor did it affect work carried out in the tool room and maintenance shop. Walls had been whitewashed but not otherwise treated or lined. The total labour force spread over three shift would have been 1,200/1,400, the vast majority being female, mainly young Jewish girls from concentration camps. Three shifts were arranged via:- two of 6 hours, and one of 8 hours, the break coming between 3.0 am and 7.0 am. Production arrangements were as follows :- lst floor - Toolroom and general maintenance shop. This plant was in first class condition, amply spaced and machines were of first class make, including several American tools such as Gorton and Milwaukee Milling machines. This floor also housed the gas production mixing plant required in production and was distributed to the required stations on the other floors by normal pipe distributing system. 2nd floor - This was essentially devoted to grid rolling and all the requisite plant for this operation had been installed and its condition was good. 3rd floor - Allocated to component assembly. This floor was also used as a main stores for component parts. 4th floor - Mainly for assembly and testing. 5th floor - This was laid out for the drawing of filament wire. and testing, but it was obviously not yet in full production. A side gallery on this floor was occupied by a separate firm, Carsten of Hamburg, who were apparently responsible for stamping out the mica parts which were subsequently used by Philips in the assembly. 6th floor - Had no defined use at the time of visit, except for a few offices and it was understood to have been used as sleeping quarters. 7th floor - This was the main entrance and exit for the whole factory, and contained a certain amount of plant for preparation of cathodes and filaments. 8th floor - Preparation of cathodes and filaments. 9th floor - This was used for offices and ablution, and had a small exit probably used by staff only. Access for employees to the respective floors was by stairway, and for goods, a lift 4 x 3 metres and having a capacity of 5,000 kilograms was installed to serve floors 1 to 7. The only external access provided to this factory from the main road was by means of a funicular railway which terminated at the level of floor 7 and about 200 ft. from the tunnel entrance." |
G.A.F. INTELLIGENCE IN THE WAR
"SECRET A. D. I. (K) Report No. 394/1945
THE FOLLOWING INFORMATION HAS BEEN OBTAINED FROM P/W AS THE STATEMENTS HAVE NOT AS YET BEEN VERIFIED, NO MENTION OF THEM SHOULD BE MADE IN INTELLIGENCE SUMMARIES OF COMMANDS OR LOWER FORMATIONS, NOR SHOULD THEY BE ACCEPTED UNTIL COMMENTED ON AIR MINISTRY INTELLIGENCE SUMMARIES OR SPECIAL COMMUNICATIONS. G.A.F. INTELLIGENCE IN THE WAR – II. Sources and Dissemination of Intelligence. 1. This, the second report of the series dealing with G.A.F. Intelligence during the War, is based mainly on the interrogation of Hauptmann ZETZSCHE who, during the Period of Major WODARG's office, was in control of Gruppe A of the department "Foreign Air Forces West" under Chef Ic. 2. The infuriation set out in this report falls into two main headings of "Sources" and "Publications". The paragraphs dealing with the German "Y" Service as a source of intelligence have been purposely reduced to a minimum, since a series of eight reports covering that subject alone is to be issued shortly by A.D.I.(K). SOURCES OF INTELLIGENCE. FOREIGN AIR FORCES WEST. 3. The department of Foreign Air Forces West, under Major OWE (see A.D.I.(K) 393/1945, Appendix IV) and with a staff of about 100, was responsible for covering Great Britain, the Empire, the U.S.A., France, Switzerland, Spain, Portugal and the Middle East. 4. The two Gruppen of the department "A" and "B", dealt respectively with military aspects and political and economic questions. In spite of the far greater commitments of Gruppe A, departmental strength was equally distributed between the two Gruppen. 5. The following are the sources upon which Foreign Air Forces West depended for collation of intelligence. German "Y" Service. 6. The German Y-Service - Abteilung 3 of General MARTINI's staff – supplied collated data to Chef Ic. In spite of Generalleutnant SCHMID's complaints of that department's methods of working (see Part I para. 31), Hauptmann ZETZSCHE stated that this source provided extensive data for Allied Order of Battle, subordinations and chains of command, operations, radar developments and ferryings of aircraft from the U.S.A. 7. Four sub-sections of Abteilung 3 covered all aspects of Allied activities, and issued daily intelligence summaries which were telephoned or teleprinted to Chef Ic. Ten-day and monthly appreciations of Allied activity were also issued, the latter containing valuable Statistics of Allied incursions. 8. One section, Chi-Stelle (codes and cyphers) Referat B covered all radio and radar intelligence on the western front such as details of current air operations, including Gee-H and Oboe attacks. The southern front was similarly covered by Chi-Stelle Referat C, and a sub-section, Referat C-1, dealt with Allied transport and ferrying traffic, this latter was of special value to Ic in assessing Allied production and losses. 9. Radar intelligence from both Western and Southern fronts was collated by a section known as Funkleitstand. A monthly report was issued which was of great help to Ic in assessing Allied radar and the effects of German jamming. A liaison officer was maintained by Funkleitstand with the P/W Interrogation Centre at Oberursel for the purpose of clearing up obscure points by interrogation of Allied aircrew. 10. Another section, the Zentrale Funkaufklärung (ZAF) was set up at Treuenbrietzen for tactical evaluation of radio and radar data received in the area of Jagdkorps I. As this section was solely concerned with tactical considerations, its relations with Chef Ic were not close. Prisoner of War Interrogation. 11. Excellent results were obtained from the close co-operation with Auswertestelle West - formerly Dulag Luft; collated reports resulting from detailed interrogation of Allied aircrew provided valuable matter for Ic publications as well as for filling in gaps in Order of Battle, etc., left by the "Y" service, and supplying the Y-Service itself with working data. 12. The actual methods employed by the Germans in the interrogation of their prisoners has been set out in detail in A.D.I.(K) 388/1945. It is perhaps worth recording that Oberst WODARG was frequently caused no little embarrassment as a result of Generalleutnant SCHMID of Jagdkorps I being on the distribution list for P/W interrogation reports; SCHMID usually had his copy first, and WODARG found it disconcerting to have to tell GOERING things he already knew. Air Reconnaissance. 13. The G.A.F. strategic reconnaissance effort was limited by lack of fast aircraft types. During the period leading up to the invasion, reconnaissance of England by day had been practically nil; at the end of May 1944 two Me.109's succeeded in carrying out a probing reconnaissance of the Isle of Wight under cover of cloud and an American four-engined sortie. The invasion fleet in Southampton was covered only once - whereupon a night attack by Fliegerkorps IX followed. Beyond a few isolated daylight efforts, reconnaissance results consisted entirely of night flash bomb cover - mainly valueless - and visual reconnaissance by Me.410's. 14. With the introduction of the Ar.234 subsequent to the invasion, the situation improved steadily. Airfields, harbours, London etc. could then be effectively covered. Nevertheless there were still too few aircraft (three names of pilots only were to be read on aerial photographs), and the enemy picture obtained continued to be only a partial one. This state of affairs was partly due to the emphasis placed on tactical reconnaissance, the results of which were of interest only to the Army and G.A.F. operation commands. 15. Scientific evaluation and appreciation of aerial photographs by Ic was made difficult through bad organisation, the G.A.F. Hauptbildabteilung being subordinated to the General der Aufklärungsflieger. Fremde Heere West (Foreign Armies West) and 3 S.K.L. 16. Ic placed great value on the information on Order of Battle, subordinations and directions of thrust of Allied ground forces supplied by Fremde Heere West, which for its own part found the Ic enemy air situation report extremely useful, in that the Order of Battle of air ground support units showed a clearer cut and timelier picture of enemy intentions than the movement of military ground forces. 17. Fr.H.W. issued extremely good appreciations. Alone with Ic/West it pointed continually to the probability of one sole landing on the Normandy coast, in opposition to the firm Wehrmachtsführungsstab belief in the likelihood of a second landing in the Straits of Dover. 18. Intelligence received from 3.S.K.L. the Naval liaison unit, was for the most part scrappy, owing to the dearth of information regarding the occupation of Allied harbours and the distribution of the Allied navies, landing craft and merchant fleets. Reports from Operational Commands. 19. Ic officers at the front complied only partially with Chef Ic's requirements, owing to a variety of reasons, such as Chef Ic's lack of personal influence, the sometimes poor quality of the Ic officers themselves, and the emphasis placed at the front on the reporting of the enemy’s actions rather than on knowledge about him, such knowledge being merely designated as enemy propaganda. 20. The main teak of Operational Command Ic's was to teleprint to Ops. Staff In a current enemy situation report, comprising Order of Battle, operations, tactics and any special considerations such as possibilities of air landings, invasion eta. These reports were, however, only forthcoming at irregular intervals and even then seemingly with an ill grace. Thus, with the exception of the Luftflotte 3 Ic appreciation prior to the invasion, Front Ic reports could not be considered as a regular source of intelligence comparable with Auswertestelle West or the W/T Listening Service. 21. A further duty was also neglected by Ic's at the front, that of passing up Staffel reports to Chef Ic and passing down Chef Ic reports to the Staffeln. Instead, every month each Operational Command painstakingly produced its own comprehensive report of the air situation carefully printed and edited and covering enemy incursions, operation., Order of Battle strength, subordination., etc., the figures naturally differing between one Command and another, and from those of Chef Ic who had other sources at his disposal. 22. As for the sources available to Operational Commands, on which the reports were based, Oberstleutnant OHLETZ, one-time Chief Intelligence Officer of Luftflotte 6, gave the following as sources available between January 1941 and March 1943:- i) The Luftflotte tactical and strategical reconnaissance units. These were at the disposal of the Ic as and when required. ii) A signals intercept unit for the Luftflotte 6 area. iii) The interrogation centre for Russian flying and Flak personnel. iv) A photographic unit. v) Evaluation of battle experience of Luftflotte 6 units. vi) A captured equipment evaluation centre. vii) Current data from adjacent Luftflotten. viii) Reports from Ic-Heer, supplied by the Army Group Centre. ix) Reports from the Military Intelligence Service affecting Luftflotte 6 area. 23. OHLEZ states that results of a tactical nature were distributed by him to Luftflotte 6 units. Full details were sent to O.K.L. Ic and Army Group Centre, and brought to the daily conferences of the Flottenchef with his Chief of General Staff and officers in charge of operations. 24. It is therefore not difficult to understand why Operational Command Ic's with such resources at their disposal and in view of their special operational commitments, should feel themselves independent and to some extent intolerant of control by Chef Ic, and why Chef Ic on his side, with responsibility for the accurate assessment of the full enemy situation, and viewing the situation solely from this standpoint, should maintain that Ic's at the front were overstaffed and negligent of their true functions. Evaluation of the Press. 25. Each Intelligence organisation in Germany made its own arrangements for the procuring and evaluating of foreign newspapers and periodicals. Chef Ic obtained its papers either through the R.S.H.A. or the G.A.F. Air Attachés in Bern, Stockholm and, up to 1944, Madrid, Lisbon and Ankara; Papers were at least four weeks out of date when received owing to poor R.S.H.A. organisation. American newspapers and periodicals were received only occasionally and in small numbers. Luftwesen was responsible for supply within Ic, and thus provided a further cause of delay. 26. Intelligence was extracted from press reports concerning personalities (e.g. from "Aeroplane, "Tatler" and "Sphere"), production figures, photographic material, tactics and economics matters. Technical Intelligence. 27. Enemy aircraft armament was covered mainly by Chef Technische Luftrüstung section A/Rü, and Ic could neither guide nor co-ordinate its work. Generally speaking, A/Rü took upon itself to keep industry and Operation Commands informed, Ic serving to pass its reports down to unit level. 28. These reports mare very good and complete, but came much too late to be really valuable, since TLR-Rü invariably waited until the last details were known on any subject before issuing a report upon it. For the same reason Ic only received at long and irregular intervals reports on Allied aircraft shot down. Broadcast Monitoring. 29. Of special interest and value were the broadcast links between the news agencies and their correspondents in the various capitals of the world. Of broadcasting stations, the B.B.C. and Swiss stations were considered the most reliable, Daventry in particular being appreciated for its figures concerning Allied sorties and losses. Indeed, during the period between the invasion and collapse, BBC reports were often the only source of reliable information on the war situation. 30. Radio monitoring was done by O.K.W.-Chi, its Naval counterpart the Seehausdienst, and the Forschungsamt, the results being sorted out and distributed by Ic/Luftwesen. Agents. 31. The complete failure of the German Agent Organisation as a source of reliable information was attributed by ZETZSCHE to the following causes:- i) The unsuitability of personnel both at home and abroad. ii) Lack of agents in high positions. iii) Many agents inspired by British Intelligence, e.g. Hector, Josephine probably, and Ostra for certain. iv) No agents in America. v) Agents' reports evaluated and issued without reference to Ic, final judgment on them being passed by Abwehr I/Luft (later R.S.H.A. Mil.Amt). vi) The splitting of the Agent organisation between Haupt Amt IV and Haupt Amt VI of the Mil.Amt, thus giving rise to two separate organisations abroad. vii) The final assumption of control by the S.D. causing the whole organisation to fall to pieces, and the flow of useful reports to cease altogether. 32. Liaison was maintained with the Militärisches Amt through Oberstleutnant von DEWITZ. From the middle of 1944, however, agents' reports were not passed out to Commands owing to their proved unreliability. Attaché Reports. 33. Attaché reports came from Amtsgruppe Ausland (Admiral BÖRKNER) of O.K.W. which passed to Ic important reports from military, Naval and G.A.F. attachés, as well as direct from Air Attachés in neutral countries, organised by the Ic Attaché Gruppe. 34. For the most part attaché reports consisted of descriptions of economic conditions and morale abroad, sometimes amounting to no more than translations of newspaper reports. Little of any value was ever received concerning England, France or U.S.A. On the other hand attachés often swallowed whole rumours issued by the Allies for German consumption, e.g. rumours concerning the imminent invasion of Norway, the Balkans, etc. 35. Air attaches were not held in very high esteem partly owing to their being considered poorly chosen for the task and partly owing to lack of firm direction by Ic (Luftwesen). Diplomatic Reports. 36. Reports from the Foreign Office and agencies abroad came to Ic both through Amtsgruppe Ausland of O.K.H. and through the Ic Liaison Officer with the Foreign Office, Hauptmann EHRENHAUS (Ic/Luftwesen/Pol). They were of little military value. 37. Intelligence concerning foreign diplomatic exchanges was received from the Forschungsamt (subordinated directly to GOERING) through Ic/Luftwesen/Abwehr, and was given a restricted distribution. It consisted of intercepted Allied radio-telegrams (e.g. London-Stockholm), ordinary radio reports (e.g. Atlantic Radio) and intercepted traffic between diplomats and ministers on certain links, Ankara-Moscow (Turks), Bern-Washington (Americans), London Washington (Poles). 36. The last-mentioned source was of great value before and during the invasion and after the breaking-off of Turkish-German relations. In general the Forschungsamt reports contained a great deal of significant information concerning economic and political matters. Reports from Repatriated Germans. 39. The Army, Navy, G.A.F. and Gestapo interrogated at will both military and civilian repatriates. A general lack of direction and coordination resulted. Auswertestelle West, Oberursel, was responsible for the G.A.F. interrogations and obtained many interesting details on enemy morale and supply. FREMDE LUFTWAFFE OST (FOREIGN AIR FORCES EAST). 40. This section, the eastern front counterpart of Fremde Luftwaffe West, covered the Soviet Union, China, Sweden, Finland and the Balkans. It was organised into the following subsections:- i) Aufmarsch. In this section the Russian Order of Battle was worked out in the greatest detail. Since the bulk of the Soviet Air Forces was employed tactically in support of the Armies at the front, this work was of the utmost scope and importance. Appreciations of the air situation were issued whenever necessary, on average every three to five days. Maps showing the locations of Soviet flying units were issued on the 1st and 15th of each month. ii) Training and Organisation. This section covered Soviet subordinations and chains of command, the organisation of Soviet flying schools and the training of pilots. iii) Archives. This section was responsible for provision of target data. It covered Soviet Industry, power plants, oil installations, ball bearing factories, etc. It issued industrial reports, based mainly on P/W statements and W/T intercept material supplied by the Forschungsamt. iv) Auswertestelle Ost (Evaluation Centre East). This organisation differed from Auswertestelle West in that it dealt only with the most important and knowledgeable prisoners, as for instance the Russian Inspector of Fighters who landed with his staff by mistake on a German airfield in 1943. Thirty to forty P/W at the most were at Auswertestelle Ost at any one time. The remainder were dealt with by the interrogation centres of the individual Luftflotten, which reported anything of interest daily. Since the Listening Service provided the complete Soviet Order of Battle, and knowledge of Soviet tactics was deemed unimportant, P/W were only kept for what information they might provide concerning Soviet organisation. Auswertestelle Ost was located near Karlsbad and was under the command of Oberstleutnant MOLTERS. MELDEWESEN. 41. As the receiving and distributing centre for all data concerning German and Allied operations, Meldewesen constituted an information bureau highly appreciated by its users, i.e. O.K.W., O.K.L., GOERING, Operational sub-areas, etc. The limited communications and staff of Ic were however, insufficient to cope with the stream of enquiries from HITLER, GOERING, Chief of General Staff and the rest, so that the flying units were perforce neglected and the very success of this section tended to have a detrimental effect on the work of Ic as a whole. LUFTWESEN. 42. This department was an unhappy attempt to co-ordinate a number of widely differing functions. It comprised the following sub-sections, some of which have been already referred to:- L/Abwehr, which was responsible for the maintenance of security within the G.A.F. and for the security training of the flying units. For the first task it did not dispose of sufficient personnel, and as already indicated, Fremde Luftwaffen West and Ost were the only departments competent to carry out the second. However, from the middle of 1944 an Oberleutnant ROLFES was appointed liaison officer with German P/W camps with the object of exploiting the intelligence possibilities of this source. L/Pol. Maintained Ic liaison with the Foreign Office. His main effort was to produce his "Aussenpolitischen Wochenbericht", a weekly report on the political situation, reflecting Foreign Office views and mainly emphasising the reasons for an Anglo-American-Soviet Russian conflict of views. L/Informationsdienst sorted and distributed radio reports sent in by O.K.W./Chi. L/Presse received reports from the Army, Field Propaganda companies etc. as well as foreign publications. Liaison with the S.D. was provided by Major MERKWITZ and Hauptmann BULA. Attaché Gruppe. Owing to the total lack of accommodation in Berlin, the close direction of Attachés by Luftwesen was made impossible and their control virtually ineffective. INDEPENDENT SPECIALISTS. 43. Ic Wirtschaft. In this section Oberstleutnant SEIDL, with the assistance of one officer, issued a monthly report on Anglo-American bombing attacks, comprising details of damage, falling-off of production etc. and predicting probable future Allied tactics. Ic/See. This department covered purely Naval matters. Ic/Bild. Theoretically for the purpose of Ic-liaison with the Main Photographic Section, this department was rendered superfluous owing to the practice of subordinate units by-passing Ic and dealing direct with the Hauptbildabteilung. PUBLICLTIONS ISSUED BY Ic. 44. The succeeding paragraphs in this report are in the form of a catalogue of publications issued by Chef Ic. Hauptmann ZETZSCHE's assessment of the scale of contribution to the subject matter of these reports by the various sources of intelligence already mentioned will be found in Appendix I to this report. A diagram prepared by Hauptmann ZETZSCHE summarising the sources which went to make up Ic's publications appears in Appendix II. (a) Maps showing Order of Battle. Maps of the Western Front (Great Britain and France), Southern Front (Italy), Mediterranean area and the world as a whole were issued monthly down to Divisional level and to O.K.W., O.K.L., O.K.H. and O.K.M. Printing difficulties were responsible for this limiting of distribution. (b) Rechenzettel (Allied Strength Estimate). Issued monthly down to Divisional level and to the Flugmeldedienst. (c) Truppenfeststellungen. Covered unit transfers, rearmament and changes of subordination and command, quoting the source of each item, e.g. Presse, Grönbild (covername for Listening Service). (Issued every two to three days to Luftflotte Ic's and the Flugmeldedienst). (d) Appreciations of the Air Situation. Teleprinted at three to five-daily intervals to specialist departments of O.K.W, O.K.H., O.K.M., Luftflotte Ic's and Air Observation Units, these appreciations covered tactics employed against special targets, new operational procedures, estimates of Allied production and losses, ferrying figures, invasion potentialities. (e) Red Books. Issued by Gruppe B of Fremde Luftwaffen West, the so-called Red Books contained data concerning Allied targets and airfields and those of neutral countries. (f) Target Data and Photographs. Also issued by Gruppe B. (g) Notes on Allied Air Armament. Figures of Allied production and losses, derived mainly from press and radio reports were prepared for O.K.L. headquarters units. German and agent reports of aircraft shot down were disregarded owing to unreliability. These figures, as well as Ic predictions, proved more accurate than those issued by TLR/Rü. (h) Reports on Allied Morale. Contained notes on morale, supplies, political questions, economy, etc. derived from P/W statements and extracts from captured letters. (i) Foreign Comment on the Air War. Press and radio opinion concerning the German and Allied air forces, presented in tendencious form to illustrate various themes, such as, for instance, that the G.A.F. was handmaiden of the German Army. (j) Ic Kurzmeldungen. Immediate reports on new aircraft types, new operational procedures, new commanders and their characteristics, new weapons and apparatus, etc. Distribution was extremely varied to include all possible interest parties. Up to the middle of 1944 advance warnings of Allied attacks, derived from P/W interrogations, captured maps and target data, were also promulgated in this form. After that date, to avoid unnecessary delay, they were issued independently at source by Auswertestelle West. (k) Stichworte zum Feindeinsatz (Notes on Enemy Operations). Contained extracts from P/W interrogation reports of special interest, evaluations of captured documents, press and radio reports etc. Cartoons from the foreign press added immensely to its popularity. It was issued every three to five days and distributed to some 60 departments (O.K.L., Commands, Flugmeldedienst Units, Research, Industry, etc.). (l) P/W Interrogation Reports. Demand for these was great largely owing to the political observations they contained, and until about August 1944 they were allowed a wide distribution. After this data the original reports were limited to Commands sod Air Observation Units, the remainder receiving "Stichworte sum Feindeinsatz" instead. (m) Blue Books. Instituted by KIENITZ at the end of 1943, the Blue Books dealt with subjects of a confidential nature, e.g. American day operations, A1lied ground support, British navigation, etc. However, in spite of a wealth of illustration and good printing they proved a failure, being too bulky to be easily read, apart from the contention in certain high quarters that they only amounted to Allied propaganda. (n) Einzelnachrichten des Ic Dienstes (Special Ic Studies). The first of this series was brought out in the middle of 1943, nothing of the kind having been attempted before. At first they appeared weekly on such subjects as "American day and British night operations", "Experiences of Fliegerkorps IX in the bombing of London", etc. With the dropping of the Blue Book series round about June 1944, E-N began to include such restricted subjects as "Allied twin-engined operations', "American fighter navigation", etc. Difficulties were encountered in its distribution, which were countered by the printing of 3,000 copies. It was highly valued by such as managed to get hold of it, and was in constant demand by the Wehrmacht, industry and research. (o) Schnellbildsendungen (Rapid Photo Delivery). This was a system, inaugurated by Ic/See, of delivering negatives to Commands in order that the latter might run off as many prints as were required by subordinate units. The system was originally utilised by Ic/See for distributing Ship types, but Ic applied the idea generally to the swift distribution of new aircraft types, captured H2X negatives, and apparatus, aerial photographs of airfields, etc. The system did not work effectively; for instance, it took longer to procure both positives and negatives from the Main Photographic Section than to obtain the required number of prints. Moreover, the shortage of photographic material at Commands made it difficult for them to do the necessary printing from the negatives which they received. Finally, the previous system of delivering normal prints had to be reverted to. A.D.I.(K) and Walter A. Frank U.S. Air Interrogation. for:- S.D. Felkin 2nd October 1945 Group Captain. SECRET. APPENDIX I. AN ASSESSEMENT BY HAUPTMANN ZETSCHE OF THE RELATIVE CONTRIBUTIONS OF IC SOURCES TOWARDS FINAL APPRECIATIONS BY CHEF IC. A. ORDER OF BATTLE. W/T Listening Service……………………………………… 70% P/W Statements ) Captured Material )…………………………………………… 20% Press ……………………………………………………………………………… 1% Air Photos ………………………………………………………………… 9% B. SUBORDINATIONS AND CHAINS OF COMMAND. W/T Listening Service……………………………………… 50% P/W Statements ) Captured Material )………………………………………… 5% Press ……………………………………………………………………………… 45% C. PERSONALITIES. Press ……………………………………………………………………………… 90% P/W Statements ) Captured Material )…………………………………………… 10% D. OPS. APPRECIATIONS. P/W Statements ……………………………………………………… 55% Captured Material ……………………………………………… 20% W/T Listening Service …………………………………… 20% Press ……………………………………………………………………………… 5% E. TECHNICAL APPRECIATIONS. P/W Statements ……………………………………………………… 30% Captured Equipment …………………………………………… 50% Press ……………………………………………………………………………… 20% F. ESTIMATES OF ENEMY PRODUCTION. Ferrying and O.B. Data (Mainly W/T Listening Service) …………………………………………… 35% Enemy Losses …………………………………………………………… 30% Radio and Press …………………………………………………… 30% P/W Statements ……………………………………………………… 4% Agents' Reports …………………………………………………… 1% G. ESTIMATES OF ENEMY LOSSES. P/W Statements ……………………………………………………… 20% Press and Radio …………………………………………………… 40% W/T Listening Service ………………………………… 30% Neutral Reports …………………………………………………… 9% Agents' Reports …………………………………………………… 1%" |
Radio and radar equipment in the luftwaffe
"A. D. I. (K) Report No. 365/1945
THE FOLLOWING INFORMATION HAS BEEN OBTAINED FROM P/W AS THE STATEMENTS HAVE NOT AS YET BEEN VERIFIED, NO MENTION OF THEM SHOULD BE MADE IN INTELLIGENCE SUMMARIES OF COMMANDS OR LOWER FORMATIONS, NOR SHOULD THEY BE ACCEPTED UNTIL COMMENTED ON AIR MINISTRY INTELLIGENCE SUMMARIES OR SPECIAL COMMUNICATIONS. RADIO AND RADAR EQUIPMENT IN THE LUFTWAFFE – V. I.F.F. 1. This report is the fifth of the series dealing with radio and radar equipment in the Luftwaffe. As in the case of the previous four reports (A.D.I.(K) 343, 357, 362 and 363/1945), it is based on interrogation of General Nachrichtenführer MARTINI, Director General of G.A.F. Signals, and some members of his staff, and has been supported by a number of relevant documents of recent date which were in the possession of the General's Chief of Staff. 2. For convenience in reading, the report is divided into three main sections covering the following applications of I.F.F. A - Flak. B - Early Warning Radar. C - Air-to-Air Recognition. GERMAN VIEWS ON THE IMPORTANCE OF I.F.F. 3. Before the outbreak of war the practical application of radar was mainly concentrated upon its use as an aid to Flak, and the Germans did not realise the importance of an early warning service until after hostilities had begun. In consequence the need for the identification of friendly aircraft picked up by radar sets arose initially mainly in conjunction with Flak requirements. 4. Owing possibly to the fact that the first solution to the Flak problem was not as successful as that achieved in connection with early-warning radar, while at the time great importance was attached to Flak as a defensive weapon, much effort was devoted in the first few years to producing a suitable identification system for that arm. 5. By 1944, the American bomber force was able to bomb Berlin by daylight in clear weather with insignificant losses by Flak, despite the application of various radar and optical aids. As a result, Flak had fallen into disrepute as to defensive weapon. 6. This opinion of the ineffectiveness of Flak was very pronounced among the members of the Signals Staff of the G.A.F. and it is hoped to give their reasons for this view in a later report in this series on Ground Radar. Flak was regarded by them as an out of date weapon and for this reason as well as on account of the inherent difficulties of the problem, practically no effort was made to provide a means of identification of friendly aircraft for Flak purposes during the later stages of the war. 7. On the other hand the position of early warning radar was exactly the reverse and as early warning became vital so the G.A.F. attached ever greater importance to I.F.F. for early Warning radars, particularly in connection with bad weather and night raids involving feints and spoof sorties. It was considered essential to obtain a clear picture of the tracks of Allied raiding aircraft and to avoid any confusion with German fighter aircraft which also flew in group. The latest endeavour in this field went so far as to provide separate identification for different G.A.F. night fighter units in order to assist ground control still further. 8. Increasing attention was also being paid to air-to-air recognition between German aircraft but this, though considered desirable, was not thought to be nearly so important as the essential requirement that friendly aircraft should be recognisable to the early warning service In order that a true picture of the progress of Allied bomber attacks could be obtained and fighter aircraft vectored to the attack by ground control. A – I.F.F. FOR FLAK 9. At the beginning of 1939 it was intended to equip all Flak sites with a radar fire control apparatus then being developed by the firm of Lorenz. The Lorenz apparatus proved unsatisfactory and in the course of 1939 the Würzburg, produced by Telefunken, was adopted for Flak fire control. 10. The need for the recognition of friendly aircraft for Flak purposes had been apparent to the Germans and an I.F.F. set for use with the Würzburg was produced, and was available at the outbreak of war. It was known as the Zwilling and was given the designation FuGe 25. 11. The 50 cm. Würzburg transmission received by the FuGe 25 caused the FuGe 25 transmitter to broadcast an audible morse signal on the same frequency, which could then be heard by the Würzburg operator in his headphones. As this was not a retransmission of the Würzburg radar pulses, it gave no indication of range and might equally well have originated from an aircraft in the vicinity beamed by some other Würzburg. General MARTINI was fully aware at this stage that the FuGe 25 was no real solution to the identification problem. 12. Meanwhile, the firm of Gema had produced the Freya for the Navy, and in October 1939 eight of these had been taken over by the G.A.F. and were stationed on the East end North Frisian Islands, where they proved their value la combatting early British bombing attacks directed against the North Sea ports. 13. In November 1939 Gema demonstrated an I.F.F. set for use with Freya which proved to be forerunner of the FuGe 25A Erstling. General MARTINI recognised immediately that this Freya I.F.F. which operated on the principle of returning the Freya pulses and which provided range measurement, was a far superior solution and he endeavoured to use his authority to have the new principle universally adopted for Flak. 14. At that time many different departments were involved and partly on this account and partly because FuGe 25 Zwilling was sponsored by the Technisches Amt, MARTINI failed to gain his point. (see also A.D.I.(K) 334/1945),paras. 95-96). It was only with great difficulty that he was able to persuade the R.L.M. in early 1940 that an order for 3,000 FuGe 25A for Freyas should be placed and even then considerable delay occurred before they were supplied. 15. During 1940 and 1941 the shortcomings of the Zwilling gradually became apparent, particularly in connection with night fighter operations, but by the time the advantages of the FuGe 25A Erstling had been recognised and the set had been finally adopted, over 10,000 Zwilling sets had already been manufactured. 16. The original Freya used a wavelength of 2.40 metres to which the FuGe 25A Erstling responded on 1.90 metres. To permit of the universal application of the FuGe 25A a small transmitter called the Kuh had to be built into other types of early warning radar in order to interrogate the airborne set. The response was picked up by the Gemse receiver unit. In this manner a simple pair of wavelengths were, in effect, set aside for aircraft I.F.F. purposes. 17. In spite of these achievements the Flak problem had not been completely solved, as it was not possible to produce a sufficiently beamed transmission on 2.40 metres to be certain that a response seen on the recognition tube was that of the aircraft in the Würzburg beam. Various expedients were tried out but as mentioned above, the problem still remained unsolved up to the end of the war and was finally abandoned. FUGE 25 - ZWILLING. 18. The FuGe 25 Zwilling (= twin) received the Würzburg pulses on a 50 cm. carrier wave and re-transmitted a morse recognition signal on the same frequency, but as it did not re-transmit the pulses received, no range could be obtained by the ground set. The shortcomings of this system were recognised in 1941 end a series of attempts was made to overcome them by using responder technique as detailed below. HÄUPTLING. 19. In order that the Flak Würzburgs should get a range with their recognition signal, the FuGe 25 Zwilling was converted so that the pulses received on 50 cm. were re-transmitted on the FuGe 25a wavelength of 1.90 m. This conversion was complete by the autumn of 1942. The new set was called Häuptling. About this time, however, Allied jamming of Würzburgs commenced and the Germans were forced to produce Würzburgs on various wavelengths known as Insel A 53.0-54.2 cm. and Insel B 56.7-58.0 cm. As a result, the FuGe 25 no longer responded to all Würzburgs and so the Häuptling did not fulfil its task. KUCKUCK. 20. When Würzburgs on various frequencies were introduced, the basic FuGe 25 set was finally given up and the FuGe 25A Erstling became the standard airborne set. 21. All Würzburg radars were provided with a Kuh type transmitter on 2.40 m. called the Kuckuck, the aerials for which were placed in the Würzburg paraboloid. The resultant polar diagram was extremely wide-angled as compared with the Würzburg beam and a response at the same range as that of the aircraft held in the beam was not positive proof of identity if many aircraft were about. 22. In addition the 2.40 metre transmission spilled over and could be picked up at distances of as much as 10/15 km. behind the Würzburg set, so that even aircraft behind the Würzburg were triggered off. As Flak was only interested in aircraft within firing range of the Würzburg, this procedure was at its weakest with the very type of recognition for which it had been expressly designed, and in consequence Kuckuck was finally condemned as a failure in 1943. WOBBELBIENE. 23. With the failure of Kuckuck the Germans decided that the only solution to the Flak problem was to apply British I.F.F. technic. The FuGe 225, known as Wobbelbiene, which was designed to sweep through (Wobbeln) the 50 cm. to 60 cm. band and act as responder (Biene), was developed for this purpose and was to have been introduced in the winter of 1943/1944. This, however, still did not cover the new Würzburg Insel C of 62.3 - 63.8 cm., which was being introduced in 1944. 24. Further modifications to Wobbelbiene were considered in order to cover this waveband but many difficulties, both mechanical and electrical, had been encountered with the design despite the fact that the set was said to be a direct copy of British R.F.3090. 25. The project was ultimately given up before being used operationally and up to the end of the war no satisfactory solution to the Flak problem had been found. B - I.F.F. FOR EARLY-WARNING RADAR. 26. The Kuh and Gemse arrangement in conjunction with the FuGe 25A whereby two wavelengths, 2.40 m. for interrogation and 1.90 for response, had been set aside for I.F.F., worked satisfactorily for early-warning radars. MARTINI's staff considered that this system was superior to the then current British principle of an I.F.F. set sweeping through the various early-warning wave bands and responding only intermittently to a particular frequency. 27. When Allied jamming became serious, it was fully realised that the use of one special wavelength for recognition purposes, rendered recognition very vulnerable to Allied countermeasures although it was considered difficult from a technical point of view to carry out effective jamming. 28. To anticipate this eventuality, a tactical requirement was formulated in 1943/1944 calling for a FuGe 25A working on a new frequency and the Erstling-Grün was designed and manufactured, but never put into use as the Allies did not employ the expected counter-measures. 29. With the advent, during the course of 1944, of automatic sweeping ground radar with a P.P.I. presentation like Jagdschloss, a new problem for I.F.F. arose. So long as the recognition signal emitted by the aircraft in responding was a morse letter there was no guarantee that it would come up effectively as the beam swept over the target aircraft. 30. The Germans' first solution of this problem, was the Erstling-Rot, a form of FuGe 25A, which responded with the morse identifications separated by a six-second dash, thereby ensuring that response was sufficiently continuous for the ground set to sweep the aircraft at least once whilst the airborne set was transmitting the long dash. 31. In 1944 Allied radio countermeasures became more intense and it was realised by the Germans that the general principle applied in all their anti-jamming countermeasures must also hold for I.F.F. This principle was to have a number of alternative frequencies available for every type of set and a new tactical requirement embodying this facility was, therefore, formulated. 32. It was decided that the new I.F.F. set must also give continuous presentation of the recognition response so that ground controllers could immediately identify friendly aircraft. At the same time this would solve the identification problem for panoramic ground equipment of the Jagdschloss type. 33. This requirement led to the development of the Neuling which, however, had not been used operationally up to the end of the war. It appears to have been a set with a number of novel features which are discussed below at some length. 34. In complete contradiction of the principles used in all earlier sets, the problem of I.F.F. for centimetre radar was to be solved by using the searching beam to trigger off the I.F.F. set. A small unit called the Frischling was to convert the centimetre wavelength to a frequency which would be accepted by the standard Erstling receiver. FuGe 25A – ERSTLING. 35. The FuGe 25A is the well known set which has been installed in every German aircraft since about the beginning of 1942 and which had also been used for Egon control(see A.D.I.(K) 357/1945). It was often referred to as the Erstling. 36. It was a responding transmitter receiving on 2.40 m.(the original Freya frequency) and re-transmitting the pulses received on 1.90 metre. A morse signal repeated roughly every two seconds was superimposed on the re-transmission, six alternative codes being available. It was claimed that an advantage of using a morse letter as recognition was that it could easily be read by ear through the operator's headphones and that this was easier than following the recognition C.R. tube by eye. ERSTLING-ROT. 37. In the early part of 1945 the G.A.F. began to introduce a form of FuGe 25A known as the Erstling-Rot. It was designed to deal with recognition difficulties occurring with ground radar of the automatic sweeping type such as Jagdschloss. 38. The Erstling-Rot separated the morse signals by a dash of six seconds duration - a period sufficient to ensure that the ground radar swept the target. It embodied an improvement in that it permitted of 18 different morse recognition signals being superimposed on the re-transmission instead of only six as in the case of the original Erstling. 39. Originally it was to have a more powerful transmitter but this requirement was allowed to lapse when it was realised that the factors limiting range were the sensitivity of the FuGe 25A receiver or the power of the ground interrogator. A project for a more powerful ground interrogator called the Gross Kuh was considered, but as the ranges obtained with the normal Kuh were thought to be adequate this idea was abandoned. ERSTLING GRÜN 40. The G.A.F. signals staff realised that the use of a single frequency for recognition purposes exposed them to the danger of Allied R.C.M. In view of this a version of the FuGe 25A operating on a new frequency was produced which was known as the Erstling-Grün. The wavelengths used were to be 2.52 metres for interrogation and about 2.00 metres for the response. 41. The small shift in wavelength was dictated by the need to avoid new ground equipment. With the relatively small frequency change the Kuh and Gemse were capable of being adjusted to the new frequencies by the field "S. und I" (maintenance and repair) teams, and so an economy was effected. 42. Erstling-Grün was never used operationally as Allied jamming of the original Erstling frequency was never experienced. NEULING. 43. The FuGe 226, usually referred to as the Neuling, was to have been available for installation in operational aircraft by December 1944, but owing to difficulties encountered during the trials carried out at Rechlin it was not yet ready at the time of the capitulation. Lorenz were responsible for its production and Dr. KRAMAR of that firm was considered the expert on its technical aspects. 44. The Neuling, which was considered to be a good solution to the identification problem, was designed to overcome previous difficulties and to provide new facilities. The tactical requirement originally called for were:- (a) Continuous presentation of I.F.F. signals on all types of early-warning radar including panoramic radars such as Jagdschloss. (b) Twelve alternative pairs of frequencies for I.F.F. (later reduced to six pairs) - each pair to consist of an interrogating and response frequency. (c) Air to air recognition between German aircraft. 45. This ambitious programme was not fulfilled when the FuGe 226 was tried out in the later part of 1944 at Rechlin, but the experts who carried out the trials believed that the main requirements could be met by sacrificing half the pairs of frequencies, thereby limiting the set to six frequency pairs. 46. To meet requirement (a) and provide continuous presentation of the recognition signal on the ground radar, and at the same time permit the simultaneous use of a number of different frequencies, the responder and transmitter were to sweep very rapidly through the selected band which was believed to be 125 - 167 mc/s. 47. The receiver and transmitter sweeps were synchronised a few megacycles apart, so that the response was always on a slightly different frequency to that of the interrogation. This sweep was to be carried out sufficiently rapidly for the blip on the recognition tube of a ground set interrogating on one of the frequencies to appear continuous to the eye of the operator. 48. Presumably, even allowing for after-glow effects, the frequency of sweep must have been extremely high. It was not known exactly what repetition rate was used, nor what technical method was employed to obtain such a high rate of sweep through the band. 49. Great importance was attached to requirement (a) as it allowed ground controllers to obtain continuous recognition on Jagdschloss type P.P.I. tubes and so distinguish between friendlies and hostiles. It also greatly assisted the control of friendly fighters by Freya stations. 50. The requirement (a) for continuous presentation of the recognition signal appeared to have precedence over the requirement (b) for twelve alternative pairs of frequencies since in order to meet (a) Rechlin decided that the number of channels available would have to be cut from twelve to six pairs. It was found by Rechlin that squeezing twelve separate frequencies for response (which could not overlap with interrogation frequencies) into the swept band caused the band width of the individual responder frequencies to be so narrow that the recognition blip became too thin and indistinct on the ground radar recognition tube. 51. It was hoped that requirement (b) - the provision of alternative frequencies - would prove a safeguard against possible Allied R.C.M. It was also believed that it would aid in mitigating clutter on the recognition tubes of Freya etc., since interrogation would be spread over a number of frequencies. Wandering blips resulting from neighbouring ground radars which triggered off other aircraft obscured the tube and caused this clutter. 52. Efforts had also been made to overcome this trouble by building an arrangement into ground radars which prevented interrogation being carried out continuously as was often the undesirable habit of operators. By means of this arrangement power was cut off from the Kuh aerials about a minute after the interrogation switch had been depressed and this device also prevented interrogation until a further short period had elapsed. 53. Requirement (c) was only third in importance. The air to air I.P.F. facility, however, entailed a disadvantage which was regarded as a serious one, namely that when being used for that purpose the Neuling was no longer capable of responding to interrogating by other radar apparatus on the ground. 54. The tactical application of the Neuling must be considered in relation to the defence problems which the Allied bomber forces set Germany in 1944. The Germans regarded it as essential for the defence and more particularly for night defence that they should be able to obtain an absolutely clear picture of the air situation and identify Allied bomber streams unequivocally and at a glance. The P.P.I. presentation of ground radar like Jagdschloss and Forsthaus was beginning to be appreciated and attempts were being made to control directly from these panoramic displays. 55. It will be remembered too that German night fighter Gruppen operating under the Verbandsflug system flew together in loose groups or patrolled in the area of a selected beacon. It was, therefor, considered essential that these aircraft should be immediately identified as friendly on the P.P.I. tube and not confused with a bomber stream. It was also held to be of great value to ground controllers to have a means available for identifying one Gruppe from another with equal immediacy. 56. To attain these requirement one of the six interrogating frequencies available was allotted to early-warning radar and the remaining five were to be given to different night fighter Gruppen or Geschwader. The Neuling in each aircraft was then so switched that it could receive and respond to two of the six Neuling frequency pairs, viz. the early-warning frequency and the frequency allotted to the Gruppe to which the aircraft belonged. 57. For Jagdschloss panoramic ground equipment a complete continuous identification picture divided into friendlies and hostiles could be obtained by interrogating on the earlywarning frequency. 58. By simply training a knob the transmitter and receiver could be switched to the frequency pair of a particular operational Gruppe and this presented no technical difficulty with Breitband aerials. Aircraft of that Gruppe could then be identified immediately in the over-all picture on the P.P.I. tube. This facility was considered a great advance both from the point of view of I.F.F. and of ease of ground control of night fighters. 59. P/W who claimed to have seen a ground P.P.I. display during the Neuling trials stated that the recognition blip came up on the tube as an extension of the reflected blip at slightly greater range and that it subtended a greater angle in the display. He described it as a "sausage rather longer than the aircraft blip and sitting on it". 60. Reference has been found in a document to a Neuling covering the band 1,000-1,500 mc/s. The P/W who was responsible for the formulation of radar requirements stated that he had never heard of a Neuling on this frequency, but suggested that it might be for use in responding directly to the beam of 25 cm. ground radars such as Forsthaus F. This suggestion appears unlikely, however, as it seems to involve a departure from the Neuling principle. FRISCHLING. 61. In view of the introduction of highly beamed 9 cm. ground radar such as Forsthaus Z and Jagdschloss Z, it had been decided to depart from the principle of using a separate interrogation frequency and to employ the search beam to trigger off I.F.F. For this purpose a special attachment to the airborne Erstling called Frischling had been planned. This was a receiver on 9 cm. which converted the frequency to that of the Erstling so that it responded on 1.90 metres. 62. With the planned introduction of the Neuling, consideration was given to a modification of the Neuling whereby a Frischling attachment would be built in for the purpose of converting the frequency and so trigger off the Neuling in the same manner. P/W was not clear whether this would only apply to one frequency of the Neuling, nor did he know what technical method would be used to accomplish it. 63. Frischling was to be produced by Telefunken but was still in course of development when the ear came to an end. AIR-TO-AIR I.F.F. 64. For some reason as yet unexplained, the German interest in air-to-air recognition only became great enough for suitable equipment to be designed during the last stages of the war. During the year preceding the termination of hostilities, captured night fighter crews consistently maintained that some improved form of I.F.F. which would allow recognition of friendly aircraft was expected but no attempt appears to have been made to adapt the FuGe 25A for this purpose. 65. The present P/W assert that so long as I.F.F. and airto- air search operated on metric wavelengths and could not be sharply beamed, the problem of air-to-air recognition could only be half solved, as a range identification only was obtained. It was realised that with a dense bomber stream there would be so many aircraft comparatively near to the fighter that recognition by range only was not very valuable. Nevertheless the Neuling FuGe 226, which was shortly to be introduced, was to have provided air-to-air I.F.F. facilities. 66. In the beginning of 1945 the Germans tackled this problem for centimetric search gear and proposed to depart from their original principle of separating search and I.F.F. interrogation. The search beam of centimetre equipment was to be received by the Frischling attachment to the airborne I.F.F. set and the centimetre frequency so converted that the I.F.F. net was triggered off. NEULING. 67. In the Neuling, which has been described above in detail, it was planned to provide air-to-air I.F.F. facilities by the use of a special switch which, when depressed, reversed the roles of the receiver and responding transmitter. The interrogating aircraft could then trigger off the I.F.F. set of neighbouring aircraft and receive its response on the receiver portion of the Neuling. 68. The response was to be fed through to the SN 2 or other set in use and the presentation of this recognition signal was to take the same form as in the Freya, i.e. a second time base carrying the I.F.F. signal was to appear to one side of the main time base. 69. During this operation no I.F.F. response could be made to interrogating ground stations, and this caused some apprehension. To discourage excessive use of air-to-air interrogation, the switch in the aircraft was to be awkwardly placed and inconvenient to operate – a typically German solution to a problem of aircrew training. FRISCHLING. 70. The night fighter search apparatus – the Berlin N.1.A. and the Bremen 0 on 9 cm, and later probably the München on 3 cm were to go into service some time in 1945 as will be discussed in a future report in this series. 71. To provide air-to-air I.F.F. facilities the Frischling, mentioned in paras. 61-63 above, was to be attached to the FuGe 25A and later built into the Neuling as a modification. It was to convert the centimetric beam transmission of air-to-air search apparatus to the frequency of the Erstling FuGe 25A so that the latter was triggered off directly by the searching beam. FALTER WITH GÄNSEBRUST. 72. As early as 1940, experiments had been made with infrared homing on to aircraft exhausts using an infra-red telescope of the Bildwandler type called Spanner. This met with only limited success on account of restricted range and the dependency of infrared on clear weather conditions but the idea was never completely dropped. 73. With the introduction of night fighter commentary and the Verbandsflug tactics in 1944, it was required that night fighter units should fly in groups and keep as close together as possible. 74. It was, therefore, proposed to introduce an aid in the shape of some form of infra-red navigation lights to be viewed through an infra-red telescope. The latter, which was a form of Spanner, was named Falter. As, however, the field of view of this telescope was confined to about 15° it soon transpired during trials at Werneuchen that it was not a practical proposition. 75. In 1944 the idea of using infra-red for recognition which had long lain dormant was once more evoked by the discovery that British bombers were carrying en infra-red recognition light. It was, therefore, proposed that German night fighters should home on to the infra-red lights by means of the Falter. 76. For mutual recognition between night fighters an infrared lamp termed "Gänsebrust" was also planned. It was hoped that Gänsebrust might not only allow recognition between German aircraft but possibly afford some protection from British night fighters which might become uncertain in their recognition of a German night fighter if the Gänsebrust was flashed intermittently even though the British code in use for the night were not known. A.D.I.(K)and S.D. Felkin U.S. Air Interrogation. Group Captain 2nd August 1945" |
THE BERLIN GERÄT
"SECRET A. D. I. (K) Report No. 188/1945
THE FOLLOWING INFORMATION HAS BEEN OBTAINED FROM P/W AS THE STATEMENTS HAVE NOT AS YET BEEN VERIFIED, NO MENTION OF THEM SHOULD BE MADE IN INTELLIGENCE SUMMARIES OF COMMANDS OR LOWER FORMATIONS, NOR SHOULD THEY BE ACCEPTED UNTIL COMMENTED ON AIR MINISTRY INTELLIGENCE SUMMARIES OR SPECIAL COMMUNICATIONS. THE BERLIN GERÄT. 1. A recent German Army prisoner, a doctor of Physics of Vienna University, had worked for fifteen months up to 23rd October 1944 in the High frequency research laboratory of the G.E.M.A. G.m.b.H. at Berlin and latterly at Wahlstatt, near Liegnitz. During that period one of his tasks had been to determine the characteristics of the transmission lobe from the aerials of the Berlin Gerät. 2. The Berlin Gerät is a German development of the British H2S, on a wavelength of 9.1 cm., but employs a totally different aerial system developed by Siemens. Whilst P/W's description of the apparatus given in the following paragraphs, is considered to be reliable, he had no knowledge of its eventual operational use. 3. Acknowledgements are due to A.D.I.(Science) for their collaboration in the interrogation. AERIAL SYSTEM 4. The sketch in the Appendix to this report gives an impression of the Berlin aerial unit. 5. The four rods forming the aerial array are composed of a plastic called Trollitul and are of circular cross-section about 4 to 5 cm. in diameter at their base, tapering somewhat to a rounded end. The rods lie parallel to the plane of a circular metal plate of about 1 metre diameter, and about 15 cm, clear of it. 6. The energy to be radiated is led to the aerial rods by a concentric feeder which forks into too branches where it enters the metal plate and again fork; making 4 branches to feed the four aerials. At each of the forks the concentric feeder widens into a funnel shape called a transformer piece, the sloping side of which is a half wavelength long, that is, 4,5 cm. 7. A Trollitul dome some 40 cm in depth covers the aerial array and fits, flush to the edge of the circular metal plate. 8. The whole unit including the aerials can be made to rotate. This prisoner had never seen the apparatus fitted either to an aircraft or a ship and he did not know the speed of rotation; he has an idea however, that the axis of rotation was at an angle to the geometrical axis of the cylindrical disc, so that in an aircraft the transmission beam would be thrown slightly downwards or in a ship, upwards. TRANSMISSION LOBE 9. The Berlin Gerät has a half-value lobe 10° in width in the plane of the four aerial rods and 35° to 37° in width at right-angles to the plane. The lobe was measured by the normal method; the aerial unit, however, was not resting on a metal surface as it would have done if built into an aircraft. Under these conditions the lobe was symmetrical about the axis of the Aerial array. P/W presumed that if the aerial system were built under the fuselage of an aircraft shadow effects would cause the lobe to be asymmetrical or to be deflected. 10. The experiments which P/W had conducted were in the open air; he had found that when rain covered the Trollitul dome with a layer of moisture, no transmissions could be detected, even at a range of 20 metres, along the line of the axis of the aerial rods. He thought that in these circumstances the whole lobe was strongly deflected. PRESENTATION. 11. This P/W had read the regular reports of the "Rotterdam Sitzungen" - a special committee on centimetre radar - and one of these reports contained a description of the Berlin presentation, including photographs taken in an aircraft flying over Kiel Bay. 12. From this report he could remember that the presentation was on a circular screen; coast-lines of the mainland and of islands showed as white ribbon-like stripes and towns appeared as white areas, whilst individual ships in Kiel bay could be seen as small elongated white blobs. 13. He had the impression that distant towns, although slightly distorted in the picture, still retained their approximate shape. He thought that in the photographs of the presentation an area of about 60 km. in diameter was represented; he did not know, however, at what height the aircraft had flown. RECEIVER MAGNETRON. 14. It was stated by P/W that a weak point of the Berlin apparatus was the receiver valve, which frequently broke down. This valve was a magnetron contained in a glass envelope, with a solid metal anode in which four or six holes had been drilled. An impression of the valve, which P/W believed was called the MD2, appears in the sketch in Appendix I. USES OF BERLIN GERÄT. 15. Apart from its use in giving a panorama of the ground over which an aircraft was flying, P/W knew of no other air uses of the apparatus. He understood, however, that the device was to be installed in U-boats as an aircraft warning device. A.D.I.(K) and U.S. Air Interrogation. S.D. FELKIN 24 February 1945. Wing Commander" |
LUFTWAFFE ELECTRIC ALTIMETERS
"SECRET A. D. I. (K) Report No. 362/1945
THE FOLLOWING INFORMATION HAS BEEN OBTAINED FROM P/W AS THE STATEMENTS HAVE NOT AS YET BEEN VERIFIED, NO MENTION OF THEM SHOULD BE MADE IN INTELLIGENCE SUMMARIES OF COMMANDS OR LOWER FORMATIONS, NOR SHOULD THEY BE ACCEPTED UNTIL COMMENTED ON AIR MINISTRY INTELLIGENCE SUMMARIES OR SPECIAL COMMUNICATIONS. RADIO AND RADAR EQUIPMENT IN THE LUFTWAFFE – III. ELECTRIC ALTIMETERS 1. This report in the third of the series dealing with radio and radar equipment in the Luftwaffe. As in the case of the previous two reports (A.D.I.(K) 343 and 357/1945), it is based on interrogation of General Nachrichtenführer MARTINI, Director General of G.A.F. Signals, and a few important members of his staff, and has been supported by a number of relevant documents of recent date which were in the possession of the General’s Chief of Staff. 2. The development of electric altimeters was probably the only field of G.A.F. airborne radar technique in which the Germans approached Allied standards. The FuGe 101 had long been standard equipment and was an entirely satisfactory instrument apart from the fact that height readings were limited to a maximum of 750 meters. 3. Efforts were being made to produce improved and, in particular, more compact electric altimeters which would give readings up to great heights, and it was hoped that the FuGe 104, described below, would meet all current requirements. FuGe 101A. 4. This standard sensitive altimeter which had a range scale of 0 – 150 meters or 0 – 750 meter, is already familiar. By the end of the war it was only built into aircraft flying by night and seems to have been used for checking heights in the approach. FuGe 102. 5. The FuGe 102 was an improved electric altimeter giving height readings ranging from 100 to 15,000 meters. It was developed at Oberpfaffenhofen in 1942. Presentation was in the form of a circular trace on a C.R. tube with the zero mark in the 12 o'clock position. 6. As the aircraft climbed, a break in the continuous trace occurred extending in a clockwise direction from the zero position, and this gave the height measurement. The end of the gap was not clear cut and in consequence accuracy was poor. The presentation unit was considered too bulky as it occupied too much space in the Ju.88 and similar twin-engined aircraft. Only a few were produced and used operationally, chiefly in the F.W.200’s and He.177’s. FuGe 103. 7. One P/W, who had made test flights at Werneuchen in the spring of 1943 with the purpose of testing the FuGe 103, which was known under the code name "Jena", considered it a most successful and reliable instrument. It was designed and developed by Zeiss for use in the He.177 and was tested under the supervision of Stabs.Ing. Dr. KNOSKE. P/W understood that it was part of the standard equipment of the series-produced Ju.188’s. 8. The indicator dial of the instrument was calibrated from 0 – 4,000 meters in a clockwise direction. Height was indicated by a fine blip about 1 cm long which appeared on the circumference of the tube, the forward blip being taken for the reading. The sharpness of the tip was such that height could be read to within 25 metres, although the tube was only calibrated to 50 metre intervals. 9. Heights over 4,000 and 8,000 metres were read on the second and third evolution of the blip, but no "hour-hand" was incorporated, so that the pilot could only distinguish between say 5,000, 9,000 or 13,000 metres by using his common sens. 10. The FuGe 103 indicator unit, although only 10 - 12 cm in diameter and about 35 cm long, was still too bulky and was never used operationally on a large scale. FuGe 104. 11. The FuGe 104 was a scaled-down model of the FuGe 103 and went by the same code name "Jena" and had an identical type of display. It was to supersede the FuGe 102 in all aircraft equipped with the latter, as its accuracy and presentation were as good as the FuGe 103 and better than the FuGe 102, and it had the advantage of being smaller than either of them. It was hoped that it could be the final type of altimeter. 12. In the Signals Equipment Emergency Program reproduced as Appendix II to A.D.I. (K) 343 and 357/1945 it will be seen that under the heading of "234, bombers" both the FuGe 102 and the FuGe 104 are shown. P/W thought that in the table there should either have been an arrow connecting these two sets to indicate that the FuGe 104 was to replace the FuGe 102, or alternatively that 102 was a misprint for FuGe 101A. A.D.I.(K)and S.D. Felkin U.S. Air Interrogation. Group Captain 27 July 1945 Distribution:- same as for report 357/1945" |
EQUIPMENT OF A Y-SITE
"SECRET A. D. I. (K) Report No. 527B/1944
THE FOLLOWING INFORMATION HAS BEEN OBTAINED FROM P/W AS THE STATEMENTS HAVE NOT AS YET BEEN VERIFIED, NO MENTION OF THEM SHOULD BE MADE IN INTELLIGENCE SUMMARIES OF COMMANDS OR LOWER FORMATIONS, NOR SHOULD THEY BE ACCEPTED UNTIL COMMENTED ON AIR MINISTRY INTELLIGENCE SUMMARIES OR SPECIAL COMMUNICATIONS. EQUIPMENT OF A Y-SITE. 1. The operational procedure in the control of fighters by the "Y" procedure was described in A.D.I.(K) 525/1944. The interrogation of the two G.A.F. signals officers, who supplied the information for that report, has produced a large amount of information on Y-site and airborne equipment which is of rather more limited interest. The present report, which contains that information, is therefore being given a limited circulation. 2. Captured documents on the "Y" procedure have helped to add further information, and have provided a further basis for interrogation; these documents have been forwarded to A.I.4.(b). TRANSMITTER HUT. 3. Four types of "Y" ground transmitter are believed to be in use. Y-Stations in Germany are said to be equipped with a four-stage transmitter known as Berta I or Berta II, with an output of 80/100 watts and a range of 400/500 kilometres, when controlling aircraft at heights of 5,000/7,000 metres. 4. Another transmitter used in Germany is the S16B (Sender 16 Boden), which is a modification of the FuGe 16, and which has a maximum range of 250 km. when used in conjunction with a Rechlin range-measuring unit, or a range of 250/350 km. when used with the more accurate Siemens range-measuring unit. 5. Y-Stations installed in France employed a Sadir 80/100 watt transmitter, usually also in conjunction with a Siemens range-measuring unit; the ranges achieved by this combination were of the order of 400/500 kilometres for aircraft operating at heights of 5,000/7,000 metres. 6. The transmitter S16B (Sketch I) is operated in the following sequence of steps:- (i) Main switch (1) first to stop Hzg (Heizung = heating) then after two minutes to stop "Ein" (on). Lamps (2) and (3) light up. (ii) Select frequency to be used. Switch (4). Frequency indicated in Window (5). (iii) Switch (6) to stop Test. (iv) Knob (7) (blip intensity) turned until vertical line appears on Cathode Ray tube (8). (v) Definition of line re-adjusted by means of Knob (9). (vi) In the meantime operator of range-measuring unit has switched on "Geber" for production of "Messton" (Modulation tone). (vii) Knob (10) turned to right until the luminous area produced in (3) corresponds to 80% modulation. (viii) Transmitter now ready tuned for transmission to commence. Switch (6) to right (Load). (ix) Transmission is automatic when the switch for the modulation note is depressed by the operator of the range-measuring unit; or for R/T instruction when key for R/T circuit is depressed by the plotter. 7. When taking over a "Y" controlled aircraft from one station to the next, the following procedure for tuning the receiver and transmitter is carried out by the station taking over when using a S16B transmitter. 8. As a first step the receiver of the range-measuring unit is set to the transmitter frequency given for the aircraft. The range measurer then tunes his receiver to maximum audible strength of the modulation tone received ("Hörmaximum"). 9. The 80% modulation image on Cathode ray tube (8) then shows an additional bright vertical line within the area of the image. By turning frequency stop (4) this vertical line is displaced to the right. 10. The operator of the transmitter turns the frequency stop (4) until the line reaches a limiting position, and on further movement of stop (4) tends to re-trace its path to move again to the left. This turning point ("Umkehrpunkt") corresponds to the accurate setting of frequency stop (4), and provides a visual method of tuning the transmitter accurately to the receiver frequency of the "Y" aircraft. D/F'ING CABIN. 11. The D/F'ing cabin consists of an octagonal wooden hut erected on the platform of the receiver pylon; the latter are of wooden construction and according to P/W, are either 15 m. or 25 m. heigh, depending on the location of the site. 12. The present P/W were acquainted with two types of D/F equipment, known respectively as "Heinrich I" and "Heinrich III". The latter equipment is of recent origin, and was only introduced to Y-Stations in France early in 1944. "Heinrich I" D/F Equipment. 13. The aerial array of this equipment, illustrated in Sketch II, consists of four quarter-wave vertical dipoles arranged in pairs at the corners of one side of a horizontal frame about four metres long. In each pair one dipole is mounted above and one below the frame. Two half-wave reflectors are mounted on the opposite corners of the frame. A single quarter-wave dipole is mounted centrally, and is connected to the rangemeasuring unit situated at the base of the receiver pylon. 14. The vertical axis of the aerial system can be rotated about the control axis of the pylon by means of a hand-wheeled drive operated from the interior of the cabin. The vertical axis of the aerial is geared to a graduated disc, marked from 0° to 360° in a box placed centrally on the table of the D/F cabin. Readings are made through a small window carrying a hair line at the back. 15. To the left of the central box is a receiver E16P; this is the normal receiver unit of the FuGe.16, from which the A.V.C. (Regler) has been removed. To the right of the box is a voltmeter. 16. The D/F operator, who is equipped with headphones, sits in front of the box. The modulated note or "Messton" reaching the receiver is audible in these headphones, and having established the minimum position, the operator checks the direction as follows. 17. The aerial is turned out of the minimum position by about 30°, and the reading of the output meter is noted. If, on pressing a switch attached to the output meter, the voltage falls, the direction in which the bearing has been taken is correct. If, on pressing the button the voltage increases, this indicates that the aerial has to be swung by 180° to get the correct direction. 18. The readings should on the average be correct to within 0.5°, and for distances of under 100 km. to within 0.3°. This reading is spoken aloud by the D/F operator, and is recorded by a logbook-keeper (Betriebsbuchführer), who also repeats the reading on a telephone connected to the range-measuring unit and from there to the plotting room. "Heinrich III" D/F Equipment. 19. The Heinrich III, also known as the "Umtastpeiler", is referred to in documents issued by "Hochfrequenzforschung Einsatzstab Holland" as having been developed at the "Flug Funk Forschungsinstitut Oberpfaffenhofen". 20. The Heinrich III differs from the "Heinrich I" in several respects. The aerial system consists of six quarter-wave vertical dipoles, four of which are arranged in pairs at the end of a single horizontal support about 4 metres in length. The fifth dipole is mounted centrally above the D/F cabin, but also forms part of the D/F aerial system. 21. The sixth quarter-wave dipole is placed vertically within the structure of the receiver pylon midway between the D/F’ing cabin at the top and the range-measuring room at the base, and is connected to the range-measuring unit. 22. The aerial system rotates horizontally about the central axis of the pylon, and the vertical axis of the aerial is geared to the central box in the D/F’ing cabin as with the Heinrich I. 23. The D/F receiver used is the El6EP, and this operates in conjunction with an automatic device known to P/W as PUG (Peilumtastgerät), also referred to in documents an ZVG 16 P (Zielflugvorsatzgerät 16 P), and finally with a visual indicator termed AFN 2 (Probably = Anzeiger Frequenzniedrig 2). 24. The PUG is connected to E16EP as well as to a plug connection on the central box. The AFN 2 device has the appearance of a mall box, measuring approximately 20 x 10 x 10 cms., connects to the same plug. 25. The dial on the side of the AFN 2 has a pointer which is directed vertically downwards when the aerial is in the minimum position. The correct direction is now established by turning the aerial a few degrees out of the minimum position. If the pointer deflects in the same direction in which the degree graduations in the small window have moved, the bearing has been taken in the correct direction. If the pointer moves in the opposite direction to the movement of the degree graduations, then the aerial must be swung by 180°. 26. According to P/W, this device allows the D/F operator to fix the minimum position by visual means only, eliminating errors duo to the human factor when aural methods are used. Secondly, the device is automatic and does not require to be switched on each time by the D/F operator. "Heinrich II M" and "Heinrich II U" D/F Equipment. 27. Captured documents make mention of the Heinrich II M. and II U; these versions were unknown to the present P/W, but the II M is shown in a document, issued at Arnheim in May 1943 by Staaatsrat Dr. PLENDL, to utilise an aerial array with three sets of quarter-wave dipoles and reflectors. 28. The II U, mentioned in another document from the same source, and dated July 1943, is shown to be the forerunner of the Heinrich III described above, and to embody the same aerial array as the letter. RANGE MEASURING CABIN. 29. The range-measuring cabin is situated at the base of the receiver pylon, and houses a range-measuring unit. Two types of units are in use, known as Rechlin and Siemens rangemeasuring units respectively. "Rechlin" Range-Measuring Unit. 30. The "Rechlin" unit (Sketch III) was designed by Dr. BECKER of Rechlin, and constructed by a firm named Graetz. It is thus sometimes referred to as the "Becker Gestell" or the "Graetz Gestell". 31. The Rechlin, which is used principally on day fighter "Y" control stations, gives reading accurate to 1 km.; it measures the time required by the transmitted impulse to reach the aircraft and return again to the receiver of the rangemeasuring unit. This time is determined by means of an invisible point which travels along the graduations of the Cathode ray tube, and becomes visible at the moment when the returning impulse reaches the range measuring unit. 32. The tuning and operation of the Rechlin range-measuring unit are carried out ne follows:- (i) Main switch (1) to ON. Dial lamp (2): lights up. (ii) Knob (3) turned to left (Bright), an illuminated area appears on the face of Cathode tube (4). This area is usually off-centre and of irregular shape. (iii) By adjustment of trimmer screws (5) the illuminated area is moved to the centre of the tube and made uniformly circular in outline. (iv) By turning controls (6) the circular area is enlarged until its circumference coincides with the scale graduations on the edge of the Cathode ray tube face. (v) Knob (3) is turned to the right (Dim). The illumination of the Cathode ray tube is now extinguished. (vi) By means of knob (7) the receiver in now set to the transmitter frequency of the aircraft which is to be controlled (that is at 1.9 Mc/s. less than ground transmitter frequency). The frequency is given by the plotter. (vii) Switch (8) is now moved to down position for transmission of the Modulation Note ("Messton"). (viii) Switch (9) controlling test transmitter is then moved to the "On" position. This initiates transmissions from the station transmitter on a frequency automatically reduced by 1.9 Mc/s. The modulation note ("Messton") is audible in the operators' headphones. At the same time a point of light appears on the graduations of the Cathode ray tube (4) near the 13.7 km. graduation. (ix) Fine tubing knob (10) is now turned until the sound heard in the headphones is at maximum. Simultaneously with this adjustment the light point is seen to travel in a clockwise direction, reaching a turning point from which it retraces its path. This turning point coincides with the point of maximum sound reception and provides a visual method of tuning. (x) Phase switch (11) is now moved until the light point accurately coincides with graduation 13.7 km. (xi) Finally knob (12) (Amplitude width) is used to adjust the definition and intensity of the light point. (xii) The range measuring operator can now either switch on to the transmitter for continuous transmission by means of switch (13) or select either an automatic five or ten second transmission by means of switch (14). The latter system has recently been discontinued and on some Rechlin measuring units, switch (14) and the clock above it are not fitted. (xiii) To test R/T circuit the range-measuring operator depresses knob (15). Dial lamp (16) lights up. The operator must now hear his own conversation in his headphones. Turn knob (17) to adjust for correct audible strength. The R.M. unit is now tuned ready for use. (xiv) To go over to aircraft control, switch (9) (Test transmitter) moved to OFF position. (xv) If "Y" aircraft is being controlled then a light point will appear on the graduation of the Cathode ray tube. This gives the correct reading for the last digit. If, for example, the light point appeared on the 12 km. graduation, the digit "2" only is noted. When coarse-control knob (18) is pressed, the light point will spring forward by 10% of the real distance of the "Y" aircraft. That is, if the point advanced by 6.2 km., the correct distance of the "Y" aircraft could be 62 km. (xvi) The tuning transmitter referred to in (viii) forms part of the range-measuring apparatus, and superimposes its own transmission of 1.9 Mc/s. on to that of the station transmitter. This results automatically in a reduction of 1.9 Mc/s in the frequency of the station transmitter. "Siemens" Range-Measuring Unit. 33. The "Siemens" unit (Sketch IV) is found on "Y" control stations controlling night fighters. It is said to permit readings to an accuracy of 200/250 metres, allowing night fighter aircraft lacking search gear to be directed close enough to their target to obtain visuals. 34. The tuning and operation of this unit is effected as follows:- (i) Main switch (1) to "On" position. Dial lamp (2) lights up. (ii) Select frequency by means of knob (3). Instruct operator of station transmitter to transmit (a tuning transmitter is not incorporated in the Siemens unit). (iii) Switch (4) moved to "On" position. (iv) Switch (5) to "On" position, modulation note now being transmitted. Green dial lamp (6) lights up. (v) Tune for maximum audible signal strength by means of fine control knob (7). (vi) Turn knobs (8) and (9) until an image appears in the Cathode ray tube (10). Knob (8) controls light intensity and knob (9) controls definition of image. (vii) Control (11) now turned until the shape of the illuminated area in the Cathode ray tube is approximately circular. (viii) Using switch (12) (Wechselspannungs Diode) and switch (13) (Wechselspannung Empfänger) the approximately circular area now made fully circular and adjusted to a diameter of 3/4 cm. (ix) Control (11) now turned until the accurate reading pointer (14) records 13.7 km. The circle on Cathode ray tube (10) should now have become a line approximately at an angle of 45° from left bottom to right top of the face of the tube. If the circle shrinks only to an ellipse, trimmer knob (15) is used to reduce the ellipse to a line. (x) Switch (17) now moved down to coarse reading position. Turn knobs (18) (Intensity) and (19) (Definition) until a sharp image appears in Cathode ray tube (20). (xi) The coarse reading pointer (22) is then moved to the 413 km. position by turning control (11). The image in tube (20) should now be a line. If not, adjust by means of trimmer screw (21). (xii) This completes the tuning of the Siemens unit. "Y" control can commence as soon as the receiver frequency is lowered by 1.9 Mc/s. to bring the receiver frequency in line with aircraft transmission. (xiii) To take over control of an aircraft the following procedure is carried out:- Switch (17) moved to bottom coarse setting position. Control (11) turned until blip appearing in left tube (20) forms a diagonal line. If switch (17) now moved up into up (fine setting) position the line disappears in left tube and reappears as a flat ellipse in the right tube (10). On slightly turning control (11) the ellipse is converted into a line. (xiv) Distances can now be read off. The coarse reading scale is calibrated to read from 0 to 500 km. in 5 km. intervals. The fine reading scale has calibration readings from 0 to 100 km., which are divided, according to P/W, in 250 metre graduations. A very skilled operator is said to be able to estimate fairly accurately to 100/200 metres. (xv) As the distance of the aircraft varies, control (11) has to be used to maintain the blip in the form of a thin line. After the first setting, the coarse reading is only taken again at intervals. (xvi) Adjustment of the fine control knob (7) of the receiver unit as described under (v) also controls the "steepness" of the line image in the Cathode ray tube. The position of maximum steepness coincides with maximum audible signal strength and represents the turning point of the line image. This provides a visual check for tuning correctly. (xvii) The controls shown at the bottom of a Siemens unit are not touched by the operator. They are set by the makers of the instrument initially, using Deutschlandsender transmissions. (According to one captured document, a special transmission at 1040 hours daily by Deutschlandsender can be used for this purpose). The controls are subsequently reset by special test personnel. AIRBORNE R/T EQUIPMENT. 35. The R/T set used in Y-controlled aircraft is a modification of the FuGe 16-Z, in which the receiver unit of the set is linked to the transmitter unit in such a way that all signals received on the carrier frequency ("Gemeinschaftswelle") are automatically re-transmitted on another lower frequency ("Messwelle"), which is usually 1.9 Mc/s. below the first. 36. The automatic re-transmission of all signals received enables the aircraft to be plotted by bearing and range measurement without any reference to the personnel of the aircraft. 37. Two modifications of airborne FuGe 16-Z R/T sets are used in the "Y" procedure. FuGe 16-ZE. 38. The original modification of the FuGe 16-Z used for Y-control was the FuGe 16-ZE, which incorporated the "Zielfluggerät" (Z). 39. This set had the disadvantage that it caused a phase displacement ("Eigenphasenverschiebung") equal to a reading of 13.7 km., which had to be allowed for in the calibration of Siemen or Rechlin range-measuring units working in conjunction with it. FuGe 16-ZY. 40. In this modification of the FuGe 16-Z, the phase displacement of the apparatus is eliminated. Hence, when using Rechlin range-measuring unit, an attachment to this equipment is used which has the effect of cancelling the calibration allowance of 13.7 km., and causes the light point on the Cathode ray tube to start all readings from the zero graduation on the tube. 41. When the Siemens range-measuring unit is used in conjunction with FuGe 16-ZY, a second pointer marked "Y" is fitted in the former apparatus on the fine and coarse reading dials, in addition to the existing pointer marked "E" on both dials. The pointer marked "Y" added to the accurate reading scale is set back (to the left) of the pointer marked "E" by a number of scale graduations corresponding to the reading of 13.7 km. Therefore, when pointer "E" of the Siemens unit is on the 13.7 km. mark, the pointer "Y" is opposite the zero graduation. The additional coarse-reading pointer is similarly set back to approximately the 413 km. graduation, so far as P/W can remember. A.D.I.(K) S. D. Felkin. 25 Sept. 1944. Wing Commander." |
G.A.F. SIGNALS INTELLIGENCE
"SECRET A. D. I. (K) Report No. 402/1945
THE FOLLOWING INFORMATION HAS BEEN OBTAINED FROM P/W AS THE STATEMENTS HAVE NOT AS YET BEEN VERIFIED, NO MENTION OF THEM SHOULD BE MADE IN INTELLIGENCE SUMMARIES OF COMMANDS OR LOWER FORMATIONS, NOR SHOULD THEY BE ACCEPTED UNTIL COMMENTED ON AIR MINISTRY INTELLIGENCE SUMMARIES OR SPECIAL COMMUNICATIONS. G.A.F. SIGNALS INTELLIGENCE IN THE WAR – I. Organisation. 1. This report is the first of a series of ten comprising a study of the G.A.F. Signals Intelligence Service from the time of its inception onwards. Beginning with the broad principles and organisation, this series will cover the early history, the monitoring of signals and radar, countermeasures, cryptography, advance warning and route tracking, and intelligence of callsign and frequency systems. In some cases the various fronts in the war will be taken separately and dealt with in greater detail. 2. The information has been obtained mainly from the interrogation in England of senior staff officers of Abteilung 3, General Nafü and of Chi-Stelle Ob.d.L.; further evidence from captured O.K.L. documents has, however, been helpful in supporting these interrogations. FOREWORD. 3. One outstanding characteristic of the G.A.F. Signals Intelligence Service as reflected in P/W statements and captured documents is its constant improvisation and reorganisation to enable it to cope firstly with continually expending and later with contracting but more highly complex theatres of operations. This improvisation was clearly the natural result of the progress of the war as a whole, and had its origins in the Germans original calculations that their Blitzkrieg methods would finish the war quickly; this basic concept of a lightning war gave birth to a correspondingly short-term Signals Intelligence organisation. 4. Up to 1940 emphasis was necessarily laid on the tactical rather than the strategic side of the war, its external manifestation being the preference given to R/T rather than W/T traffic. The monitoring of W/T traffic hypothesises the existence of a large and efficient cryptographic organisation, and despite creditable achieve - ments by certain sections of the Chi-Stelle Ob.d.L. and the W-Stelle it is clear that a completely satisfactory central crypto Organisation did not exist. 5. As the war fronts expanded, the Signals Intelligence Service tended to become decentralised, so that as much work as possible should be done near the intercept stations. This of course demonstrated a considerable degree of elasticity in organisation, but it is obvious that it was forced on the Germans by sheer geographical necessity and by the diversity of problems presented by such different enemies as the Russians and the Western Allies. 6. The activity of the G.A.F. Signals Intelligence on the eastern front most nearly approximated to the original German concept in so far as Russian air activity was chiefly in support of the army, and the Signals Intelligence was able to concentrate on R/T and D/F. Russian radar was very elementary compared with the centimetre radar of the Anglo—American allies, hence the chief problems on the eastern front were those of distance rather than technical complexity. 7. By way of compensation for the inferior cryptographic results, the degrees of efficiency achieved by the G.A.F. D/F service was extraordinarily high, many of their best results being obtained by this means. It is certain that a large proportion of their most valuable long—term intelligence was obtained from D/F rather than cryptographic results (cf. Part V). The one is admittedly an inferior substitute for the other, but it is impossible to over-emphasise the contribution of the G.A.F. D/F service to strategic intelligence. 8. It will be seen in Part II of this series of reports how the origin of the German Signals Intelligence Service was due to an accident occurring, shortly before the battle of Tannenberg in the last war, and how it was developed in a desultory manner until the collapse in 1918. But in 1924 a small party of civil servants did their best to salvage what they could of the former Imperial Army's "Y" Service by studying current cryptographic problems and evaluation methods. 9. When the G.A.F. was expanded in 1936, it was able to utilise the signals intelligence and intercept experience gained by its Army counterpart; the Army's tendency was, however, centrifugal, each theatre of operations and major unit, such as Army Group, Army, Army Corps staff and even Divisional staff having its own almost self-contained Signals Intelligence unit. This army organisation was copied fairly faithfully by the G.A.F., so that all major units of the G.A.F. had their own Signals Intelligence organisation, the best-known of these in the first phase of the war being the Ln. Rgt. Legion Condor Nr. 3 working with Luftflotte 3. 10. It is almost a truism that Signals Intelligence has its greatest value when a war is going badly and is of least importance when all is going well. Thus Germany’s lightning successes were a great handicap to the future development of its Signals Intelligence, for they rendered almost superfluous the help which it could have given if duly appreciated and developed. All that seemed necessary was to listen to enemy R/T traffic while the German Army and the G.A.F. were hammering their way forward, so that as late in 1942 Referat B found it very difficult to induce certain intercept stations, to cover valuable but not so productive W/T frequencies rather than very productive R/T frequencies (cf. Part V). 11. Relations between intelligence sections and cryptographic sections working together appear, according to several of the present P/W, to have been none too cordial, as the former accused the latter of not getting the results which they could have done with greater effort and which they stated were not nearly as good as those achieved by the army. The real reason was not the incompetence of the individual cryptographers so much as the fact that they were not supplied with a sufficient depth of W/T traffic and that the crypto service should have been centralised; the output of a large centralised crypto service exceeds the sum total of the contributions of its individuals members and is higher in quality. 12. It is possible that this centralisation may have been achieved had the war taken a different course, but when the protraction of the war carried operations to widely separated fronts, the Signals Intelligence Service, always closely connected with the operational commands, began to be diffused. The first unit to move into remote parts was III/Ln. Rgt. 5, with W-Leit 5 as a nucleus (later Ln. Abteilung 355) started to operate with Luftflotte 5 at Oslo about the middle of May 1940, and continued to monitor both Anglo-American, and Russian traffic and radar transmissions in that area until the end of the war. (cf. Part I.) 13. The opening of the campaign on the eastern front in 1941 made an expansion of the Signals Intelligence service in that theatre absolutely necessary to cover the enormous front involved. 14. The front resolved itself into three major sectors - the Leningrad, Moscow and Southern Sectors. These sectors coincided to a certain extent with the static intercept stations of Insterburg (later Kobbelbude), Glindow and Pulsnitz of 1936-1937 and the later I, II and III Abteilungen respectively of Ln. Rgt. 353. On the southern sector a considerable volume of information will be found in Part No. VIII of this series. Very little information is available from P/W’s. on the central and western Sectors. 15. The war in Italy developed into a war very much on its own from the Signals Intelligences point of view, excepting from a technical and equipment aspect, where information obtained in one theatre of operations was of necessity of value to all theatres. Certain cryptographic results, as for example the grid system mentioned in Report V, obtained in this theatre was of value later on the Western Front. 16. It must be clearly realised that the G.A.F. Signals Intelligence Service did not resolve itself into a large number of small self-contained units but that, just as the German armies were spread out ever more thinly, the expansion of the war compelled the service to become centrifugal and prevented it from achieving that degree of centralisation and concentration which would undoubtedly have increased its efficiency. 17. The technical ingenuity of the Western Allies and development of radar on the western front continually presented new problems for the G.A.F. Signals Intelligence, making the setting up of new specialised units very necessary. As Germany's war situation deteriorated so it naturally expanded its organisation to cover all forms of Allied radio and, especially, radar activity. Thus arose the Funkmessbeobachtungsdienst, which, although carrying out some of its initial experiments in the East, concentrated on obtaining as much intelligence as possible from radar transmissions in the West. 18. This side of G.A.F. Signals Intelligence continued to increase in importance to the end of the war and, because of the tightening of Allied R/T security especially, became equal in importance to radio interception. In this respect it is interesting to notice how units of the Ln. Rgt. Legion Condor No. 3 were gradually adapted to cope with these new developments as Funkhorch Regiment West, and how eventually towards the end of the war a comprehensive organisation which included all fronts was set up, but much too late to be of real value (cf. Part VIII). 19. When in 1944 deep R.A.F. bomber penetrations into Germany became possible, they were accompanied by a very complex system of countermeasures and "spoof" attacks, very largely carried out by 100 Group. Thus the Signals Intelligence Service was further expanded by the inclusion of specialist radar technicians. Specialisation became the order of the day and each unit was allocated a specific function. Thus Ln. Rgt. 351 became responsible for monitoring Allied air activity in the West - except for heavy bombers, which became the primary task of two specialist Abteilungen 356 and 357. 20. No aspect of Allied countermeasures was more important than radar jamming, both passive and active (Window and noise modulation). This became so important as a potential means of obtaining early warning and route-tracking that a special Abteilung (359) was set up to deal with it. 21. The channels of communication varied according to the type of traffic involved. In the case of low-grade R/T or W/T tactical traffic, as for example A.S.P. traffic, the work was often done entirely on the fighter unit as in the case of the Horch Verbindungskommandos (= warning squads) described in Part V. As far as strategic bombing was concerned, a much more complicated system was necessary to coordinate the results of all forms of radio interception, radar observation and countermeasures. Where the work was being done within the framework of the Signals regiments, results were passed from the intercept units to the Meldekopf and thence to the competent fighter authorities, usually the Zentrale Gefechtsauswertung of Jagdkorps I, and ultimately to the Operations Staff via IC who co-related the results of signals intelligence with other forms of intelligence (see A.D.I.(K) 394/1945). 22. Always bearing in mind the fact that the picture of the G.A.F. Signals Intelligence Service was constantly changing in conformity with the changing war situation, the Appendices to this report set out the functions, locations and chains of command of the Regiments and Abteilungen of the Service. 23. Appendix I shows the connection between the component parts of the regiments and the referats of Chi-Stelle Ob.d.L., and the relations on a higher level with the Army and Navy Signals Intelligence Services, the Funkleitstand, the Leitstelle der Funkaufklärung and the G.A.F. Operations Staff IC. 24. Appendix II illustrates the expansion of Signals Intelligence in the West from its beginnings in Ln. Rgt. Legion Condor No. 3 in 1941 to the Funkhorch Regiment West in 1942, and then to its final form of Ln. Rgt. 351 and Ln. Funkaufklärungs Abteilungen 356 and 357 in 1945. 25. The final form of the chain of command in 1945 is shown in Appendix III. The radar observation service had by this time become so important under Abteilung 3, General Nafü, that it had to be coordinated in service matters along with the ordinary radio intelligence by a still higher authority. FUNCTION, LOCATION AND COMPOSITION OF UNITS. Ln. Rgt. 351 (Formerly Funk Horch Rgt. West). 26. The germ or this Regiment lay in the Ln. Rgt. Legion Condor No. 3 at Paris-St. Cloud in 1940/1941. Its function was to observe the Allied Air Forces in the West, excepting for the heavy bombers, which was done by Ln. Funkaufklärungs Abteilung 357 in co-operation with 356. 27. Its chief interest thus lay with the R.A.F. 2nd T.A.F. and U.S. IX Air Force, whereas R.A.F. Bomber Command and the U.S. 8th Air Force were dealt with by the specialist Abteilungen (356 and 357). To all intents and purposes Ln. Rgt. 351 was responsible for monitoring the combat areas, but it was not always possible in practice to avoid overlapping on someone else’s territory, especially as work was often duplicated by the Ln. Rgt. organisation and the evaluation sections of the Chi-Stelle Ob.d.L.; Referat 5, for example, was housed at Limburg in the same building as Ln. Rgt. 351. and was also employed in supplying intelligence directly to the IC of the Operations Staff. 28. Ln. Rgt. 351 consisted of 3 Abteilungen - I/351 at Limburg II/351 at Heidelberg and III/351 at Burg Schwalbach. I/351 was composed of an evaluation Company (25/351) a W/T Company (26/351) a Technical Company and a short-rang intercept company for picking up A.S.P. traffic, etc. The second and third Abteilungen had 2 - 3 shortwave reception companies. 29. The tactical R/T, W/T and Fu.M.B. messages were sent at once either by landline, teleprinter or, where not available, by R/T to the appropriate H.Q.s of the G.A.F., the Army and the Navy, as well as to the Zentrale Gefechtsauswertung at Jagdkorps I. This was done by Meldekopf at 25/351 (The origin of the Meldekopf is discussed in Part V of the present series). 30. The organisation of Ln. Rgt. 352 (Italy and Yugoslavia), 353 (Eastern Front) and Ln. Rgt. 355 (Norway) will be dealt with in special reports as they became special problems on their own with less direct influence on the course of events in the West. Ln. Abt. 356 (Formerly Funkaufklärungs Abteilung Reich). 31. Abteilung 356, with its H.Q. at Berlin-Wannsee, consisting of five Kompanien - 1/356 at Wannsee, 2/356 at Hamburg for monitoring approaches to the North-West and North, 3/356 and 5/351 at Stuttgart- Böblingen for incursions to the South and 4/356 for watching the U.S. Fifteenth Air Force. This Abteilung was a pure radar observation unit, operating within the Reich. Its task was to monitor and evaluate Allied airborne radar transmissions for the use of the Reich defence authorities in route-tracking of raids. The individual outstations transmitted the results of their observations to their Meldekopf for use in the air situation picture. Ln. Abteilung 357 (Formerly I/Ln. Fu. H. Rgt. West). 32. Abteilung 357, consisting of six Kompanien with H.Q. at Heiligenstadt/Harz, was responsible for monitoring the Allied heavy bomber formations and had to provide early-warning and route-tracking data for use in the defence of the Reich. The results of observation by this Abteilung were evaluated by Meldekopf I, who passed them on to the central report centre at Jagdkorps I. FINAL ORGANISATION. 33. In the final stages of the war the following radio intelligence units were in operation:- West. (a) Ln. Funkaufkl. Abt. 351 with three Abteilungen. Task: Observation of Allied Air Forces in the West. (b) Ln. Funkaufkl. Abt. 357. Task: Observation of the heavy bombers and route-tracking in collaboration with Ln. Abt. 356. Germany. (a) Ln. Funkaufkl. Abt. 356. Task: Following routes of enemy formations over Germany (cf. Ln. Abt. 357). (b) Ln. Funkaufkl. Abt. 359. Task: Radar jamming in the West and in Germany. (c) Ln. Funkaufkl. Abt. 350. (with Chi-Stelle Ob.d.L. and Funkleitstand Ob.d.L. Task: Concentration and final evaluation of all radio intelligence. (d) Ln. Abt. 358. Task: Training of replacement personnel for the radio intelligence units. South (Balkans and Italy). Ln. Funkaufkl. Rgt. 352 with 3 Abteilungen (Major FEICHTIER). Task: Observation of Allied Air Force in the Mediterranean. EAST. Ln. Funkaufkl. Rgt. 353 with 3 Abteilungen (Oberst DICK). Task: Observation of the Russian Air Force. North (Norway) Ln. Funkaufkl. Abt. 355. Task: (a) Observation of the Allied air forces over Norway. (b) Observation of the Russian air force in Northern Norway. - - - - - A.D.I.(K) and S. D. FELKIN. U.S. Air Interrogation. Group Captain. 25th October 1945" |
General der Nachrichtenführer MARTINI
"A. D. I. (K) Report No. 334/1945
THE FOLLOWING INFORMATION HAS BEEN OBTAINED FROM P/W AS THE STATEMENTS HAVE NOT AS YET BEEN VERIFIED, NO MENTION OF THEM SHOULD BE MADE IN INTELLIGENCE SUMMARIES OF COMMANDS OR LOWER FORMATIONS, NOR SHOULD THEY BE ACCEPTED UNTIL COMMENTED ON AIR MINISTRY INTELLIGENCE SUMMARIES OR SPECIAL COMMUNICATIONS. THE GAF SIGNALS ORGANISATION IN THE WAR. 1. This report results from the interrogation in England of General der Nachrichtenführer MARTINI, the Director General of G.A.F. signals from the time of the formation of the Luftwaffe until the end of the war. A feature of this interrogation was General MARTINI's rather surprising lack of detailed knowledge of signals and radar equipment in use in the Luftwaffe, but his knowledge on matters of broader policy of the signals organisation was naturally considerable. 2. The gap in his detailed knowledge has to some extent been filled by the chiefs of his subordinate formations, and it is intended in due course to issue a further report dealing with employment of radio and radar equipment. The present report confines itself to the main events during the war as they concerned the signals organisation, and shows that General MARTINI himself was not free from the intrigues which beset the whole of the General Staff. 3. The information has been divided into five parts, each of which is, as far as possible, dealt with in historical sequence; the parts are:- 1. Expansion of the G.A.F. Signals Organisation. 2. Navigational aids for G.A.F. bombers. 3. Defensive radar. 4. The success of Window. 5. Wireless intelligence and Signals developments. I - EXPANSION OF G.A.F. SIGNALS ORGANISATION. 4. To meet the growing needs of the G.A.F., General MARTINI developed the Signals Organisation from a small force with about 300 active officers at the outset of the war, to an army of about 350,000 of which 10,000 were officers and 100,000 women. 5. In the early autumn of 1940, GOERING, appreciating the part played by G.A.F. signals, ordered the force to be doubled. As Germany conquered fresh territories the Signals Organisation had to be constantly expanded. Early Campaigns. 6. General MARTINI was of the opinion that all the early German campaigns were prepared with great speed. When the German marched into Austria, he and General Feldmarschall von REICHEMACH were at a radio conference in Cairo. Neither of them had the slightest idea that Austria was to be invaded. They were both informed at Cairo that German troops had marched into Austria. Similarly, General MARTINI heard only at the last minute that German troops were to invade Czechoslovakia. 7. Some days before the Polish Campaign was opened, German land-air exercises were being carried out on a large scale, and the G.A.F., signals organisation was assuring interservice communications, in particular between RICHTHOFEN's Stukas and the Army. On the outbreak of war considerable strain was put on G.A.F. Experimental Regiment KOETHEN at the last minute, so as to ensure satisfactory communications for the Stukas in Poland. The British declaration of war came as a general surprise and created great uneasiness. 8. General MARTINI was emphatic in maintaining that he was informed of the intention to invade Norway only six to eight days in advance. He doubted whether HITLER had told more than a very few people of his intentions beforehand and he asserted that everybody appeared to be taken by surprise as arrangements were kept "terribly secret". 9. As soon as General MARTINI was informed of the intended campaign, he flew to his headquarters in Hamburg and selected his best officers for organising communications. They worked at high speed day and night for six days. The organisation proved exceptionally difficult because all the details of the plan had to be kept secret. It was decided that the Army Navy and Luftwaffe would all work on the same frequency at the half dozen points where landings were to be effected. 10. Every Ju.52 which the G.A.F. signals organisation could lay its hands on was transformed into a signals aircraft, and communications Trupps were also sent out on all the transport ships. The success of the G.A.F. communications, the General considered was largely due to the Ju.52 signals aircraft. Invasion of Britain. 11. General MARTINI would not commit himself about the time at which preparations were first made to invade England. Once the Germans held the Channel ports a plan was evolved under the cover-word "Seelöwe" by which barges were assembled in the Channel Ports. The whole plan was so decentralised, however, that the various departments knew only what directly concerned them. For a long time General MARTINI had the impression that the whole plan was a feint. He estimates that the General Staff worked seriously on the invasion plan for two to three months. 12. The plan comprised landings in two different places, but he maintains that he was never told what these places were, and he is not aware that any date was fixed for the invasion. He is certain that if the date for the invasion was fixed and the plan called off, then the High Command deliberately kept up the fiction that it intended to invade England for months after the whole thing had been shelved. Russian Campaign. 13. Support was given to the above contention by the General when he stated that he was informed at least six months ahead of the High Command's plan to invade Russia. Since the Germans wished to avoid fighting on two fronts, the plan to invade England must have been postponed indefinitely at any rate before 1941. When he was informed of the Russian invasion plan, General MARTINI discussed his requirements at a conference with HITLER. 14. This was one of the two or three occasions on which he had personally to report to HITLER. He worked out a plan to build six lines of communication advancing into Russia, each manned by one signals regiment. This required a considerable amount of material and transport. Generaloberst JESCHONNEK appreciated that General MARTINI’s requirements were justified, but the Army put up objections. 15. At the inter-service conference with HITLER which ensued, General MARTINI stated his case. "How quickly will you be able to construct your lines of communication?" HITLER asked him. MARTINI replied "30 kilometres a day". HITLER interposed; "That is far too little. Forty kilometres of railway will be built per day!". 16. MARTINI said that by putting down one telegraph line instead of two, he could assure the construction of more than 40 kilometres a day. HITLER then sanctioned all his requirements, telling the other services not to under-estimate the value of signals communications. 17. A unified method was adopted for signals construction in the Russian advance; field cables were first laid, then ordinary telegraph wires. Inter-service and fast communication such as Met. reports were sent by wireless. The system of G.A.F. Army Liaison officers used in Russia was modelled on that worked out by the Germans in the Spanish war. 18. Telegraphic communications were as a rule reserved for communications between O.K.L. and the Luftflotten, between the Luftflotten and the Fliegerkorps, and between the Fliegerkorps and Army Staff. 19. The German land lines were tapped by the Russians. General MARTINI regretted that the Germans had never succeeded in making a secure telephone scrambler. Ha said that towards the end of the war a satisfactory apparatus was found in a British or American aircraft. He had it tested and found it good. 20. Land lines in Russia also suffered considerably from partisan action. They were guarded every 30 to 50 kilometres by posts of 8 to 12 men, but guard duties were particularly difficult in forested country. When one line was cut, communications were switched onto one of the other lines or put over wireless links. Despite these difficulties, regular communications were maintained throughout the campaign. II – NAVIGATIONAL AIDS FOR BOMBERS. Development of Bombing Beams. 21. At the beginning of the war the G.A.F. tended to neglect its defensive organisation and concentrated on the offensive, General MARTINI was not responsible for navigation as such, but for high frequency radio as an aid to navigation. In 1933 he had calculated that with the navigational aids at his disposal, mainly D/F and compass, he could obtain an accuracy of only about 50 kilometres at is distance of 500 kilometres. 22. At the end of 1933, Dr. PLENDL, who had been introduced to him by the Technisches Amt, told him that if the funds were placed at his disposal he could in some years' time produce, a navigational aid with an accuracy of 500 metres at a distance of 500 kilometres, Feldmarschall MILCH placed the means at his disposal. After several years PLENDL completed his apparatus, and experiments were conducted on the X-System by Versuchs Regiment KOETHEN with the bomber Gruppe which later became K.G. 100. 23. The first operations of the war with mobile X-Stations were on two bombing missions against a munitions factory in Poland. The factory vas foolishly bombed at the same time by ordinary bombers, so that the experts were unable to determine whether or not the X-System was a success. 24. The campaign was over so quickly that no other operational trials with X-beams on Poland could be made. Knickebein Beams. 25. After the Polish campaign, Knickebein and X Stations were constructed opposite the German-French frontier in preparation for the Western offensive. Kampfgruppe 100 was by that time thoroughly trained in the beam procedure, and many highly specialised Signals officers had been incorporated in the Gruppe as navigators. 26. The Norwegian campaign then took place, and Kampfgruppe 100 was thrown into it as an ordinary bomber unit. Most of the crews were killed, and the Gruppe was wasted. The specialists were scarcely required for the French campaign, but the Gruppe had to be re-formed completely with lesser trained crews for the attack on England. 27. The Knickebein system was used at the outset of the attack on England. The apparatus on the Channel coast had been hurriedly set up, however, and there were neither sufficient technicians nor material to make conclusive tests. Dr. MODEL, a former Reichspost official who died during the war, was taken over by the wireless department of the signals organisation and was chiefly responsible for developing Knickebein in collaboration with the Technisches Amt and Telefunken. 28. The crews using Knickebein soon reported that the beam was being diverted, and that British fighters were being vectored on to it. Several weeks were required to prove that the beam was really being diverted. After some weeks, experienced signals officers were sent out with the bombers and reported that countermeasures had in effect been taken by the British. "X" and Benito Bomber Beams. 29. Dr. PLENDL invented both the "X" and "Y" (Benito) systems. The "X" beams were developed under the signals organisation at Köthen by Dr. KÜNHOLD with K.G.100 and General - then Oberst - ASCHENBRENNER, an old and experienced pilot. The Benito system, on the other hand, was perfected by Dr. PLENDL at the Technisches Amt under Feldmarschall MILCH, and General MARTINI had nothing to do with it. 30. It was intended to train a whole Geschwader to navigate on the "X" system. After Kampfgruppe 100, acting as pathfinders for large bomber forces, had been attacking towns in Great Britain on the "X" system for a short time, however, Dr. PLENDL wanted to try out Benito in practice, which he regarded as the better system. 31. At that time Oberst ASCHENBRENNER's younger brother, who was the Kommandeur of Kampfgruppe 100, was ordered to take over III/K.G.26 which had been intended to fly also on "X". Dr. KÜNHOLD always considered the "X" system better than the Benito, and was annoyed with Dr. PLENDL for introducing and pushing the Benito system. 32. P/W from III/K.G.26 stated in 1940 that the Benito system was introduced prematurely because of the countermeasures which the British had been taking against the "X" beam. General MARTINI, however, maintains that the causes for the early introduction of Benito were more complex. He said that he had been responsible for putting into practice the use of beams as navigational aids for bombers, and that he had considerable difficulty in overcoming the objections of the pilots and their commanders. 33. The pilots maintained that they could obtain better results by finding the targets themselves, and those who were obliged to follow the pathfinders felt that they were being relegated to subsidiary tasks. They reported that K.G.100 had bombed in the wrong place, and that they had found the right target by themselves. Despite the good results obtained with "X", anger against the system remained unabated. 34. The aim of operating two whole Geschwader on beams against England was not achieved because of initial distrust and British countermeasures and later because the bombers were earmarked for the Russian campaign. The Benito system suffered chiefly from British interference of the R/T. 35. General MARTINI himself realised from the outset that the beams could be interfered with from Britain, and favoured the introduction of several systems to make countermeasures more difficult. 36. Thus, in the light of later experience, the Benito system was introduced prematurely. The General points out that this was only the beginning of the high frequency war, and they lacked experience about the best measures for forestalling countermeasures. 37. When KG.100 was achieving its successes, GOERING enquired as to who was responsible for the "X" system. On hearing from MARTINI during a long talk on navigational aids that PLENDL had invented it, he said: "Then I shall promote him to Staatsrat!" (State Councillor). GOERING could not understand how the system had been jammed. MARTINI spent two hours trying to explain the procedure of jamming and countermeasures. GOERING asked a number of questions, but was afterwards clearly none the wiser. He grew very angry, and accused MARTINI of fiddling about with patchwork measures. 38. In reading the above statement it must be emphasised that General MARTINI was sometimes confused in his memory between the "X" and "Y" systems. Mobile "X" Stations in Russia. 39. Kampfgruppe 100 later flew in Russia with mobile "X" stations, which were set up with great speed. Cyklop System. 40. Towards the end of 1943, the Knickebein system was developed on a new basis with mobile stations under the cover name CYKLOP. This system was used extensively by Fliegerkorps IV, in Russia and was to have been set up on the Channel coast for attacks on England, but the General was not sure whether it was actually used. 41. Cyklop had a range of 300 to 350 kilometres as against the 450 kilometres of Knickebein. It was developed by Dr. KÜNHOLD at Köthen. Hitler Demands a Demonstration of the "X" Beam. 42. About the summer of 1942, when General MARTINI was at his headquarters in South Russia, he was suddenly ordered to fly over to Hitler’s general headquarters near Kalinovka some 12 miles away. HITLER had heard that the Krupps works had been hit in an attack at night throw ten-tenths cloud by R.A.F. bombers flying with navigational aids. He could not believe it, and said that there must have been a gap in the clouds; GOERING was troubled, and General JESCHONNEK - his Chief of Staff, who also had no faith in high frequency aids, was also sceptical. So HITLER ordered them to call in MARTINI. 43. Asked by HITLER whether such accurate bombing was possible on beams, MARTINI said it was. GOERING, who saw trouble ahead for himself, interposed saying: "Yes, my Führer, but we also have such systems." 44. HITLER asked MARTINI how the "X" system worked. In an attempt to simplify the explanation, MARTINI spoke about impulses and echoes. HITLER asked for more and more details, calculating for himself everything that MARTINI explained. The General thus found himself thoroughly involved and confused. 45. "Now I want to know", HITLER said with some impatience, "if you were to attack Munich main railway station from Leipzig on your system, whether you could hit it?" MARTINI, taking good care not to commit himself too deeply, said; "I should estimate that Munich is about 400 kilometres from Leipzig. If that is correct, and if the station is 1,000 metres long by 300 wide, then I believe that some of the bombs would hit the target." 46. HITLER replied: "I hope this is correct. I don't trust high frequency. I went on a flight in South Germany, and ended up in North Germany by mistake with your high frequency." He reflected for a moment and said: "I order a demonstration to be carried out with the "X" System in Germany, just as if it were an operation, to show me whether these things really can be done. 47. This was the last that MARTINI heard on the subject from HITLER himself, but a long time afterwards he was rebuked by GOERING for taking so long to prepare the demonstration; preparations actually took about nine months. 48. At the time the "X" apparatus was undergoing trials for improvements, and the aircrew who had used airborne apparatus had to be replaced in the aircraft, the "X" stations set up in the neighbourhood of Vienna, and new pilots trained. General MARTINI did not know all details of the trials, since they were put into the hands of Dr. PLENDL and the Air Officer for Bombers who was also Inspector for Navigation. 49. The actual bombing demonstration flight was from Austria to an unpopulated spot near Grafenwöhr in the neighbourhood of Bayreuth, and was a success, but it cost enormous effort. Disappointment over Erika. 50. Explaining why "Erika" stations had been built on the Channel coast but had not been used, General MARTINI said that the system proved far more difficult to perfect than had been supposed. 51. Moreover it necessitated a large airborne apparatus, and a very large ground installation, and this took years and years. In the final stages an inaccuracy was observed which had been previously overlooked. 52. There was besides the continual danger that it could be easily jammed. "I worried a great deal over it", the General said. 53. Professor von HANDEL, whose great passion it was, had claimed that it would be more accurate than the "X" system. He worked at it as feverishly as PLENDL worked on his "X" system. 54. The two men fell out and MARTINI went to great pains to get them to work together, and finally succeeded. He hoped that they would combine the "X" and "Erika systems, but this never happened. Sonne Beacons in Spain. 55. Talking of other air navigation systems, General MARTINI said that besides using Sonne beacons themselves in Spain, the Germans made over some Sonne apparatus to the Spaniards. III - DEFENSIVE RADAR. First Information on British Radar. 56. Discussing British and German ground radar, General MARTINI said he was aware before the beginning of the war that great radar stations had been put up on the coast of England, and that they had very long range. It was known that the impulses were 25, 50 and 1000, and that height measurements could be obtained. It was not known whether the radar could really determine the number of aircraft approaching. 57. Just before the war the Graf Zeppelin flew along the coast of England during an experimental flight. The main object of that flight was to test ultra-short wave receivers. Incidentally it was thought that British radar stations might be D/F'd. General MARTINI said he did not know exactly what experiments were made during the flight, but he had heard that the high frequency receivers were not satisfactory, and results were uncertain. First German Radar. 58. In General MARTINI’s opinion, the two men chiefly responsible for the invention of radar in Germany were Dr. RUNGE, of Telefunken, who worked on a 50 to 60 centimetre wavelength, and Dr. SCHULTES, of GEMA, who worked chiefly with 80 centimetre and 2.4 metre waves. 59. Radar apparatus was first developed in Germany by the Naval Experimental Institut and GEMA in 1936 or earlier. General MARTINI was shown a Freya by the Navy, and saw that it could achieve results over the sea. He hoped that the G.A.F. would be successful with it over land and foresaw that it could have a great feature in aircraft reporting, blind landing and other spheres. 60. Just before the invasion of Czechoslovakia he had a Freya placed in the Sudeten mountains. "I hoped", he said "that with our Freya in the mountains we would be able to pick up aircraft taking off in Czechoslovakia, but we failed to obtain any results". 61. At about the same time the firm of Telefunken began trials with Würzburg apparatus. They claimed that it could pick up aircraft, but their demonstration failed. 62. The General said that he had ordered about 200 Freyas and 800 Würzburgs for the G.A.F. before the war, but he had obtained only a small number by the time hostilities had begun. A very few Freyas were set up on the North Sea coast and these worked satisfactorily, being instrumental in causing heavy R.A.F. losses over Heligoland in the bombing attacks in 1939. 63. Freyas were not used during the Norwegian campaign, but were set up after the Luftwaffe had established itself on the Norwegian coast. The signals organisation was obliged to hand over all the Würzburgs intended for the aircraft reporting system to the Flak arm, because the radar apparatus brought out by Lorenz which was used for Flak aiming had proved a failure. Fighter Control. 64. From the reports of his Signals Intelligence Service, the General concluded that the R.A.F. aircraft reporting system and radar were used principally to aid the ground control of fighters. For a long time the Luftwaffe was unable to organise ground control of day fighters, because of the opposition of most of the pilots, who insisted on free-lance fighting. 65. The change was introduced very slowly and was influenced by the discovery by the German Signals Intelligence Service that the R.A.F. was using Pip-Squeak. The Pip-Squeak aircraft apparatus was later captured. The procedure seemed a good idea to the German pilots, who wanted a Pip-Squeak of their own, and began to realise the advantages of fighter control. 66. Actually, German industry had for a long time been working on a similar apparatus, but failed to bring out a satisfactory one. Later the Pip-Squeak apparatus was copied by the Germans, but it was never used operationally. 67. The organisation of radar for fighter defence suffered both before and during the war from inter-departmental difficulties and intrigue. 68. The main reason why radar was not developed earlier for ground control of fighters, General MARTINI said, was that until the summer of 1941 the Luftwaffe concentrated on offensive tactics to the neglect of fighter defence. The decision to subordinate aircraft reporting and radar to fighter ground control was reached at a stormy conference in Russia in the early stages of the campaign. MOELDERS and GALLAND insisted that the only way to improve fighter interception and cut down losses was to introduce satisfactory ground control. Research, Industry and Intrigue. 69. General MARTINI had a constant struggle to obtain the technical improvements necessary for carrying on the high frequency war. Except for a period of less than a year, during which he was given special responsibilities by GOERING, General MARTINI had no authority to make demands either from the scientists or from the industrialists. 70. Until 1937 he and his subordinates had been allowed to keep in close contact with the wireless industry, and to state their requirements, but merely for information. After that time Feldmarschall MILCH strictly forbade these contacts, and ordered that requests and enquiries should be made by the signals organisation through the Technisches Amt, of which he was head. Feldmarschall MILCH knew just as little about high frequency matters as GOERING. 71. MILCH issued his veto during a scandal in 1937 over the sale of the FUGe.7 to Switzerland, in connection with which a number of prominent scientists at Telefunken were arrested. P/W had the feeling that the scandal was worked up to prevent free collaboration between industry and the services, and to place the big firms under the supervision of the Technisches Amt. 72. Relations between MARTINI and MILCH were strained for years, even if the two men were outwardly polite to each other. MILCH was a great opponent of the General Staff, and particularly of the Tactical Führungsstab. He attempted to have the whole signals organisation placed under his command, but MARTINI resisted this strongly. 73. Thwarted in his empire-building, MILCH carried on an underground war against the signals organisation. On one occasion, in the presence of MARTINI, he said to GOERING: "It is a great crime that this signals organisation has been set up!" MILCH tried to prevent Luftwaffe officers from working in the Technisches Amt, and made liaison with MARTINI extremely difficult. For a time MARTINI had a representative at the Technisches Amt but he requested to be posted back to the signals organisation, saying that it had room only for engineers and not for officers. 74. MARTINI had engineers in his Experimental Regiment, the L.N. Versuchsregiment at Koethen, working together with the officers, but the engineers in the Technisches Amt refused to co-operate with them. When the Versuchsregiment brought out something new and stated its requirements, the Technisches Amt engineers said that their work was all wrong. 75. Even during the time that UDET was head of the Technisches Amt, MILCH in P/W’s opinion, really held the reins because of his position as GOERING's representative. 76. Feldmarschall MILCH made a point of co-operating with the signals organisation from the summer of 1941 for about nine months, during which MARTINI had GOERING's backing. Because of MILCH's opposition, MARTINI was still given no authority over the scientists or the industrialists, but he was given special powers to hold conferences with them, and with representatives of the Technisches Amt. 77. He had GOERING's authority to discuss his requirements in the utmost detail. When agreement had been reached on which developments could be carried out by the industry, the General had to make written requests to the Technisches Amt to put through the required orders. Thanks to GOERING's backing, MARTINI was able to force the Technisches Amt to place these orders. Role of the Versuchsregiment. 78. The Versuchsregiment had the task of conducting experiments with signals apparatus, and stating the technical or tactical requirements of the Luftwaffe with regard to it. Their reports went to the Technisches Amt. When the apparatus was delivered to the signals organisations the Versuchsregiment carried out operational tests with it and often made improvements. 79. The Versuchsregiment Koethen acted as a fillip to the wireless industry, sometimes producing new apparatus which the industrialists were unable to manufacture. 80. For example, the height measuring attachments on the Freya were built and produced by Koethen. Whenever work of this nature was handed over to Koethen, MARTINI had to obtain the sanction of the Technisches Amt. Despite the rivalry with the Versuchsregiment, this sanction would be given. Feldmarschall MILCH once or twice indicated that Koethen should be directly subordinated to him, but never pursued the matter. 81. General MARTINI described Dr. KÜNHOLD, the Technical Chief of the Versuchsregiment, as exceptionally able and at the same time very modest scientist. He was responsible for all the technical work done at Koethen. Oberst LÖWE, Kommandeur of the Regiment, was responsible for administration and discipline. He was also a good technician. He had formerly been a Captain in the Signals section of the Landes Polizei and had been taken into the Luftwaffe signals organisation in 1934. 82. The work of the Versuchsregiment at Koethen embraced all branches of the signals organisation; its work on radar was in practice restricted to ground apparatus. 83. The experimental station at Werneuchen restricted its research to radar and concentrated on airborne apparatus. Whereas Koethen, under the signals organisation, trained the experimental detachments which were incorporated in the signals regiments, Werneuchen was restricted to engineers and was subordinated to the Technisches Amt. 84. Oberstleutnant HENTZ, at the end of the war head of General MARTINI's Radar Section, the VI Abteilung, was formerly Kommandeur of Werneuchen responsible for its growth. 85. Co-operation between Werneuchen and the signals organisation was always better than that of the Technisches Ant itself with the signals organisation. Industry's need of Technicians. 86. At the end of 1941, it became obvious that the wireless industry did not have a sufficient number of technicians to carry out the requirements of the signals organisation. 87. Realising the danger of defeat in the high frequency war, MARTINI offered the industry up to 15,000 technicians from his Signals Regiment. He started by having 7000 to 8000 men transferred to industry, and then persuaded GOERING to transfer back to the industry and research organisations about 15,000 technicians from both the Army and Luftwaffe. 88. While the transfers were being carried out, the manpower crisis occurred on the Russian front and the process was reversed. Thus the best experienced technicians were being sent from industry to the Russian front, while less capable men were coming home and required at least a year to be trained. Countering of Allied Countermeasures. 89. The very nature of the high frequency war with countermeasures, measures to overcome countermeasures and constant changes in the apparatus, led to demands from the wireless industry which it could not meet. Thus the Versuchsregiment was frequently called upon by MARTINI to make the alterations itself. 90. For instance, when Freyas were manufactured with only one wavelength, MARTINI told the industrialists that it would be useless without a wave band. The industrialists replied that such a change would be colossal work which would require a very long time. "At any rate", MARTINI interposed, "bring out the next series of Freyas with two wavelengths, the one after with three, and gradually get a reasonable frequency band". The industrialists made objections, saying that the work was too fiddling. 91. MARTINI then ordered the Versuchsregiment to make the required modifications in the Freyas. Thus, despite British jamming from high-powered transmitters, the Versuchsregiment modified a sufficient number of Freyas for some to operate without being jammed. 92. Gradually all the Freyas were modified at Koethen under the covername "Voll-Wismar" and the wireless industry finally produced Freyas with an adequate frequency band. 93. Similar difficulties were experienced with FuG.16. The signals organisation asked the Technisches Amt for the apparatus to be constructed with 100 two-way channels, but through a misunderstanding it was produced with 100 one-way channels. 94. In the ensuing discussions, the industrialists considered that they would not be able to produce the apparatus with the required frequency band for about two years. FuG.25 and 25A. 95. The failure to organise the mass production of the German I.F.F., the FuG.25A, at an early date was attributed by the General to the weakness of his position in relation to the Technisches Amt. He was first shown the apparatus, which had been constructed by Dr. SCHULTHES, in September or October 1939. He was delighted with it and requested the production of two or three thousand. 96. These unfortunately were not produced, the General said, because too many people had a say in the matter. "Shortly afterwards a high official at the Technisches Amt told me quite by chance that 30,000 FuG.25 were already in production. That was terrible; it was my greatest worry. But Reichsmarschall GOERING said to me "It is the easiest problem of all and you haven't even solved that for me!" Switching on of I.F.F. 97. The General had heard the explanation from British bomber pilots that they kept their I.F.F. switched on to dowse searchlights, but he did not believe it. 98. He thought that there must have been some important reason this procedure which allowed the Germans to pick up the approach of R.A.F. bombers. He asked whether it was maintained with the object of eventually being of use to night fighter escort aircraft. He pointed out that it was of exceedingly great value to the Germans. The Panorama Apparatus. 99. About September 1942, somebody, whose name MARTINI never discovered, told GOERING that the signals organisation had neglected to develop the Panorama search apparatus. GOERING in a fit of temper told MARTINI that he had sabotaged the Panorama apparatus and MARTINI retorted sharply. That same day GOERING appointed Oberst KNEEMEYER as his Wireless and Navigation Officer, and put an end to MARTINI’s special functions in high frequency developments. 100. MARTINI continued to hold conferences with the scientists and industrialists on behalf of the Chief of the General Staff, but without GOERING’s authority he laboured under great difficulties. 101. The production of a German Panorama apparatus was delayed largely because at the beginning of the war tests were unsuccessful, and afterwards the wireless industry neglected it to try and satisfy other demands regarded as more urgent. The first Panorama, which was put up to the West of Berlin, could not be made to work and its development was shelved. 102. At the beginning of 1943, General MARTINI insisted that he should be shown what the apparatus was worth. He was told that the apparatus, which worked on one of the Freya frequencies, had not yet been perfected. He sent two members of his staff to try and overcome the technical difficulties and three months later he was asked to inspect the apparatus as it was at last working. He spent two hours looking at it, but the demonstration failed. 103. A second prototype, which worked on decimetre waves, was burnt out just after being completed. Centimetre Wave Research. 104. The failure to develop radar on centimetre waves was due, General MARTINI said, partly to Feldmarschall MILCH’s lack of understanding of the problem, and partly because the wireless industry could not cope. He himself had demanded in 1937 that research should be carried out on centimetre waves. 105. Staatsrat ESAU made experiments with ultra-short waves at first with a milliwatt, which he later increased to a watt. The scientist said that it was not his business, but that of the industrialists to continue the work with higher power. The industry, however, had too many other orders on hand, and Feldmarschall MILCH, who could have put the research in the hands of the Technische Amt, did not realise the implications of the high frequency war. 106. In the summer of 1942, GOERING suddenly decided to replace Dr. ESAU by Dr. PLENDL, whom he promoted to the rank of Oberst Ingenieur, saying: "I appoint you chief of all high frequency research in Germany". Dr. ESAU complained to General MARTINI of being cold shouldered, but the General had not even been informed of GOERING's decision beforehand. 107. General MARTINI made about 60 closely inter-connected requests for research on high frequency matters to Dr. PLENDL. He said that PLENDL's work as Chief of high frequency investigations was somewhat disappointing, and criticised him for spending too much time on organising, to the neglect of research. He did not put the same energy into this work as he had done in the development of the "X" and "Y" systems. However, the General did not agree with those critics who accused Dr. PLENDL of combatting the protagonists of the Egon system. 108. In 1944 GOERING became dissatisfied with PLENDL, and reinstated ESAU in his place. The old collaboration between ESAU and MARTINI was then resumed. The Egon System. 109. Dr. SCHULTHES, who first worked with GEMA for the Navy and later with Siemens, had reported early on that the Egon system promised great possibilities. At one of the General's conferences in 1941, he said that exact location up to 350 kilometres could be attained with Egon, but could not give a date for the perfection of the system. Nevertheless those scientists who were opposed to Dr. PLENDL advocated the immediate scrapping of the Benito fighter control system and the introduction of Egon. 110. MARTINI intervened, stating: "The problem is not so simple. We have built up the whole organisation for the Benito system which has definite advantages; it can be used not only for bombers but for fighters with very good results. We must develop Egon with all possible speed, but before it is ready to be used operationally it would be madness to do away with Benito. We must have both systems operating at the same time". 111. In General MARTINI's view, time has justified his point of view. The Benito system had proved itself thoroughly efficient for fighter control, and in the later stages of the war those controllers who used both systems were glad to check up one on the other. With the small fighter force to which the Luftwaffe was reduced, a small error in ground control was fatal. Capture of the British "Gee" Apparatus. 112. GOERING, who was in the habit of cursing the signals organisation, was particularly vehement when he heard that a British bomber had been captured with a fine apparatus on board which was an improvement on anything brought out in Germany. This was the "Gee" apparatus which the Germans named Hyperbel. 113. General MARTINI said that he learned a long time afterwards that the firm of Telefunken had actually worked out a similar system to "Gee" on long waves in 1939. Telefunken which had given the apparatus the cover name "Ingolstadt", had proposed developing it, but the Technisches Amt had turned it down because of an order previously issued forbidding work on any developments which could not be completed by the end of 1940. 114. The "Gee" apparatus was handed over to Koethen for examination and copies. The reason why Gee" was not jammed earlier, the General thought, was because of the German lack of ultra-short wave transmitters. It required a good nine months to construct apparatus, once the prototype had been completed. For a time, he said, the Germans considered that they were successful in jamming both "Gee" and "Oboe", but when these systems were used by the Allies with many wavelengths, the only answer was to build up a great system of jamming throughout Germany. This system was never completed. Jamming – The Feldberg Project. 115. The General recalled an attempt in 1945 to jam Allied airborne radar which ended in disaster. The first new highpowered German ground jamming plant, which was manufactured with great difficulty because of Allied bombing attacks, was finally all assembled inside a tower on the Feldberg with the object of jamming all wavelengths from the one place. 116. The work was carried out by the Reichspost "just as it were peacetime" without a thought to passible consequences of bombing. No sooner had all the apparatus been completed than the tower was destroyed by a fighter bomber attack. The case was brought before a court-martial. H2S Countermeasures. 117. The Germans were not successful in their ground countermeasures against H2S, because they were unable to get such apparatus as they had captured intact to work properly. The apparatus was technically in order, but despite repeated trials the navigators were unable to achieve results with it. Results were finally with a F.W.200 which was fitted with both the H2S and the "Berlin". When flying over the Mark Brandenburg in the spring of 1944, the aircraft crashed for some unknown reason. "Berlin" for Night Fighting. 118. It would have taken a long time, the General said, before "Berlin" could have been put into operational use for bombing on the same lines as H2S for which it was originally constructed. As the Germans were not carrying out bombing raids it was no longer important. It was therefor proposed to adapt the "Berlin" for night fighting, and as such it would have been used operationally within a comparatively short while. 119. The Germans had great difficulty towards the end of the war in constructing airborne apparatus such as "Berlin" small enough to fit into their aircraft. They had scarcely any fourengined aircraft, and the Ju.88 was not roomy enough. In the final stages the wireless industry had to concentrate on apparatus sufficiently small to fit into the Me.262. Me.262 Radar. 120. No Me.262 had flown operationally with radar, but a few successful trial flights had been carried out, using Neptun apparatus which was small to go into the aircraft without being unwieldy. 121. The type used was the forward-looking Neptun. The test aircraft crashed and the observer was killed, but the pilot reported that good blips had been obtained. Me.163. 122. No attempt had been made to operate the Me.163 with ground control. Kammhuber’s Night Fighter Belt. 123. Speaking of the development of German night fighter defences, General MARTINI said that General KAMMHUBER did not at first appreciate the value of radar. Before the latter had taken over the night fighter defences, he had distinguished himself as a good blind flying pilot, but he had no technical knowledge of radar. For that reason he organised the wellknown searchlight belt defending the western approaches to the Reich. 124. About two and a half months after KAMMHUBER had begun to work on the night fighter belt, MARTINI sent him six reporting companies which were then equipped with Würzburgs, because MARTINI considered that this would be the best way of organising night fighter defences. 125. The reason why the night fighter defence sectors were worked out in a perfect pattern was that KAMMHUBER, being a keen organiser, considered that he would benefit by their being all exactly alike. 126. Asked why KAMMHUBER did not organise his night fighter belt to rely on Würzburgs from the outset, General MARTINI said that he himself had not been consulted when the work began. GOERING had ordered KAMMHUBER to organise night fighting, without referring him to MARTINI. KAMMHUBER did not even know what to do with the aircraft reporting companies which MARTINI sent him; however, he studied the whole question of high frequency with much vigour, and soon reorganised the night fighter defences to depend on ground radar. 127. The reason why so many radars were put up on the Kammhuber belt was that the Germans at that time were using the old Würzburgs which could obtain satisfactory results only up to a radius of 35 kilometres. When the Würzburg Riesen were introduced, General KAMMHUBER kept the other Würzburgs for a time so as to maintain the pattern of his organisation throughout the night fighter belt. 128. KAMMHUBER preferred the Seeburg Tisch method of plotting to the Freya-AN system, because he said that the former method of control could be understood by all but the latter could be managed successfully only by special gifted officers. MARTINI was disappointed because he considered that there were enough capable young officers in his organisation to have worked with the Freya-AN. The Removal of Kammhuber. 129. The General said that he did not know exactly why KAMMHUBER was removed to Luftflotte 5. In his own words, taken from shorthand notes during interrogation: "It was a sudden decision of the Reichsmarschall and I imagine that he must have reached it after one of the officers had told him something or other. It happened during a big conference at Deelen during which the Reichsmarschall attacked me sharply because he was determined not to understand why I wanted to maintain the visual and oral aircraft reporting system as well as the radar organisation. I explained that it was important to know what types of aircraft were approaching when there were low-flying attacks. He would have nothing of it and was in a very bad temper. 130. "The next day he took General KAMMHUBER aside, and then came back saying that he was to be A.O.C.-in-C. of the Luftflotte in Norway. Possibly the reason for this was that the night fighters were not gaining so many victories. Outwardly the new post meant a great promotion, for he was a young officer, and as A.O.C.-in-C. he attained the rank of a General-Feldmarschall. 131. "I did not ask him what he personally thought about it. Perhaps he had expected to control all the fighter forces in Germany, and to have become an A.O.C.-in-C. like that. 132. "The change took place at the time of the appointment of a new General Staff. I was to have been thrown out also. They wanted to divide up my work, and I had made it a hard and fast rule that my organisation must not be split up, whatever happened. I had to insist on this several times, and each time said that if the organisation were split up, I should ask for another post. Finally on that occasion too, it was decided that I should..... 133. The Reichsmarschall did not understand the principles of night fighting, but discussed them a great deal with General KAMMHUBER just as he did with me. When I held a different opinion, I told him so quite openly. For a long time he listened to me, and then one day he refused to listen to me at all. It was roughly the same with General KAMMHUBER. He too used to state his opinion openly". IV - SUCCESS OF WINDOW. Not a Surprise. 134. The dropping of Window by Bomber Command over Hamburg in the summer of 1943 did not come as a complete surprise to the German signals organisation. For about a year engineers at the Technisches Amt had studied the question. The scientists had a suspicion of the danger to German defensive radar but said nothing because they did not wish to bring them-selves into disrepute. 135. Six months before the Hamburg raid their experiments had proved conclusively what a menace the metal strips represented. The information was passed to MARTINI, who handed GOERING a two-page report on the subject, pointing out what a terrible danger they might be. GOERING was so upset that he ordered MARTINI to destroy the document at once, and take the utmost precautions to prevent the enemy from learning of the discovery. 136. "It was thus extremely difficult", the General said, "to work out countermeasures because we dared not experiment with the little beasts for fear of their being discovered. Had the wind blown when we dropped the metal strips, people would have picked then up, talked about them, and the secret would have been betrayed". 137. When the Hamburg raid came there was great excitement because the signals organisation had not discovered any countermeasures. GOERING blamed MARTINI again, saying: "The British have now gone and used the metal strips, so they have surely got countermeasures against them and you haven't!" Window Countermeasures. 138. A few days after the Hamburg raid, two scientists independently worked out countermeasures to Window and the result was the Würzlaus attachment to the Würzburg and the Freyalaus attachment to the Freya. When considerable quantities of Window were dropped, the Würzlaus was swamped, however, but the Freyalaus still gave results. Finally a combination of the two, the "K-Laus", was tried out but was found difficult to handle. 139. The General admitted that no really satisfactory answer to Window had been found, and doubted whether there could be one if the strips were dropped in sufficient quantities and places. The Flak batteries never succeeded in using their own radar instruments when the Allied air force used sufficient Window or Chaff, but the aircraft reporting system was at least able to provide them with rough data on height end direction. 140. With Koethen Grau apparatus they managed for some months to get a rough picture despite Window. German night fighters were on the whole not too much affected by Window and at first it frequently even gave them a rough idea of where to find the bomber stream. Their task was then complicated by the countermeasures of 100 Group, R.A.F. Bomber Command, which General MARTINI described as outstandingly good. 141. Explaining the lines on which the Germans developed their radar defences, General MARTINI said that in order to obtain as early a warning as possible. They built bigger and bigger apparatus, as the range of the Allied bombers increased. The Germans thus gradually increased their warning range from 100 kilometres with the Freya to 300 kilometres with the Wassermann, the Mammut and the Elefant. The danger of jamming and bombing was fully realised but the Germans were glad to have the latter types of apparatus when the British introduced Window and airborne jamming, 142. Elefant proved particularly useful as it was not jammed for a long time. Results with Klein-Heidelberg were also good General MARTINI believed that the apparatus had been invented by Oberpostrat SCHOLZ, who had the chief merit for jamming British radar when the Scharnhorst and Gneisenau passed through the Channel. The General attributed the success of this operation to the fact that it was started with very slight jamming which was gradually and almost imperceptibly increased until it became effective. Wilde Sau Night-Fighting. 143. The fact that the Germans began to develop Wilde Sau free-lance night fighting at the very time that the R.A.F. introduced Window was largely fortuitous. Oberst HERRMANN was mainly responsible. He said that the night fighter had to take risks in German Flak areas and shoot down bombers caught by the searchlights or in the glow of the blazing target. He said he was quite prepared to do free-lance night fighting of this nature himself, and did so. 144. GOERING, seeing that far fewer bombers were being shot down because of Window, encouraged the younger night fighters to go up over the targets and fight. V - SIGNALS INTELLIGENCE AND SIGNALS DEVELOPMENTS. SIGNALS INTELLIGENCE. Work of the Intercept Service. 145. The German Signals Intelligence Service (Luft Aufklärungs Dienst) was under the operational command of Oberstleutnant FRIEDRICH, who was subordinate to MARTINI through Oberst MORGENSTERN; the officer responsible for discipline and administration of the service was Generalmajor KLEMME. Coverage of Allied signals was determined by the Intelligence of the Luftflotten in which the signals units operated. 146. GOERING himself was interested in the service and occasionally gave personal orders for some particular activity to be covered. l47. Results from the German Signals Intelligence had, according to General MARTINI, given high satisfaction to everyone until the last phase of the war, when the service, no longer able to cope with the enormous number of Allied raids or to keep track of the continually changing basings of Allied aircraft, also came in for its share of GOERING's displeasure. 148. Up to this point it had never failed to provide, from the Battle of Britain onwards, a current and exact Order of Battle of the British and later of U.S.A.A.F. formations, including subordinations, the number of squadrons operating in each sector, and their dispositions and strength. 149. Valuable information on Allied fighters was given by the interpreters, who were sent up with reconnaissance crews operating from Norwegian and Mediterranean bases. They were briefed beforehand in the locations of Allied fighter units in the operational area, and the frequencies on which the latter were likely to work. The low number of suitable men available, however, had confined their employment to reconnaissance aircraft. The General thought they would have continued to be valuable as long as air to air and ground communication remained insecure. 150. The Germans were able to recognise Allied preparations for taking off, not so much through the pilots' talk as by observation of small details in point to point traffic. The slightest carelessness in procedure between two ground stations, for instance, might suffice to reveal which networks were active. Then, even though the traffic itself remained unbroken, time and time again it became possible to draw definite conclusions concerning the operations involved by the comparison of traffics occurring in similar form. 151. The General admitted that sometimes the German intercept service was tricked by British spoof traffic. 152. The very high standard of R/T discipline shown by British pilots was held up by General MARTINI as a model for German pilots, who, as a result of the example began to show marked improvement in the later stages. He considered American pilots to be about the equal of the German pilots in this respect. Employment of Signal Aircraft. 153. General MARTINI thought that experiments with Signals Ju.52’s had begun in the Spanish war, but in any case exercises with them shortly afterwards had proved their worth, and they were used with success in considerable numbers in the Polish Campaign. 154. Later on, with fighter units being constantly switched from one area to another out of range of their home stations, the signals Ju.52's were used to pass information from Aircraft Reporting Station and ground radar to airborne fighter formations. 155. As the scale of Allied attacks increased, it became impossible to protect these signals aircraft on the airfields. Their signals equipment was therefor made portable, taken out on arrival at the airfield at which it was desired to operate, and set up some distance away. 156. Allied bombing was thus responsible for the abolishing of the signals aircraft, which was used in the later stages of the war as a transport aircraft. Liaison with German Navy. 158. All intercepted signals that concerned shipping were passed immediately to the German Navy, who controlled the costal observation posts. In general, liaison with the German Navy in signals matters was very close indeed, key personnel of both services and the Army often working together on the same problems. High Grade Cyphers. 159. The General did not think that Allied high grad Cyphers had ever been broken, although since he was only concerned with what came cut he could not speak with certainty. Allied Cyphers in general were very secure. 160. Prior to the North African Campaign the Germans themselves introduced the "Sägefisch" for communication over great distances in the event of cable being rendered unserviceable. 161. "Sägefisch" comprised a short-wave transmitter operating in conjunction with an automatic cyphering Machine; it was efficient only over distances of 250 miles or more. Messages were typed into the machine in clear, automatically encyphered and then transmitted. At the other end they were automatically received, decyphered and typed out by the machine also in clear, the entire operation taking only a few minutes. 162. Continual watch had been kept by the Germans on their Sägefisch traffic, and whenever possibilities of the Allies breaking down the cypher were observed, countermeasures were immediately taken to render it more secure. Defensive Measures. 163. Towards the end of the war, with the overwhelming superiority of the Allied air forces, special efforts were made to obtain the maximum efficiency from the German Intercept Service, which was accordingly brought into much closer co-operation with the Aircraft Reporting Service, employing visual and radar means for aircraft detection. 164. Radar stations and intercept stations finally worked together, both at Divisional and Sector Battle H.Q.'s. By comparison of the intelligence produced by both services, it was possible to obtain a more accurate picture of the air situation. In this connection, the General said that Allied bomber formations could be D/F's to within 1° of accuracy. 165. To ensure that German signals traffic could not help an eventual enemy to D/F German airfields, General MARTINI laid it down from the outset that transmitters must not be situated in their vicinity. Throughout Germany, therefore, the wireless transmitters were built at least 10 kilometres away from the airfields. One transmitter station was usually built to serve several airfields. To maintain land communications during bombing attacks the decimetre wave point-to-point system, Richtverbindung, for telephonic and/or telegraphic communications was extensively developed. 166. In Italy, Allied bombing frequently made it impossible for the Germans to move along the roads, and telegraphic communications were wrecked. The Luftwaffe, however, was able to help the Army out with its Richtverbindungen. Point-to-Point Communication. 167. The General said that a number of conversations on Richtverbindungen were held which should not have taken place, since this method of communications was not secure. 168. Another difficulty with the Richtverbindung system was that it could be seriously jammed. He believed that the jamming which actually took place was by chance, and that it came from airborne transmitters intended to jam the German ground radars. He even considered organising a raid warning system on the basis of this jamming. Spoof before D-Day. 169. Before D-Day the Germans were tricked by a spoof operation which gave them the impression that a big force was making for Fécamp. 170. Although many aircraft reporting radars along the coast had been put out of action by Allied bombing, the General claimed that there were still sufficient left to maintain the service. (He said that he was not responsible for the Naval Radar Service). • 171. During the last few days before the invasion, the radar operators were often misled to report that something was coming when nothing was there at all. This was partly due to the atmosphere, and the radar operators were accordingly warned to caution when reporting. 172. As a considerable number of jamming transmitters on the French coast had been destroyed by Allied attacks, the Germans had to achieve results with mobile ones which were to jam ground-to-air R/T. They were never used, having possibly been destroyed on the way to the coast or on their arrival. SIGNALS DEVELOPMENT. Allied Bombing. 173. The signals organisation suffered most through the Allied bombing of wireless valve factories; on the other hand the General did not think that decisive results could have been achieved, had the Allies made a concerted campaign exclusively against the valve industry. 174. The Germans started dispersing stocks after Telefunken and Lorenz had been severely damaged. A marked shortage of valves resulted, but according to the General the situation was never critical. The General admitted, however, that during the Mediterranean campaign, for a time fighter aircraft were delivered to Sicily without wireless apparatus. Low Quality of Radar Operators. 175. It was mentioned to General MARTINI that earlier in the war, when the Würzburg was captured on the French coast at Bruneval, the prisoners who were taken with the apparatus were found to have remarkably little technical knowledge. 176. The General ascribed this to the crisis in manpower among wireless technicians, which forced him to use unskilled men and later women as radar assistants. 177. Wireless technicians had to be trained within the signals organisation, because before the war there were no radio amateurs as in Britain and the United States. The activities of all amateurs had been suppressed in Germany "at the time of the Communist danger". Failure of HS.293. 176. Lack of success with the Hs.293 radio-controlled glider bomb was attributed by the General largely to two factors. Firstly, the Technisches Amt, which was responsible for its development and production, kept the weapon entirely for itself. Only when it was realised that there were not enough frequencies on the radio control of the bomb to make it immune from jamming, did the Technisches Amt feel obliged to bring the signals organisation into the picture. General MARTINI insisted on a number of alterations, but the Hs.293 was brought out before the radio control had been perfected to make it free from jamming. 179. Secondly, the Germans had not sufficient numbers of suitable aircraft from which the bomb could be operated. The Do.217 with which it was mainly employed was, moreover, extremely limited in range. 180. The high vulnerability of the Hs.293 to jamming was accepted by the Germans, who decided that it had best be used in a heavy surprise attack in an area where immediate observation by the Allies would be difficult. Norway was considered to offer best chances of success, and it was therefore a very unpleasant surprise to the General to learn that the bomb had been used in the Mediterranean theatre shortly afterwards. 181. Nevertheless, to render Allied countermeasures as difficult as possible and in order to camouflage tuning, radio stations were set up whenever the bombs were being used, and aircraft were employed with the bombers to transmit on other wavelengths while the bombs were being armed. 182. In spite of these precautions the General thought that the Allies might have succeeded in jamming the bomb, owing to the extreme simplicity of the wireless control. 183. Radio-controlled bombs had been conceived solely as an anti-shipping weapon, the HS.293 against large transport, the FX against battleships and armoured vessels of all sorts. They were afterwards relegated to uses for which they were never intended - against bridges and other land targets. Collaboration with Japan. 184. The extent to which the Germans gave their secrets to the Japanese was not known by the General. He said that early in 1945 HITLER ordered that all German technical secrets of short and medium term value should be given to the Japanese. 185. He said that no members of the signals organisation had left for Japan apart from those who were presumably in the Uboat which was intercepted by the U.S. Navy in the Atlantic. 186. From a visit to Germany paid by a delegation of Japanese officers. General MARTINI gained the impression that they were behind-hand in radar. A Japanese told him that they had apparatus with centimetre waves, but he could not remember the details. He regarded the Jagi aerial as very good, but did not know whether or not the Technisches Amt had received it from Japan. He was sure that the Japanese had received at least documents and photographs of German ground radar. A.D.I.(K)& U.S. Air Interrogation. S.D. Felkin 21st June 1945. Group Captain" |
G.A.F. INTELLIGENCE
"SECRET A. D. I. (K) Report No. 393/1945
THE FOLLOWING INFORMATION HAS BEEN OBTAINED FROM P/W AS THE STATEMENTS HAVE NOT AS YET BEEN VERIFIED, NO MENTION OF THEM SHOULD BE MADE IN INTELLIGENCE SUMMARIES OF COMMANDS OR LOWER FORMATIONS, NOR SHOULD THEY BE ACCEPTED UNTIL COMMENTED ON AIR MINISTRY INTELLIGENCE SUMMARIES OR SPECIAL COMMUNICATIONS. G.A.F. INTELLIGENCE IN THE WAR. Abteilung Ic (Chief of Intelligence). 1. The present report is the first of a series of three dealing with some aspects of G.A.F. Intelligence during the War and in the series of European incidents which preceded it. Whilst this report covers the vicissitudes of the two Chiefs of Intelligence during the major part of the War, Generalleutnant Josef ("Beppo") SCHMID and Oberst WODARG, the second and third reports will deal respectively with details of sources of intelligence and their value to the Luftwaffe Operations Staff, and with the working of Intelligence during the main incidents preceding the War and in the main campaigns of the War Itself. 2. The information has been supplied by Generalleutnant SCHMID, the Chef Ic from 1938 to 1942, Oberst WODARG, the Chef Ic from 1942 until February 1945 and Oberstleutnant KIEMITZ, who worked under both SCHMID and WODARG and finally took over the latter's post. Some additional information was supplied by Hauptmann ZETZSCHE, chief of one of the Groups in the Ic department of Foreign Air Forces West and from Oberstleutnant OHLETZ who, from January 1941 until March 1943, was Ic of Luftflotte 6 on the Russian front. 3. The main impression gained from these interrogations is one of two distinct phases in the fortunes of G.A.F. Intelligence, each the direct result of the War situation at the time. These two phases fall roughly into the periods of office of "Beppo" SCHMID and Oberst WODARG. 4. The handling of Ic by SCHMID for the furtherance of personal ends and as an obliging and gratulatory adjunct to the G.A.F. General Staff could find no impediment in the rising tide of German success. With the reversal of fortunes and the ever-widening gap between the wishful thinking or the General Staff and insistent reality at the fronts, however, the broad and easy path of SCHMID became a tightrope from which he inevitably fell. 5. It is noteworthy that SCHMID, the close friend of GOERING, departed to the command of Jagdkorps I with undiminished prestige, whilst WODARG, eclipsed by the glow of a former spurious glory, was left to struggle in evil times to obtain recognition of an unpleasant war situation. At times he was forced to the employment of amazing expedients in order to achieve this end. Since the acceptance of defeat could find no place in Nazi philosophy it was never possible for the German Intelligence, which had foreseen defeat as early as 1943, to achieve the prestige, facilities and effectiveness enjoyed by its Allied counterpart. THE FIRST CHEF IC - 1938 to 1942. 6. The 5th Abteilung was established as part of the G.A.F. General Staff on first January 1938 and was to collect information on foreign air forces and to build up target data for appreciation in air warfare. The new department was to combine and systematise functions previously the responsibility of a target data unit and of R.L.M. departments of foreign air forces. 7. Those two organisations were already known respectively as Gruppe II of the first Abteilung and the 5th Abteilung, and were manned by civilians and reserve officers who had large quantities of information from the foreign press and literature at their disposal, but worked with no clearly defined aims; their main policy seemed to be deliberate exaggeration of the strength of foreign countries it order to justify German armament. 8. An appreciation by Generalleutnant SCHMID of the achievements of these two organisations up to January 1938 will be found in Appendix I to this report. 9. The new 5th Abteilung was to be under the command of Generalleutnant, - then Major, - SCHMID, who since 1935 had been employed in a ministerial capacity and had no knowledge of foreign languages. He had, however, been recommended to GOERING by Oberstleutnant JESCHONNEK, at that time Chief of the 1st Abteilung of the General Staff. 10. The first task which SCHMID set himself was to replace his staff by younger and more suitably qualified officers, although these were difficult to obtain. The organisation of the 5th Abteilung, or department Ic of the Ops. Staff as it now became, is shown in Appendix II to this report. After the dismissal of SCHMID in 1944 the department was reorganised by Oberst WODARG to the form in which it remained until the closing stages of the war. This aspect is discussed later in this report and the new organisation appears in Appendix IV. 11. The main departments of SCHMID’s new organisation were set up as a first echelon at the Wildpark headquarters, and other departments as a second echelon at the R.L.M. in Berlin. For 21/2 years SCHMID and his staff lived and worked in the command train which was the "Robinson" headquarters. 12. By the outbreak of war intelligence departments had also been set up in the subordinate commands of the G.A.F., but choice and training of staffs were far from satisfactory, and it was not until 1942 that Ic (Intelligence) officers were appointed down to Geschwader and Gruppe levels. Even then the type of officers chosen reflected a lack of appreciation of the needs of Intelligence. 13. According to Oberstleutnant OHLETZ, the entire Ic service suffered from lack of experience when the war broke out, since the apparatus to meet the demands of war was not brought into being, until that time; from the technical point of view, however, Intelligence had played its part well up to that time, as, for instance, in that the target indices available at the outset were good, as were the political and geographical studies produced. 14. In spite of SCHMID's efforts to introduce younger men into Intelligence at the time when he took office, his specialist staff was still mainly composed of older reserve officers, the majority of whom were lacking in both physical and mental agility. His officers were blindly devoted to him and appeared uncritical of the course he gave them to pursue. 15. Actually there was much disagreement in the G.A.F. concerning the personality of SCHMID. His self-confidence was enormous and his enmity was feared. By virtue of his double office as Chef Ic and GOERING’s personal General Staff Officer, he exerted an influence over GOERING outweighing even that of JESCHONNEK when the latter was Chief of Staff. The strong tension later existing between SCHMID and JESCHONNEK was openly discussed. It was also accepted that SCHMID would not tolerate any officer about him who could become potentially dangerous to his position. 16. The composition of his staff certainly appeared to bear out this conviction. By dint bribery, a persuasive tongue and his proverbial conviviality - was a heavy drinker – he had created about himself a circle of officers who were completely under his thumb. 17. It is only in the light of this state of affairs that the discrepancies between the information from intelligence formations at the front and its dissemination by the Chef Ic to be discussed later in this series of reports can, to some extent, be understood. SOURCES OF INTELLIGENCES. 18. It was impossible for the 5th Abteilung to achieve the ideal solution for the collection of intelligence, namely, the subordination to it of all agencies concerned with the procuring of information. SCHMID’s suggestion to set up an inter-service department of O.K.W, which would build up a complete picture of the military, naval, and industrial potentialities of the enemy met with no more success. The result was that each service produced a partial appreciation from available sources, whilst the S.S. maintained a separate agent and foreign service. 19. The 5th Abteilung sought to administer its own press and attaché service, the technical study of foreign aircraft and the interrogation of prisoners. It also claimed that it should be the channel for liaison with the Foreign Office and the Ministry of Propaganda, should have the right to control sales of German aircraft abroad, and finally that it should have the sole responsibility for a day-to-day appreciation of the situation in war. From SCHMID's point of view, however, few of these matters were arranged satisfactorily. 20. In the spring of 1939 he was able to obtain control of the R.L.M. press department following upon certain blunders in the censorship, and in the few months remaining before the War introduced a tighter discipline. 21. The aims of the press department were to glean information from the foreign press as well as to conduct propaganda for the G.A.F. in press articles, pictures and films whilst maintaining a control of the security aspect and, after outbreak of War, to organise the G.A.F. press publicity units. The wartime organisation was never clearly defined, however, being complicated by the rival intervention of the Propaganda Ministry. 22. Liaison with the Propaganda Ministry produced good results only in the form of films and other comforts for the troops, but in the favourable periods of the War the difficulties of propaganda and censorship were not important. Later, however, WODARG found himself blamed by GOERING or the Chief of Staff for errors in publication over which it was impossible to keep a control – a situation which led to much personal friction. 23. The provision of foreign newspapers was in the hands of the Sicherheitsdienst and the supply of daily papers for intelligence purposes was therefore irregular, although periodicals could be obtained without much difficulty. Liaison with foreign scientific institutes was forbidden and could only be conducted through the Abwehr. 24. The G.A.F. Attaché Service abroad was subordinate to the Chef Ic, and was also responsible for securing the confidence of German-allied and neutral air attachés in Germany. Although the Attaché Service was regarded as a valuable potential source of information, its subordination to the 5th Abteilung was not brought about until the spring of 1939. 25. Its contribution to the information on foreign air forces was very small both in peace and war. Before 1939, when the Attaché Service had been subordinated to the central office at the R.L.M., its chief, Major CRAMON, had refused to regard the obtaining of information as part of his task, added to which GOERING's attitude had always been to send illqualified officers abroad as air attachés. 26. The importance attached by the head of Ic to the Attaché Service did not meet with official approval and the Attaché conferences held at Berlin at which was expressed the dissatisfaction of Bulgaria, Rumania, Hungary and Turkey with the lack of German support, were finally forbidden on account of their political character. 27. The Foreign Office declined to pass on military or air information via its officials, and only after outbreak of war was closer liaison effected by setting up a representative (Ic/Pol) who, however, only covered the rather restricted questions of violations of the frontier, exchange of prisoners, free passage of ships and listening to enemy radio. 28. Intelligence officers of all departments had at first been allowed to listen to the enemy radio, but this was restricted in summer 1942 to Ob.d.L. and the heads of the Luftflotten and a list had to be sent to the Propaganda Ministry of all persons to whom this authority was delegated. 29. SCHMID considered the Abwehr department to be the worst functioning institution of O.K.W. and stated that whatever material was supplied by it could not be appreciated at its true value because there was no way of judging the reliability of the agents. The Abwehr was a huge and expensive organization but, according to SCHMID, it was manned by the worst and most unsuitable officers in the services. It achieved very little in peace and only occasional chance results in war. At the beginning of the war it had undeserved larols thrust upon it by the attention paid in enemy countries to the fifth column. SCHMID did not find it surprising that the S.S. took over the whole organisation with apparent ease. 30. At the outbreak of war the special photo-reconnaissance Staffel formerly subordinated to the office of O.K.W. was put under the control of the 5th Abteilung and became the Ob.d.L. Gruppe. SCHMID praised the outstanding reconnaissance work of this unit in all theatres of war, as well as pioneer technical achievements in high altitude flying. The main sources of intelligence were, however, the wireless interception service and the interrogation of prisoners of war although the latter did not produce any outstanding results until towards the closing stages of SCHMID's period of office. 31. The wireless interception service was developed in peace-time by General MARTINI and was still controlled by him during the whole of the war. SCHMID recognised the valuable nature of the work done by this department, but depreciated the tendency of the Signals Staff to issue independent appreciations which were necessarily incomplete and unbalanced. In his opinion much more could have been achieved by its subordination to an organisation with a wider horizon and more penetrating aims. This deficiency became even more apparent to SCHMID when later in the war he became the Chief of Jagdkorps I and was concerned with defence of the Reich. 32. An appreciation by Generalleutnant SCHMID from memory, and unaided by documents, of Intelligence covered by the organisations mentioned above appears in Appendices III A to C of the present report. DISSEMINATION OF INTELLIGENCE 33. In the early stages of the war the 5th Abteilung was responsible for drawing up situation reports under the headings of air attacks, air defence and the sea and land situation. These reports were based upon those received twice daily from the fronts by the Ic Report Centre and often had to correct hasty and exaggerated reports which had reached GOERING through In (Operational channels). When Germany began to suffer reverses in the War the distribution of these Intelligence reports was restricted and in the spring of 1942 GOERING forbad their publication altogether. 34. Chef Ic had other tasks which were not purely concerned with the G.A.F. direction in that he passed Intelligence to interested specialist ministers and general staffs of German-allied countries whenever it seemed necessary or opportune, being thereby drawn into conferences outside the G.A.F. 35. At certain intervals reports were issued by Chef Ic containing a survey of the position on individual fronts. There were, however, other bodies which trespassed upon the functions of the 5th Abteilung or overlapped in the issue of intelligence appreciations. UDET's technical office under Oberst Ing. TSCHERSICH (GL/Rü) appeared to consider that its task was to prove that all foreign equipment was inferior to German. His reports on the excellence of German Intelligence, bombs, and weapons were preferred by GOERING, and enjoyed great popularity in the period after the French campaign. This organisation was finally linked up with the Chef Ic in 1940 and was reorganised with good effect under Oberst Ing. SCHWEPKE. 36. The head of the O.K.W. Wirtschaftsstab had announced at a conference in the summer of 1939 that his task in War would include the conduct of strategic air war-fare. This body did in fact issue reports on the sensitivity of foreign countries to air attack. A Ic Wirtschaftsstab was later formed under WODARG, but according to the staff of Oberstleutnant KILLINGER of Dulag Luft the opportunity of interrogation of Allied prisoners on industrial subjects was almost completely neglected; the interrogators could never obtain the necessary briefing or outside interest for such work. 37. An example of the worth of the Ic Wirtschaftsstab in January 1943 in the form of appreciation of British synthetic oil production and Russian oil production has recently come to light in a captured document now in the hands of A.D.I.(K) Document Section (List No.93). 38. In the opinions of KIENITZ, OHLETZ and ZETZSCHE the Ic Service itself suffered from the fact that its Chief did not present with sufficient obduracy a plain unvarnished picture of the situation which was to be concluded from practical experience at the front, and from indubitable facts photographic reconnaissance and captured material, underlined by P/Ws’ statements, outside intelligence and above all by evidence from the wireless interception service. 39. One result of this was that the total numbers of British bombers engaged in night attacks on Germany was not believed, and when the Chief of Ic confirmed the accuracy of CHURCHIL's figure for the 1000-bomber raid on Cologne in May 1942, he laid himself open to charges of defeatism and theorising. His reports acquired the reputation of "Lügenmeldungen" (lies) among members of the Operations Staff, and the Chief of Air Staff finally ordered that the Ic staff should be cut down to lessen the output of unpleasant nonsense. 40. In another instance of this kind, which is described more fully in the final report of this series, disagreement of Luftflotte 6's figures of Russian strength became so acute that JESCHONNEK ordered an enquiry into the methods of appreciation by Oberstleutnant OHLETZ, the Chief Intelligence Officer of the Luftflotte. 41. The strength postulated by Chief Ic for the Russian Air Force was but a fraction of the enemy strength actually encountered at the front and so increasingly worthless did the appreciations become that at the instance of von GREIM, OHLETZ refrained from handing them down to the operational units in order that their faith in the Higher Command should not be further shaken. There were days on which over 100 aircraft were shot down in the area of Luftflotte 6 alone, whilst Chef Ic was estimating the total Russian effort as 150 to 200 aircraft on the entire Eastern front. 42. In order to cover his intelligence officers, von GREIM himself flew immediately to headquarters to put the case personally. On his return he informed OHLEZ that JESCHONNEK had recognised the accuracy of the Luftflotte reports and wished the fact to be conveyed to him; he added that Oberst SCHMID would not remain in office much longer. DISMISSAL OF SCHMID 43. Matters were brought to a hold as far as SCHMID was concerned when in August 1942 an Ic officer of the Attaché Gruppe, Oberstleutnant SCHULZT-BOYSEF, was arrested by the Gestapo, in agreement with GOERING, on a charge of espionage for Russia. A number of other members of Ic were questioned and altogether at least 100 persons were arrested in Berlin in what became known as the "Rote Kapelle affair". 44. It was established that SCHULZT-BOYSEF, had had sources of information in the G.A.F. Technical Office, in the Foreign Office and the O.K.W. although he had not received secret information of any kind from Ic. Nevertheless, SCHMID was reproached by GOERING and the Chief of Staff for having protected SCHULZE-BOYSEF in 1938 and at the beginning of the war against the suspicions of the Gestapo. 45. In October 1942 SCHMID was relieved of his post, officially because of the Rote Kapelle affair; in the G.A.F., however, it was considered that his departure was due to events at the front not having conformed with his predictions. 46. After SCHMID, the task of taking up the reins of Ic was allotted to Oberstleutnant KOEGL who, however, was not suited to his duties and handed them over shortly afterwards to Major WODARG. KOEGL’s short tenure had one good effect in that it brought Oberstleutnant KIENITZ more into the picture. According to OHLUTZ that officer was a very accurate worker, but unfortunately, although undeniably the most valuable of the officers in responsible positions, did not possess the particular gifts necessary to make a successful Chef Ic. WODARG's TENURE OF OFFICE - 1942 to 1945 47. Major WODARG had been deputy head of Ic under Oberst SCHMID and he was also involved in the Rote Kapelle affair and was dismissed at the same time on a charge of failing to maintain adequate supervision. He was saved from further punishment only because it was maintained that meticulous secrecy had been carried so far in the Gruppe Ost and the Operations Staff that supervision by WODARG had been impossible. However, 5 months after the dismissal of SCHMID, WODARG succeeded KOEGL as Head of Ic. 48. He took up his duties with remarkable energy and he soon rid himself completely of the superannuated personal staff of Ic, apart from a small number of experts, and introduced young and highly ambitious General Staff officers. By this means he diffused considerably more energy into the department. Oberstleutnant KIENITZ was available to facilitate the smooth change-over from the SCHMID regime, and with his complete mastery of the methods of the past provided a good liaison with the new generation. 49. A table showing the Ic staff after its reorganisation by WODARG appears in Appendix IV and may be compared with the organisation under SCHMID given in Appendix II. 50. According to KIENITZ, WODARG undoubtedly brought the required ideas and breadth of vision to Intelligence. His methods of evaluating the War situation were completely revolutionary and his appreciations were built up on the basis of front Intelligence, being given out unvarnished and untainted by the methods which had played such a big part with his predecessor. For protection against attempts to oust him from the saddle he relied on a very close relationship with the ministry of Dr. GOEBBELS and the Reichssicherheits Hauptamt (security police headquarter). 51. His work was much hampered by his one outstanding peculiarity, which stamped his department with a certain character. His mind was imbued with a morbid distrust of the whole world and he suffered from a form of spy mania which could almost be described as pathological. This made life very unpleasant both for himself and for those about him. He had his officers watched continually and he checked every possible method and procedure with Amt IV of the Sicherheitsdienst in order to be in a position to cope immediately with any possible threat to himself or his department. 52. In his relations with GOERING Oberst WODARG was made to feel that he was an imperfect substitute for Oberst SCHMID the founder and architect of the Ic Service. WODARG never attended a Führer’s conference, nor was he allowed in HITLER’s presence because of his Jewish appearance - he had Jewish connections in both his own and his wife's family. In the O.K.L. he was the least important personality of the staff and he himself did not consider that he was the right man, especially in view of his ill health, to have played an active part in the shaping of policy and the raising of Ic from its subordinate role in the councils of O.K.L. 53. In spite of the drive which WODARG brought to Ic and in spite of his many ideas the work of Ic was doomed to failure in that it had to be performed at a time when the G.A.F. was at its lowest ebb, when through lack of air reconnaissance and liaison with Mi1itary Intelligence services, the enemy dispositions were becoming increasingly difficult to arrive at. Ides might burst from WODARG in an unfailing flow, but no sooner did some new factor crop up than the situation grew out of hand again. That the department functioned with any regularity at all WOGARD felt was due to Oberstleutnant KIENITZ, who as WODARG’s permanent deputy provided the one stable focal point in the entire organisation. INTERNAL INTRIGUE. 54. From the time of his own implication in the Russian spy affair, WOGARD maintained more or less friendly relations with officials of the S.D. in the Reichssicherheitsdienst Hauptamt, relations which were fostered by the judicious distribution of delicacies from G.A.F. stores. Apart from the confession that these occasional visits provided him with an excuse vis-à-vis the O.K.L. Staff for leisure hours in Berlin or otherwise unauthorised journeys, WODARG gave three examples of his exploitation of these contacts. 55. He passed on as a precaution any reports on officers who seemed to him to arouse suspicion, but often without any further action to be taken as the investigating authorities were too overburdened. In return the S.D. sometimes passed to Ic reports of corruption inside the G.A.F. which were dealt with internally by the O.K.L. without BORMANN being drawn into the matter. 56. After the bomb explosion in HITLER’s headquarter WODARG shortcircuited the S.D.'s investigations into the General Staffs by himself undertaking to watch over O.K.L. by means of GOERING’s Forschungsamt. This telephone eavesdropping was reduced to a farce since there was only one possibility of listening-in on six exchanges with a daily average of 12-18,000 telephone conversations. Discreet personal warnings were passed by WODARG to the Air Staff, and a few weeks later the control was dropped after WODARG had reported to GOERING and so to HIMMLER that the task had been carried out with negative result. 57. In autumn 1944 the Sicherheitsdienst office at Frankfurt charged Oberstleutnant KILLINGER and his interrogation officers with anglophile tendencies, defeatism and transgression of service rules. The S.S. demanded punishment of the offenders and subordination to the S.S. of the prisoner of war interrogation centre, which WODARG interpreted as a move by Amt IV of the R.S.H.A. to steal a march on Amt VI. WODARG claims the credit for having taken successful steps to get the matter settled by G.A.F. court martial instead of in the People’s Court. 58. Through his former activity as G.A.F. censor, he was on good relations with Dr. GOEBBELS, about whom he records the admittedly quite new point of view that he was personally in favour of coming to terms with the Allies long before the catastrophic effects of Allied air supremacy. He had a wholesome respect for Allied statesmen, and warned against the error of underestimating the enemy. WODARG used his contacts in the Propaganda Ministry, the personnel of which was mainly G.A.F. officers, to play off one government clique against another and to secure private information which he claims to have used to protect O.K.L. against the S.S. - until the latter took over all the key positions in the Propaganda Ministry. OBERSTLEUTNANT KIENITZ 59. In February 1945 Oberstleutnant KIENITZ was put in charge of Ic, although he was never appointed Chef Ic. After service as a Gruppenkommandeur with J.G.3 in the early part of the war he held office successively under SCHMID, KOEGL and WODARG, being responsible for Order of Battle first on the eastern front and later in the West. From November 1944 onwards he was WODARG's deputy and right hand man. 60. After taking over from WODARG, KIENITZ very soon came to the conclusion that the G.A.F. had become a purely ground support air force, and he therefore directed all his efforts towards the determination of Allied intentions first in the East, later in the West — as indicated by the position of new airfields, ammunition and fuel dumps, unit movements, etc. For this information he relied mainly on the W/T listening service; the results of his findings he embodied in as air situation report. GERMAN INTELLIGENCE – CONCLUSIONS. 61. The mentality of the German rulers, who had risen to power in internal political strife and were fanatical to the point of despising the intelligence of the so-called "Intellektuellen", was such that they were incapable of appreciating an intelligence service of their own fashioning or of respecting the intelligence service of the enemy. Otherwise according to WODARG, they would have avoided the War in the first place, or having recognised the absolute superiority of the enemy, would have concluded peace earlier - about the beginning of 1942. 62. The General Staff of the G.A.F., in common with the other branches of the armed forces, was in WODARG's opinion too small and untrained to assume effective leadership even if the Chief of Staff had recognised the value of the intelligence service in general or appreciated its work in detail. Since this recognition was lacking, Ic was inadequately staffed in comparison with Ia, the operations department. Moreover, the lack of co-ordination between the sources of information and Ic limited considerably the latter's ability to draw up a complete intelligence picture. 63. The activity of the General Staff and particularly the Ic department was further crippled by HIMMLER's assumption of power over the State and armed forces, and from spring 1944 onwards the General Staff had to struggle for existence against the encroachments of the S.S. 64. Hauptmann ZETZSCHE has summed up the main weaknesses of German Intelligence during the War in the following main points:- A) Within the State. i) There was no hard and fast Ic organisation within the Wehrmacht with boundaries clearly demarcated from those of similar civil bodies. ii) Wehrmachtführungsstab Ic did not co-ordinate the work of the Heeres-, Marine- and Luftwaffenführungsstäbe Ic, but was merely a distributing agency for the Ic reports of the individual Wehrmacht components, exercising practically no authority over them. iii) The large number of intelligence organisations in Germany without clearly defined tasks, including O.K.W./ Amtsgr.Ausland, R.S.H.A. (Mil.Amt), R.S.H.A. (Hauptamt IV) and Reichsministerium Speer (1. Abtlg). (The Propaganda Ministry and the Foreign Office also partly covered the same territory). iv) The lack of a Ministry of Economic Warfare. Military Commands were obliged to cope with the problems without expert knowledge or guidance, (e.g. in the Battle of Britain). With so many independent intelligence organisations and no centrally co-ordinated hand the Germans consequently never saw the enemy picture as a whole. B) Within the G.A.F. i) Again innumerable bodies working over the same ground as G.A.F. Ops. Staff Ic, TLR Rü, Gen. Nafü, Waffengeneräle, Forschungsamt, etc. These departments were not responsible to Ic and on grounds of personal ambition worked by and far for themselves. All this was due to the lack of a “man of stature” as chef Ic (GOERING’s phrase). ii) The not altogether happy organisation of G.A.F. Ops. Staff Ic (Luftwesen, Ic/See, Ic/Bild). iii) The subordination of Ic to Chief of G.A.F., whose decisions were too often swayed by In considerations. iv) Ic was kept as ill-informed on the subject of German weapons, apparatus, etc. that it was incapable of offering suggestions which would otherwise undoubtedly have arisen from Ic knowledge of Allied material. v) Ic's tactical suggestions were mainly ignored owing to the jealousy of the Training Abteilung which again was in no position to evaluate enemy information since in the sphere of training too, there were many figures in the pie (principally those of the Waffengeneräle and Forward Commands). vi) Ic was unable to have its wishes carried out by Forward Commands. It could not order but only request. vii) The poor quality of Ic personnel. Many officers who were not wanted by other branches of the service found their way into the various departments of Ic. viii) Ic was considerably understaffed. Moreover, such staff as it had was unevenly distributed in relation to the tasks. ix) There were no Ic officers with the flying units, so that valuable lessons which might have been drawn from battle experience were lost. x) The lack of intelligence courses for officers xi) The insufficient support of Ic in every sphere, e.g. no aircraft, no cars, no money or additional comforts and drinks (the latter for P/W interrogation centre, Oberursel), insufficient communications with Oberursel. 65. Ironically, the sole organisation to recognise the worth of Ic was the S.S. (since most personnel had connections with foreign countries and were therefor already under suspicion). Hence the efforts of the S.S. (by means of agents) to keep a watch on the entire Ic organisation in Germany and finally even to take it over. A.D.I.(K) and Walter A. Frank U.S. Air Interrogation. for:- S.D. Felkin Group Captain." |
Fighter defence of germany: Control of fighters
"SECRET A.D.I.(K) Report No.525/1944
THE FOLLOWING INFORMATION HAS BEEN OBTAINED FROM P/W AS THE STATEMENTS HAVE NOT AS YET BEEN VERIFIED, NO MENTION OF THEM SHOULD BE MADE IN INTELLIGENCE SUMMARIES OF COMMANDS OR LOWER FORMATIONS, NOR SHOULD THEY BE ACCEPTED UNTIL COMMENTED ON AIR MINISTRY INTELLIGENCE SUMMARIES OR SPECIAL COMMUNICATIONS. FIGHTER DEFENCE OF GERMANY CONTROL OF FIGHTERS BY THE "Y" PROCEDURE. 1. The Interrogation of G.A.F. fighter pilots in the past has made it possible to form a picture of German tactics against U.S.A.A.F. bomber formations from the point of view of fighter interception force. Knowledge by P/W of the raid tracking organisation on the ground, however, has up to the present been lacking, and many gaps have remained in the picture, particularly where the Fühlungshalter (shadowing aircraft) and the "Y" controlled fighters are concerned. 2. Two G.A.F. Signals Officers, who had been directly concerned with "Y" control sites - one man was a plotting officer - have now described in some detail the method of ground control at present being used in the operation of fighter interception forces and of the shadowing aircraft; their knowledge was chiefly confined to methods practised in France, but they state that the same principles also apply to operations in Germany. 3. Some of the information is of a semi-technical nature, and the present report is therefore divided into two parts; the first part concerns the operational aspect of fighter control, and the second part deals with the equipment and method of operation of the unit of control - the "Y" site. I. CONTROL OF FIGHTER INTERCEPTION. OPERATIONAL CONTROL. 4. In Allied attacks on Germany, the Jagd Division receives and plots all Radar information on the movements of the bomber formations, together with direct reports from the Fühlungshalter aircraft shadowing those formations and the plotting reports from the fighter "Y" control sites. It is primarily on this information that the Divisional commentary and the control of a whole interception action are based. 5. The sole medium for transmission of the Divisional commentary is the "Y" site; the latter is connected by landline to the Divisional plotting centre so that the plotting of an operation is carried out at both those centres simultaneously. 6. An interception can therefore be directed either from Divisional Headquarters or from the "Y" site, but it is normally the plotting officer at the "Y" site who puts out the R/T commentary. 7. The area of control ("Führungsraum") of a "Y" site is limited by the range of the transmitters used, and according to P/W the average range may be taken as 250 to 300 kilometres; the Division therefore controls an operation over its territory by making use of a chain of "Y" sites. 8. The area of R/T control of a "Y" site may be increased by additional ground relay transmitters, known as "Brummer", so that R/T communications with fighters can be continued outside normal range. These stations and their operation are discussed in Part II of this report. 9. The present P/W stated that the Central Operational Headquarters ("Zentral Gefechtsstand"), situated in the Berlin area, receives simultaneous information from each Divisional plotting centre and makes its own plots on that basis; the fighter commentary on the "Reichsjägerwelle" or such orders as are put out on the broadcaster "Annemarie" emanate from that centre, but according to the present P/W are only utilised by fighter interception forces in case of failure of the Divisional commentary, or the breaking up of an interception formation. "Y" CONTROL OF FIGHTERS. General Principls. 10. The principles of "Y" fighter control, whereby the range and bearing of friendly fighter are determined by a "Y" ground station, are already well known. 11. In operations in Germany, the "Y" site, known as a "Stellung", usually consists of five separate stations ("Stationen"), each of which comprises a transmitter hut and mast, and a receiver pylon incorporating a D/F, and rangemeasuring unit. All five stations are connected to a plotting room situated on the site. 12. Each station of the site is allotted a separate W/T channel, known as "Linie", consisting of a transmitter and a receiver carrier frequency; thus a number of individual aircraft can be controlled simultaneously within a given area. 13. In order to extend the control of a single aircraft, such as a night-fighter, to that of a number of aircraft, such as a day fighter interception force, it is only necessary to include a "Y" controlled aircraft amongst the fighters of the formation. 14. In this case the receivers of all aircraft in the formation wi11 be tuned to the ground transmitter frequency to receive R/T instructions from the plotting centre as well as from the fighter formation leader. 15. In this manner up to five separate interception formations can be controlled, each on a different frequency form a single "Y" site. If necessary, all five formations can be brought together to intercept a single bomber formation, or alternatively, each of the five formations can be despatched separately to meet the bombers or their fighter cover at various points. 16. The ground transmitter carrier frequencies, known as the "Gemeinschaftswelle", are distributed over the 40.4 to 42.3 mc/s. band at intervals of .05 mc/s. and the ground receiver carrier frequencies, known as the "Messwelle", are distributed over the 38.5 to 40.4 mc/s. band at the same intervals. A list of such frequencies numbered 1 to 40, appeared in a recently captured Signals Order (A.D.I.(K) 4.68/1944, paras.41-42). 17. In operation, the ground transmitter carrier frequency is modulated by a continuous note of 300 or 3,000 cycles; the receiver/transmitter in the "Y" aircraft (known in J.G.3 as the "Lotse" aircraft) receives its modulation and automatically re-transmits it on another frequency in the 38.4 to 40.4 mc/s. band; the aircraft transmitter frequency is normally 1.9 mc/s. lower than the ground transmitter frequency. 18. The re-transmission from the aircraft is picked up at the "Y" station by the D/F receiver, by which the bearing of the aircraft is than determined. The same transmission is also received by the range-measuring unit, and the distance of the aircraft from the station is determined by measuring the phase difference of the modulation received. 19. The height of the aircraft under control is not measured by the "Y" station, but is obtained over the R/T channel from readings taken in the aircraft, thus all the data required for the plotting of a controlled aircraft, viz. bearing, distance and height, are obtained. 20. There are two methods of controlling aircraft formations by means of the "Y" procedure, and these are illustrated diagrammatically in Sketch I. 21. The first method, known as the "Begleiter", has now dropped out of use, but is repeated here as a matter of interest. By this method, the leading aircraft of a formation, known as the "Führer" aircraft, also acted as the "Y" aircraft, whilst the accompanying aircraft of the formation were known as "Begleiter". 22. In the Führer aircraft the receiver was linked with the transmitter and the receiver frequency was tuned to the ground transmitter frequency, whilst the aircraft transmitter was set to the frequency of the ground receiver. 23. In all other aircraft of the formation the receiver was tuned to the transmitter frequency of the leader, and in none of them was the receiver linked to the transmitter. The formation was thus plotted solely by the position of the Führer aircraft. 24. The Begleiter method has, according to P/W, now been replaced by a newer method known as the "Gemeinschaftswelle", in which the receivers of all aircraft of a fighter formation, including that of the leader, are set to the ground transmitter frequency ("Gemeinschaftswelle"). In this method the aircraft is not the leader of the formation but he flies as N°2 to the leader, with one or more similar aircraft as reserves. 25. Upon referring to the Sketch, it will be seen that the formation leader's instructions are not heard directly by the "Y" station; they are picked up by the receiver of the "Y" aircraft (in this case on 41 mc/s.) and automatically retransmitted (on 39.1 mc/s.) to the ground station. 26. On the other hand, should the pilot of the "Y" aircraft wish to speak to his own formation leader, he must pass his message to the ground station on 39.1, mc/s., and the plotting officer will repeat the message on the Gemeinschaftswelle. Transmission of Commentary. 27. A plotting officer on the "Y" site, or his counterpart on the extended line to the Divisions, is provided with headphones connected to the receiver of the range-measuring unit, and with a microphone which is connected to the transmitter. 28. By depressing a key he can link the microphone with the ground transmitter and can impose R/T speech on the already modulated carrier frequency which it sends out. It is not necessary to discontinue the modulating note, so that D/F’ing and range measuring can therefore proceed at the same time as the commentary. 29. In practice, the fighter interception force is led by the "Y" control officer as far as within sight of the bomber formation, at which point R/T control ceases to allow the formation leader to direct the combat, and is only taken up after combat when the fighters have re-formed for a second interception, and the "Y" aircraft has made fresh contact with ground control. During this time, however, the ground station continues to plot the formation through the "Y" aircraft. Fühlungshalter Aircraft. 30. It will be remembered that when a U.S. bomber force is reported to be entering German territory a special shadowing aircraft, the Fühlungshalter, wi11 be sent to meet and follow that force and report its movements and position. 31. The Fühlungshalter aircraft operates under the control of the "Y" plotting officer in the manner described above. In the opening stages of an operation, the Fühlungshalter is directed to the penetrating formation on the basis of Radar plots, and upon making contacts it takes up a position usually above and to the rear of the enemy formation. 32. The Fühlungshalter then reports strength, type of formation, direction, height and fighter cover of the penetrating force. After the initial report, further information is only sent in the event of major changes in the composition or movements of the U.S. formations. 33. As soon as the Fühlungshalter has made contact with the bomber formation, all R/T control by the "Y" site ceases; the Fühlungshalter aircraft communicates directly with Divisional Headquarters through the receiver of the "Y" station and the "Y" control officer stands by and listens to the R/T traffic whilst maintaining a plotting control by the "Y" procedure. 31. According to P/W, the Divisional Plotting Centre at this stage relies on Radar data for following the formations, and only depends upon the Fühlungshalter aircraft to supply immediate details of such circumstances as withdrawal of fighter cover. II. "Y" CONTROL SITE, AND IT’S OPERATION. "Y" CONTROL SITE. Manning. 35. A "Y" control station requires nine men per shift, or 27/30 men per 24 hour, for its operation and a site consisting of nine stations is normally occupied by a company of 150/160 operators and 50/60 maintenance personnel. The personnel of the "Y" control station is distributed as follows: Transmitter hut: One operator. D/F Cabin: D/F Operator and log-book keeper. Range-Measuring Cabin: A Supervisor, range-measurer and log-book keeper. Plotting Room: Plotter (friendly plots), plotter (enemy-plots) and plotting officer. Communications. 36. Internal: The standard layout of the internal system of commutations in a "Y" site is shown diagramatically in Sketch II. In this Sketch "Station A" shows the general layout applicable to all five stations, while "Station B" shows a diagram of the internal communications which are in reality repeated in all five stations. 37. The internal lines which are shown in the Sketch have the following names and functions: (a) Plotting line (Werteleitung): A telephone connecting the log-book keeper in the D/F cabin to the range-measuring cabin and "Y" plotting room for transmission of bearing readings. (R in Sketch). (b) Telephone (Ringleitung): Connects the D/F cabin, the range measuring room and the transmitter hut for the passing of internal instructions. (I in Sketch). (c) Modulation line (Modulationsleitung): Connects the range-measuring unit to the transmitter for carrying the modulation note. (M in Sketch). (d) Diode line (Diodenleitung): Connects the rangmeasuring room to the transmitter hut; required only when a Siemens range-measuring unit is used. (D in Sketch). (e) Receiving line (Hörleitung): Open line which connects the receiver and the range-measuring unit to the control desk in the plotting room; a parallel line also runs to the Division. (H in Sketch). (f) Transmitter Circuit (Besprechungsleitung): Open line which connects the Division and the plotting room to the range-measuring unit. This can be used as a closed line for internal speech or as an open line for transmission of R/T instructions to the aircraft from the Division or the "Y" plotting officer. (B in Sketch). (g) Keying circuit (Tastleitung): Open line which connects the Division and the "Y" plotting officer to the range-measuring unit and transmitter. Depression of a key at Divisional Headquarters or on the "Y" plotting officer's control desk operates relays to the transmitter and modulation line of the range-measuring unit, allowing R/T instructions from the Division to be transmitted on the carrier wave to the aircraft under control. (K in Sketch). 38. According to P/W, the twenty Channels connecting the five stations of the site to the Division may be carried on two single lines utilising a multi-channel carrier frequency equipment. 39. External W/T Channels: The number of external W/T channels varies, depending on the location of the control site, but usually consists of the following:- (a) Command network star (Befehlsstern d. Ln. Regt.) for reception of tactical orders and general administrative business from and to the headquarters of the Ln. Regt. to which the company operating the "Y" site belongs - a Saram or FuGe.3 set is used for this traffic. (b) Divisional signals star (Divisionsbefehlsstern), used for operational orders and transmissions of range values in the event of failure of the ground lines to the Division. This traffic is also usually conducted on Saram or FuGe.3 sets. (c) Aircraft reporting frequency (Frontflugmeldewelle, or more recently Gerätemeldewelle). On this channel W/T transmissions are received from all Radar search sites giving briefly the important data relating to aircraft activity taking place within the area of the site. This transmission takes place by day and night and supplements and confirms information on enemy activity received from the Divisional Headquarters; messages are written out and handed to the "Y" plotting officer. A pack type W/T set is used for reception of this traffic. Brummer Relay Stations. 40. According to P/W, Brummer relay stations are placed throughout German territory and are employed for relaying R/T speech in cases where aircraft have flown beyond the normal R/T range of the "Y" site. 41. The Brummer stations are connected to the Division H.Q. by landline and are controlled by the Division; should a "Y" plotting officer find that an aircraft under his control is nearing the limit of R/T range, he will request the Division H.Q., to connect with a Brummer station in the relevant area. 42. Whilst making this request, the "Y" plotting officer states the frequency on which the "Y" station is operating, and the Brummer will transmit at that frequency. According to P/W, the R/T traffic on Brummer stations is usually confined to directional and homing instructions, although "Y" control can sometimes continue after the limit of R/T range of the "Y" site has been reached. Plotting Hut and Operational Procedure. 43. The plotting rooms of the five stations belonging to "Y" sites are grouped, in a single hut known as the "Auswertung" (plotting centre). According to P/W there are two types of hut at present in use and a plan view of both these types is shown in Sketch III. 44. The older type of hut contains a separate plotting room and table for each of the five stations, but this type of control contra is said to have offered no satisfactory method of centralised supervision of plots and each plotter had to act on his own responsibility. 45. The improved type of plotting hut has been developed by the Flugmeldedienst (aircraft reporting service) and is believed by P/W now to be widely in use in Germany. In this type of hut a series of six tables is arranged on one side of a rectangular room and each table is fitted with the normal control point and is occupied by an M.C.O. plotter. The chief plotting officer's table and control point are placed behind the row of tables in such a position that he has a view of all proceedings. 46. The reason, for the six plotting tables is that on some "Y" sites the "Egon" method of fighter control is practised in addition to the normal "Y" control and an extra plotting table is set aside for this purpose. 47. According to P/W the Seeburg table has been withdrawn from the majority of "Y" sites in favour of the present simple method of plotting. In front of each group of three tables is a vertical glass screen marked with the German fighter grid and the main outlines of a 1:300,000 map of the area of control. 48. Behind each screen are four plotters, three of whom receive and plot friendly bearing and range values on the reverse side of the glass screen. Plots are compiled from range and bearing data in the range-measuring room of each station and are passed through to these plotters in terms of the fighter grid; the fourth plotter is responsible for receiving and marking enemy plots. 49. All plots are numbered and in addition the courses drawn on the glass screens during each operation are copied on to a sheet of paper for record and reference purposes. 50. The extremely close and continuous contact with the "Y" controlled aircraft enables the plotting control officer immediately to detect any deviation of the aircraft from the correct course and to rectify the error by ordering a slight correction of course when necessary. 51. The plotting officer bases his instructions to the controlled aircraft on the estimated position of the friendly and enemy aircraft; in doing this an allowance is made for a delay varying from five to ten seconds between the times of the observations of enemy aircraft when originally made and when finally received and plotted. By experience, specific allowances are made for the extent of the delay from the various stations supplying enemy plots. 52. When the fighters are nearing the limit of the range of the "Y" site, the "Y" plotting officer is responsible for handing the aircraft over to the next station; he must advise that station, through Divisional Headquarters of the receiver and transmitter frequencies in use, since the new station may have been operating on other frequency channels. This step is taken sufficiently early to allow the new station taking over control to tune in on the R/T traffic of the controlling station. 53. The "Y" plotting officer's task ceases for the time being when the control aircraft or accompanying formation is brought in sight of the enemy or, in the case of night-fighters, when the aircraft is sufficiently close to its target to be able to make an attack with the aid of search equipment. 54. Plotting by the "Y" station continues throughout the sortie and combat of a fighter interception force, and does not cease until the aircraft return to base after combat. A.D.I.(K) S.D. Felkin 23 Sept.’44. Wing Commander" |
German early warning Ground Radar
"SECRET A. D. I. (K) Report No. 390/1945
THE FOLLOWING INFORMATION HAS BEEN OBTAINED FROM P/W AS THE STATEMENTS HAVE NOT AS YET BEEN VERIFIED, NO MENTION OF THEM SHOULD BE MADE IN INTELLIGENCE SUMMARIES OF COMMANDS OR LOWER FORMATIONS, NOR SHOULD THEY BE ACCEPTED UNTIL COMMENTED ON AIR MINISTRY INTELLIGENCE SUMMARIES OR SPECIAL COMMUNICATIONS. RADIO AND RADAR EQUIPMENT IN THE LUFTWAFFE – X. German early warning Ground Radar. 1. This report is the tenth of the series dealing with radio and radar equipment in the Luftwaffe. As in the case of the previous nine reports (A.D.I.(K) 343, 357, 362, 365, 369, 370 and 330/1945), it is based on interrogation of General Nachrichtenführer MARTINI, Director General of Signals, and some members of his staff, and has been supported by a number of relevant documents of recent date which were in the possession of the General's Chief of Staff. DEVELOPMENT OF EARLY-WARNING RADAR. Early History. 2. As recounted in A.D.I.(K) 343/1945 and again mentioned in A.D.I.(K) 365/1945, the Freya, which became the first standard early-warning radar set for the G.A.F., was developed by the firm of Gema, Berlin, with the encouragement of the Navy. The first Freyas were in operation as naval coast watchers in 1938 at a time when the G.A.F. was only thinking of radar in terms of searchlights and Flak. 3. The Technisches Amt wished to push 50 cm. wavelength like that of Würzburg, but the Navy backed the longer wavelength of Freya, and General MARTINI, who immediately appreciated the advantage of a wide-angle apparatus of Freya type to early warning, asked that a number of Freyas should be allocated to the G.A.F. 4. In early 1939 one of the present P/W, Oberst Ing. HENTZ was selected from among the Köthen staff to take charge of the first experimental Freya used by the G.A.F. in that year. It was thought at first that the Freya would only give indications over the sea, but during the march on Prague in the first part of 1939 an experimental Freya was set up in the Riesen Gebirge in order to watch Czech aircraft which might react to the German advance. This experiment was not a success, as the signals operators had not been expecting to find their tube cluttered up with permanent echoes. 5. At the outbreak of war the G.A.F. possessed eight Freya stations distributed round the East and North Frisian islands guarding the Heligoland Bight and the approaches to the North Sea ports. These Freyas proved their value during the early Bomber Command raids on Cuxhaven and Wilhelmshaven etc., when some outstanding successes were registered by German fighters, which were vectored on to the bomber formation as a result of the early-warning obtained by the Freyas. It was this success which convinced the G.A.F. of the practicability of radar as an early-warning device. Early Developments. 6. The range of the early Freya was of the order of 80 km and their accuracy of the order of a few degrees. No height finding facilities were available. The height finding problem at close range was solved by directing a Würzburg on to the target when it came within the range of the latter, which in these days was about 30 km. This system of height measurement continued to be the only practical one for a long period, although the field operators had put in requirements for height finding Freya apparatus as early as 1940. 7. Experiments by the G.A.F. produced the Wassermann, but the German Navy experimented with the object of introducing height finding facilities in the Freyas, and the N.V.K. at Pelzerhaken produced the "Chinese" and "Tiefland". The former gave maximum location by means of a compensator in an serial system inclined at 45° and was used for angles greater than 15°, whilst the latter was intended for angles less than 15°. The combination of the two mounted on the Freya was known as the “Malaya”. 8. Measurement of height with the Tiefland was possible between 2° and about 15° over level terrain; measurement of angles of less than 5° was, however, very inaccurate and range was actually less than that of the Würzburg-Riese. Over uneven terrain, measurement of the vertical angle was impossible. 9. The Tiefland had the disadvantage of being complicated in operation - a large field of reflector nets was also necessary - in addition to which it gave no better performance than the Würzburg-Riese. Its use would only have been justified had it been a device which could be moved easily and quickly and had there not been restrictions on the selection of suitable sites for its mounting. 10. Freya Fahrstuhl was designed by Köthen as early as 1943 but was never put into large-scale production, and was not satisfactory. This apparatus depended on the difference of phase observed between direct ray and ground reflection to give height. 11. Finally, in 1944 methods or swinging the beam electrically were used in the Wassermann for height measurement, but the Würzburg remained the basic means of measuring the elevation up to the end of the war. The D/F accuracy of the Freya was greatly improved when the split beam or A.N. technique was introduced in 1942, end this made Freya valuable for fighter control on the Egon system. 12. The range of Freya, naturally dependent on height of an objective, was about 150 km. but this was not considered sufficient for the early-warning service and efforts were made in 1942 to produce early-warning apparatus with greater range. The first of these was the Wassermann which improved the early-warning range to about 200-250 km, while the Mammut, used by the Navy for coast watcher purposes, was also used by the G.A.F. and gave ranges up to about 300 km. Finally Elefant, which gave ranges up to 350 km., was built and came into operation in about 1944. 13. By the middle of 1943 an elaborate early-warning service covering the whole of Germany and composed of sites with both Freyas, Würzburgs and Giant Würzburgs had been built up, and a number of Wassermann chimneys were in operation along the coast of Europe. 14. The great improvement in D/F accuracy resulting from the split beam technique was utilised by KAMMHUBER to develop his box system of night fighting, and in fact at this time it was strictly forbidden for a night fighter to fly any form of night defence other than the close control of the KAMMHUBER box system. 15. Other methods of fighter control namely the Egon and Bonito, were under development, and of these the former also used the Freya wavelength for range and D/F. Effect of first use of Window. 16. When Window was first used in July 1943 the whole of the early-warning system as well as the night fighter control system broke down completely. 17. The first German reaction to the use of Window was to attempt to filter it out or obtain some method of distinguishing between blips due to window and those due to the aircraft itself. Virtually no work had been done on this problem before July 1943 because GOERING had been so frightened by the prospect of Window being used by the enemy that the theoretical possibilities had been hushed up and scientists has not being allowed to work on the problem (cf. A.D.I.(K) 334/1945). 13. Nevertheless, when Window was first used by the Allies, it was only a matter of some ten days before the first solution to the Window problem for the Würzburg was forthcoming in the shape of the Würzlaus, which relied on the Doppler effect. High priority was given to the problem and even money prizes were offered for solutions. 19. Three main types of equipment were evolved as a result of the various solutions proposed; one was Taunus, which gave greater blip resolution, another was the propeller modulation type such as Nürnberg and the third was based on the Doppler effect, the latter being termed Laus A—J devices. Of these the Freyalaus for Freya and Wasserfloh for the Wassermann were not used operationally till 1944. Effect of Further Countermeasures. 20. As Allied countermeasures became more intense and electronic jamming was also used, the signals staff decided that it should be the genera1 policy to provide all types of radar with the facility for a change of frequency. The first efforts to do this were brought about by mechanical trombone tuning of the aerials so that two or three neighbouring wavelengths could be used. This was termed the WISMAR principle. 21. Sometime in 1943 Dr. SCHULTER of the firm Siemens developed the Breitband (wide band) aerial which enabled a much greater frequency spread to be used. This principle was termed Voll Wismar and with increasing experience was to be applied to all types of ground radar. At the same time Freya and Würzburg were allotted different "Inseln" or frequency bands in the hope that some of these bands would not be jammed locally. This policy was carried to great lengths, but Allied countermeasures still remained extremely effective. 22. Either owing to the weakness of German centimetre technique, or to a lack of appreciation of the value of centimetre wavelengths, the main trend in avoiding British countermeasures was towards longer wavelengths, and special Köthen Freyas using wavelengths of 5 and 8 metres were prepared. When jamming on the more normal wavelengths became severe these reserve sets were operated for a minimum period often only a few seconds, in order not to compromise the wavelength, and an effort was made to obtain a clear picture of the air situation with their aid. 23. Eventually wavelengths up to 13 metres came into use for early-warning with giant sets such as Elefant. British Transmissions as an Aid to Early Warning. 24. Despite all these precautions, and despite the fact that P/W claimed that many of these wavelengths were not effectively jammed, it frequently happened that the earlywarning service was unable to obtain a clear picture of the situation and recourse had to be made to indirect means. The monitoring service was of particular value in this respect, and they successfully maintained their point of view that it was not worthwhile jamming the fighter R/T because D/F’ing of this provided excellent early warning. 25. The fact that British night bomber crews were in the habit of using Monica and H2S from the very beginning of their flights was also of great assistance in supplementing the early-warning picture. In the same way Allied I.F.F. was of great value, and special Freyas known as Freya Flamme which covered the I.F.F. frequency band were erected on some important early-warning sites. 26. Finally, an ingenious system which was invented by Oberst Postrat SCHOLZ called Klein Heidelberg utilised the reflection of the transmissions from British C.H. stations and was regarded as virtually unjammable. Development of Panoramic Presentation. 27. As early as 1940 a requirement was put up for a panoramic presentation for early-warning radar, but no great progress seems to have been made until the discovery that H2S was using a P.P.I. successfully. Difficulties were encountered with the early types such as Propeller developed by Lorenz and it was not until early 1944 that the Jagdschloss sets came into existence. These were originally used entirely for early warning and not with the idea that night-fighter aircraft could be controlled with their aid. It was not until 1945, when the value of Jagdschloss was fully appreciated and it was numerous enough to cover 1st class radar sites throughout Germany that some efforts were made in its employment for control of night fighters. 28. With the intended introduction of Neuling I.F.F., which could distinguish not only between friend and foe but between individual crews as described in A.D.I.(K) 365/1945, fighter control from panoramic presentation was to be greatly extended. SPECIAL PROBLEMS AND APPLICATIONS ON GROUND RADAR. Day Fighter Control. 29. The necessity for day-fighter control from ground radar stations was early appreciated by the Signals staff, and the Battle of Britain proved to them how successfully it could be used by air force inferior in numbers. Spasmodic attempts were made to introduce it into the G.A.F. but the German fighter tradition was too strong, and the pilots would not accept ground control. 30. It was not until 1943 that close ground control on the Egon system using the FuGe 25A in the aircraft was introduced. Control of Night Fighters. 31. With KAMMHUBER’s box system two Würzburg sets were used - one to follow the target and one to follow the fighter, the positions of each being projected on to the map by means of the so-called Seeburg Tisch. So long as there was no jamming of ground radar, this method was successful and could place a fighter within 200-400 metres of the target. Later the Würzburg Riese was used and the majority of these sets were allocated for this purpose. 32. A suggestion had been made that the Würzburg 50 cm. transmission should be used simultaneously for giving the fighter his vectors and a system named Sprechstange was experimented with. It was rapidly found that, if the operator failed to hold the fighter in the beam, the pilot received no instructions from the ground, and so vital instructions might not be heard. For this reason it was soon abandoned as not practicable. I.F.F. Problems. 33. The FuGe 25A was originally designed by the firm of Gema for use with the first Freyas operating on 2.4 metres. As recounted in A.D.I.(K). 365/1945 it became the standard German airborne I.F.F. set in 1942 and was used with the Kuh transmitter and Gemse receiver on all ground radar installations, whatever the wavelength, with the exception of the Würzburg series. A full description of the problems of ground radar has been given in the above-mentioned report. Plotting of High Flying Aircraft. 34. In 1944 it was found that the very high level Mosquito bomber attacks on the Reich sometimes crossed the coast unplotted, and at best were only detected intermittently after passing the coastal screen of Wassermanns which could swing their beams upward electrically. The reason for this was that the main lobs of Freya only went up to about 8,000 metres. There were two subsidiary lobes, the higher of which reached to 12,000 metres, but the latter only gave limited coverage at this height over an estimated range of 70 km. 35. The Würzburg beam was too narrow and did not give general coverage, while Freya Fahrstuhl, which could also be utilised for aircraft flying at great height, had hardly been introduced into operations. For this reason considerable use was made of the Würzburg Riese-G which was a Giant Würzburg with a very narrow 50 cm. beam, with additional Freya aerials on 2 metres, set in the paraboloid, giving a wide beam coverage as well. As the circle paraboloid could be tilted upwards, excellent high coverage was obtained and high fliers were plotted with its aid. Plotting of Low-Flying Aircraft. 36. The Germans were fully aware of lack of low cover, which enabled aircraft flying low over the sea to cross the coast unnoticed. A number of experiments were conducted to overcome this disadvantage by placing special aerial arrays at considerable height above the ground as for instance in the case of the Würzmann using the Würzburg frequency and the Tiefentwiel using the Hohentwiel A.S.V. frequency. 37. Some experiments were also conducted with wavelengths of about 20 metres with the idea, it was believed, of making use of the curved path which those waves followed. The experiments were never completed, as this band was interfered with by communications signals transmitted on the same wavelength. 38. Experiments had also been made at Köthen with Taunus equipment coupled to the Freya to obtain extremely high resolution. A Fieseler Storch aircraft was used, flying at 150 metres over flat country, and under these conditions the aircraft could just be seen at ranges of 4 or 5 km. through the ground returns due to woods and houses. It was concluded, however, that this range was so small that no advantage was to be gained. GROUND RADAR INSTALLATIONS. Freya. 39. Freya was manufactured by the firm of Gema, Berlin, which, at the outbreak of war, was only a small establishment largely financed by the Navy. Members of the Technisches Amt, as well as of MARTINI’s staff, criticised the firm, severely, saying that they lacked experience of manufacturing and were unwilling to make themselves adaptable. They described the Freya Stand for instance as a “cast iron monstrosity”, which they felt could easily have been made very much lighter in weight and manufactured more simply. 40. Despite this complaint against Gema, it was a principle that all ground radar apparatus should be of fairly simple construction so that it could be made mobile. A few days after the invasion of Norway the Germans were experiencing considerable trouble from bomber raids in the Stavanger area and an urgent request was sent out from there for a Freya to be supplied. This job was given to one of the present P/W, and within three days of receiving it a Freya LZ Stand had been dismantled and packed into three Ju.52's and transported to Stavanger. Eight days after the reception of the order the Freya was operating. 41. At the beginning of the war the G.A.F. possessed eight Freyas. At the end of the war over 1,200 had been manufactured and a document dated 1st January 1945 states that 671 were in operation at that time. 42. Owing to the incidence of all forms of Allied jamming, the original wavelength of 2.40 metres had been modified very considerably. The following impressive list of wavelengths current at the beginning of November 1944 was found among documents brought by General MERTINI’s staff:- M. M. Insel A Insel B Insel C Insel D Band Z - 2,32-2,45 - 2,08-2,24 - 3,00-3,30 - 1,50-1,55 Köthenband gelb/braun Köthenband gelb/rot Köthenband Ludwig Köthenband gelb 1,70 1,80 1,95 2,00 Y X W V U T Vollwismar Bereich I II III - 1,55-1,60 - 1,60-1,65 - 1,65-1,70 - 1,70-1,75 - 1,75-1,80 - 1,80-1,85 - 1,90-2,50 - 1,20-1,90 - 2,50-4,00 Köthenband gelb/grün Köthenband grün Köthenband rot Köthenband braun Köthenband weiss Köthenband schwarz Köthenband blau Köthenband violett Köthenband grau Köthenband blau neu 2,56 3,15 3,40 3,65 4,05 4,60 4,80 5,20 5,75 8,80 43. In addition to this formidable list P/W states that in early 1945 experiments were being made with a Köthen Freya on about 12 metres. The Köthen Freya with wavelengths of over 4 metres presented a problem to the aerial experts which was being solved by using Yagi aerials mounted above the normal aerial mattress. Although it was considered desirable to mount the aerials at a height above the ground of at least ten times the wavelength, this was not always possible; for instance the Yagi aerial of Köthen Blau (4.80 metres) was, according to a document, to be mounted 30 metres above the ground. 44. Two further new wavelengths known as the Rotschwarz and Grünschwarz were planned and were to operate on two of the frequencies used by British Gee in the hope that they would not be jammed. It was realized that these wavelengths could only be used when the jamming of Gee by Heinrich transmitters was not being carried out. The Freyas so equipped were to be located as far as possible from the positions of the Heinrich jamming transmitters. 45. In order that these longer wavelengths should not be compromised, a so-called Kurz Zeit apparatus was built into the Freyas which allowed transmission of only ten impulses and prevented more impulses being emitted for a period which could be set between 2 and 22 seconds. It was considered unlikely that listening aircraft would be able to tune to these short interrupted pulses. 46. A document, dated June 1944, in the possession of a member of General MARTINI's staff, contains a short history of the jamming experienced by Freya. Extracts from this document are given below in free translation: "Jamming by Jamming Transmitters. "In April 1942 the jamming of Freya on the original 2.40 metre wavelength was reported. "On 5th March 1942 the Chef N.V.W. put up a requirement to the Technisches Amt asking that alternative frequencies for Freya should be made available, basing his request on the fact that parts of a Würzburg, from which the exact wavelength could be determined, had fallen into enemy hands during the Cap d'Antifer (Bruneval) raid on 27th February 1942. By the end of 1942 the original Freya wavelength was being jammed generally. "As no steps to provide alternative frequencies in operations had at that time been taken by the Technisches Amt or by industry, Ln. Versuchs Regiment Köthen was asked to use its resources to provide them. "After about one month, on 15th June 1945, the first Freya which operated in an unjammed band, the Köthen Grün, was handed over to a unit for operational use. "In 1942, Freya on Insel B and Insel C had been demanded from the industry but they were not delivered until 1943. The Insel B sets were first available on 23rd February 1943, but shortly after being used operationally were jammed by the Allies. The Insel C apparatus was made available on 10th July 1943 and has been in regular production until the last few months. "It must be recorded at this point that the first new Insel was produced by the industry about a year after Köthen had produced an improvised apparatus. Moreover, the Technisches Amt and industry were unable to give the Signals branch a Freya which was not jammed. Assistance had to be sought from Köthen, who produced Köthen bands which alone enabled the further operation of Freyas to take place. "In view of the jamming situation the Chef N.V.W. demanded on 19/12/42:- (a) Freya frequencies below 1.90 metres. (b) A Voll Wismar band which allowed constant frequency change (c) Long waves over 4 metres, with the suggestion that the Yagi aerial arrays should be used. "The following comments must be made on the foregoing demands:- (d) The first Freya below 1.90 metres (Flum 41) became available on 2/7/43. (e) The first Voll Wismar was delivered in May 1943, but in spite of this the first mass-produced apparatus was not available until July 1944, and then only in small numbers. (f) The problem of long-wave Freyas was never taken up by either the Technisches Amt or by industry. This problem was solved by the development by Köthen of Yagi aerials, and these were first built into operational sets in September 1944. "Jamming by Window. "The possibilities of jamming by Window were made quite clear on 17/3/1943 and a requirement for an anti-jamming device for all radar apparatus was formulated. Not until 19th June 1944, that is, one year and three months later, was the Freyalaus, which had been developed by ZVH, made available by the Chef TLR. "Since it was clear that a change-over to longer waves to avoid Window was the only possibility available at that time, the only solution was the use of long-wave apparatus (Yagi Köthen Grau). With this type of equipment it has been possible for some months to obtain an early picture free from jamming. Further Yagi wavelengths were developed and units are being equipped with them. "To make recognition of new radar wavelengths impossible for the enemy, a short transmission system (Kurz Zeit Messung) described above was formulated as a requirement on 23/9/42. At the data of writing this has not yet been introduced." 48. The decision to avoid Window by using longer wavelengths appears to have been taken on the results of some experimental work. When Window 1.80 metres long was produced against SN2, Insel C was severely affected, and research work was done on the susceptibility of different wavelengths to Window of this length. The diagram produced in Appendix I shows the effect produced by a standard quantity of 1.80 metre Window at a range of about 70 km. on various types of Freya. 49. As a result of this experimental work, the Signals staff realised that it was an advantage to increase the wavelengths as the intensity of the signal received fell off sharply above 3.80 metres. It was considered impracticable to put a longer Window into use and as a result the so-called-Köthen bands were produced. 50. The Germans were unaware that we were dropping very long Window {rope) at a later date. A certain number of specimens of this had been picked up and it had been assumed that it had something to do with meteorological observations. 51. In an interesting publication Funkmessnachrichten No. 19 dated 25th February 1945, it is stated that the C-Insel of Freya suffered worst from jamming by ground transmitters but gelb-rot, grün, braun, weiss and grau Köthen bands and the A, B and D Insel were also jammed at times. 52. Airborne transmitters were beginning to jam the Köthen grau band, while Köthen braun and D Insel experienced occasional interference by airborne-electronic jammers. Only on one occasion had jamming of the Köthen weiss been observed from the air. 53. The G.A.F. was vitally interested in the Köthen grau band which was the main stand-by for the early-warning service, and it was this band and the Köthen blau on 8.80 metres about which instructions had been given that they were to be switched on only for very short time in emergency. About 40 Köthen grau equipments were in operation. 54. The range claimed for Freya was 80-120 km., with a range accuracy of ±300 metres and D/F accuracy with split beam (A.N.) 1/3°. 55. It is stated in the same document that by February 1945 all Freya equipments, with the exception of some motorised units, had been fitted with the Freyalaus. A new type of A-J device, which is however, not described, named the Prüflaus was at this time being tested on a few sites. Freya Flamme. 56. A certain number of Freyas in the Insel D band were set aside for the purpose of triggering off British I.F.F. when this had been left on in aircraft inadvertently. It was claimed that, provided the aircraft was flying at a considerable height, ranges of up to 450 km. had been obtained with the Freya Flamme. D/F was difficult due to the wide spacing of the short pulses and no continuous echo beingobtained. The Germans were aware that six codes were transmitted by British I.F.F. and believed that they know the significance of the various identifications. 57. Initially this proved a most useful very long-range early warning, but the number of aircraft flying with I.F.F. had been greatly reduced during the last year of the war. Freya Fahrstuhl. 58. The Freya Fahrstuhl, designed by Köthen, is a Freya with height—finding facilities obtained by making use of the reflected ground wave. It was first introduced in early 1943, but owing to unknown causes, a certain amount of trouble was experienced and only about eight equipments were in operation on 1st January 1945. The original requirements were formulated in 1940 for a Freya type apparatus to give elevation. 59. This set had a range of 220 km. and was used for height finding by the early—warning service and also as an aid to Flak if the Würzburg were jammed. The wavelength used was 2.00 metres (Köthen gelb). The Freya Fahrstuhl was originally intended as an early-warning radar giving height, but the few produced were largely used to give height to Flak when the latter's Würzburg was jammed. Würzburg. 60. The history of the development of this apparatus will be told more fully in the next and final report of this series which will deal with German Flak radar, for which purpose it was originally designed. 61. The original Würzburg Insel A had no split beam D/F but was nevertheless used for early attempts to control night fighters. 62. The frequency used by Würzburg A was a single spot frequency, between 53.0 and 54.2 cm. It was first introduced in any quantity for raid reporting purposes in the autumn of 1940, when it was used to obtain the height of aircraft observed on the Freya. Its maximum range was about 25 km. 63. The next type introduced was the Würzburg C with A.N. D/F facilities and range of 25 km. The first Würzburg C’s came into service in the summer of 1941. A few were used for controlling night fighters, but the great majority was used by Flak. The Würzburg C’s were on fixed frequencies in the band 53.0 to 54.2 cm. 64. The final form of Würzburg, the D, had still only a 25 km. range operationally, but was a general improvement over the C with split D/F facilities giving an accuracy of ± ½° and range accuracy of ±50 metres. It was introduced in the autumn of 1941 believed to have been used for Flak purposes only. 65. The original sets were in the frequency band known as Insel A 53.0 - 54.2 cm but later a B band from 56.7 to 58.0 and a C band from 62.3 to 63.8 were introduced. 66. Finally a Würzburg was manufactured with wide band aerials using the Urechse equipment which allowed any wavelength between 53.0 and 63.8 cm. to be used. The Urechse transmitter was being generally introduced in the spring of 1945. Würzburg Riese. 67. The Würzburg Riese was introduced in 1941, and from the beginning was mainly used for the close control of night fighters on the Himmelbett system. In all, 452 sets were in operation on 1st January 1945. A few sets were used for providing the Gross Batterien, situated at Berlin and other places, with information for their anti-aircraft operations, but these were of the Riese G (Gustav) type with Freya aerials incorporated in the paraboloid, so that a 50° wide search beam was provided as well as the 13° main beam on 50 cm. 68. The wavelength used for the Freya section of the Riese G was originally 2.20 Metres, but wavelengths of 1.80 metres and 1.70 metres were also introduced, and it was intended to use 1.60 metres in the future. The Würzburg section of the Riese used the A and B Insel of the Würzburg bands, namely 53.0 - 54.2 cm. and 56.7 - 58.0 cm. The range of the Würzburg Riese was about 70 km. and its range accuracy was of the order of ±50 metres. 69. Some ten of the sets used for Flak were provided with Voll Wismar using the Schwarz Echse transmitter on a new wavelength of 1.50 metres. 70. The additional Freya wavelength was found to be particularly valuable against U.S. day bombers, which usually only jammed the Würzburg 50-60 cm. band and left the Freya band unjammed. Wassermann. 71. The original purpose for which Wassermann was introduced was to obtain a more powerful early warning radar with a greater range than Freya, and it was therefore the G.A.F. equivalent of the novel Mammut. Three main types of Wassermann were produced, the L, S and M. 72. The Wassermann L (Leicht = light) was produced by Gema and was said to have a range of 200 km., an accuracy in D/F of ± ½° and in range of ±5 km. The first set came into use about the summer of 1942; two types were manufactured, namely L.I, on 2.40 metres and L.II on 2.01-2.27 metres, in which spot frequencies (Streuwellen) at 15 mc/s intervals were available. About 25 of these were built. They were constructed as lightly as possible so that they would be transportable, which was considered specially important for the Balkans and in Norway. It was estimated that they took about 3-4 weeks to erect. They had, however, a disadvantage that in strong winds the whole tower was apt to be blown over. 73. The Wassermann S (Schwer = heavy) was also constructed by Gema and its accuracy was comparable with the L, except that ranges of 300 km. were obtained. The first equipment was erected towards the end of 1942 and in all some ten became operational. The first seven sets erected (S.1 to S.7) used wavelengths of 2.40 or 2.46 metres. These numbered S.8 to 10 used 2.36 metres, 2.34 metres and 2.29 metres. These sets took something over 4 months to build, but they were at least more robust than the Wassermann L. 74. The final form of Wassermann, the M. (Mittel = intermediate) was designed by Siemens. Its accuracy in D/F and range was about the same as the other two types but a maximum range of about 220 km. was obtained. 75. The first types introduced were the M.I and M.II in the autumn of 1943. Both used frequencies in the 2.01-2.20 metre band but the M.II allowed different frequencies within this band to be used on the Wismar principle. 76. The M.III used the 1.20-1.90 metre band, and was of the wide band Voll Wismar type but only two sets were built, as it was succeeded in the spring of 1944 by the M.IV which gave wide-band facilities from 1.90-2.50 metres. Some twelve M.IV. were in operational use by January 1945, and more were being produced. 77. The latest form of Wassermann was to be the M.V. which was a wide band equipment working on 2.50-4 metres, of which one experimental set had been set up on the Baltic coast. 78. Since about the beginning of 1944 an electrical compensating arrangement had been built into the Wassermann which allowed the beam to be swung in elevation, and an elevation of about 15° could be obtained. The A-J device Wasserfloh with Doppler effect was fitted first towards the end of 1944. 79. Generally speaking the Wassermann was a disappointment. Production of Elefant was postponed as the original estimate of Wassermann's range, as late as autumn 1943, was that it would give 400 km. coverage. Wassermann never succeeded in giving coverage much over 200 km. Mammut. 80. This coastal radar equipment which was known to the Allies as the "Hoarding" was really a Naval coast-watching radar of which some 8-10 specimens were operated by the Luftwaffe. It had the advantage that the polar lobe was well beamed - more beamed than the Wassermann - and, therefore, it was not very susceptible to jamming but it took about 8 months to erect and was costly and unvieldy. The comparatively narrow lobe scanned electrically by means of a phase shifter, termed a compensator. The wavelength used was the original Freya band 2.40 metres and the range achieved some 300 km. No height finding was available. Elefant. 81. The Elefant, sometimes referred to as See-Elefant was produced by the Reichspost and was designed in part by Ober Postrat Dr. SCHOLZ. At the end of the war three equipments of this type had been built and a further three were in course of erection. The wavelength used was comparatively long, in conformity with policy of escaping the effect of Window by increasing the wavelength. Of the three sets built, two were in the 7.90-8.80 metres band, and the remaining one in the band from 10.70-12 metres. 82. A D/F accuracy of 1° was obtained and range accuracy of ±4 km. The first set was created in the summer of 1942. But it underwent constant improvement and its form was not finalised until 1944. In November 1943 the Technisches Amt refused definitely to sanction the large-scale introduction of Elefant as although a range of 400 km. was obtained similar results were expected (but never obtained) from the Wassermann. A few were, however, built by Köthen in the field. 83. In order to prevent the long wavelength from being compromised, the Elefant was only used for short periods and when the air situation was not clear to the ear1y-warning service. This was the more important as it was realised that Elefant could easily be jammed. The normal array consisted of two 100 metres high towers. Heidelberg. 84. One of the present P/W believed that experiments were being carried out with an early warning set on a wavelength of between 18 and 20 metres which was to be called Heidelberg. He understands that jamming interference was encountered, as the set operated on the frequency band used by W/T traffic, and for this reason the project was dropped. P/W stated that it was hoped to obtain very great ranges, as the waves would conform to the earth's curvature. There may, however, be some confusion in his mind with the Klein Heidelberg system described below. Klein Heidelberg. 85. The name Klein Heidelberg was given to a system utilising reflections from aircraft of the pulses emitted by British radar stations or by distant German stations. Strictly speaking, therefore, it was not a radar set at all. 86. The results obtained were satisfactory at the three stations used, but at the time of its invention by Ober Postrat SCHOLZ, in 1941, it was not regarded as of particular importance, as their radar was not being jammed. 87. In 1944, when jamming became serious, the Klein Heidelberg system proved of great value. Its D/F was poor but range was adequate for early warning information. 88. It was noticed in October 1944 that our 25 cycle CH stations had started to change their p.r.f. but a radio locking system was improvised within six weeks and thereafter no trouble was experienced. Tests were made to utilise the Gee pulse sources, but the system worked adequately with CH and the experiments were not pursued. 89. When he was interrogated on this matter Dr. SCHOLZ stated that he understood that the results obtained at the Römö station were surprisingly good, despite the great distance from Great Britain. Würzmann. 90. The Würzmann was the name given to an experimental coastal set which was to be used for the location of low flying aircraft. According to P/W, it was a Jagdschloss Michael B aerial array set up on end. The aerial array of the Jagdschloss Michael B consisted of a double row of 18 Würzburg mirrors and measures not less than 56 metres x 7 metres. 91. This gigantic erection was mounted so that the electric centre of gravity was 50 metres above sea level and produced, in fact, a Würzburg beam which was very narrow in azimuth. With its aid it was claimed that aircraft flying at 0 feet could be seen at a range of 20 km. Tiefentwiel. 92. Tiefentwiel was the code name applied to an aerial array placed high above ground using the Hohentwiel A.S.V. set with the intention of detecting low-flying aircraft coming in over the sea. No details of the aerial array or method of operation were known but it was stated that the Tiefentwiel achieved as good results as the Würzmann, namely a range of about 30 km. Hohentwiel Boden. 93. Funkmessnachrichten publication No. 19 announced the introduction of a short-range highly-mobile early-warning radar called Hohentwiel Boden which could be erected in 15 minutes. The set consisted essentially of the Hohentwiel A.S.V. set with an aerial array mounted on the top of a 10' high mast. This improvisation was carried out by the Ln. Versuchs Regiment Köthen, who stated that individual targets could be seen at a range of 30-35 km. and formations at 60-70 km. It was to be used in the front line to give advance warning of raids. PANORAMIC RADARS. Propeller. 94. Some time in 1943 the firm of Lorenz produced an idea for a P.P.I. presentation for early warning to which they gave the code name "Propeller". This set relied on extremely rapid rotation of the aerials and used a wavelength of about 50 cm. 95. Just before the set was officially demonstrated to the G.A.F. it exploded. All the apparatus was lost and the project was abandoned. Jagdschloss F. 96. The first type of early-warning radar set giving panoramic display which come into operation in usually referred to as the Jagdschloss, although it’s official designation is Jagdschloss F, to distinguish it from later types, such as the Michael B and Z. It was produced by the firm of Siemens and was first used in operations in early 1944. About 65 Jagdschloss F equipments had been manufactured by the end of the war. 97. Equipments No. 1 to 62 were of the Voll Wismar type using wide band aerials and covering the band 1.90-2.20 metres. From 63 onwards the frequency band to be covered was 1.20-1.90 metres. A document mentions Jagdschloss lang (=long) with a wavelength of 8.0-10 metres. No information about this has been obtained. 98. These sets were used exclusively by the early-warning service and gave a range of about 100 km. with a D/F accuracy of 1° and a range accuracy of 4.5 km. 99. The range accuracy depended largely on the presentation on the 40 cm. P.P.I. tube. At 100 km. the area of error was stated to be 5 x 5 km. but Köthen was attempting to improve the presentation so that blips could be read to a greater accuracy by introducing electrical range rings. 100. Another trouble that was being experienced in February 1945 was that the 50 cycle frequency at the national electric grid affected the presentation so that the blips which should have appeared as small arcs actually appeared as an arc with a wavy out-line. 101. The P.P.I. tubes produced by Siemens were being modified to avoid this imperfection while the Fernseh A.G., who also produced tubes for Jagdschloss, were working on the problem. It was believed that a new type of "Tonfrequenz" cable would be necessary. Particular attention was being paid to this point because of the difficulties in reading the tube caused by window. 102. According to a document a new type of valve called the Nullode was being introduced at this period to replace the 8D.6 diode in the Simultan unit. 103. It was proposed to introduce a selecting switch, by means of which three alternative pictures could be produced on the P.P.I. tube. The first picture showed all blips present on the tube, the second position allowed the I.F.F. to be switched in, while the third was a purely I.F.F. picture in which only friendly aircraft with I.F.F. operating came up. 104. The I.F.F. problem had not been fully solved and it is stated in a document that a separate FuGe control set is necessary to assist in obtaining unequivocal identifications. 105. In this same document mention is made of the Münchhausen system which was to use coloured photographic films to distinguish between Windows and moving targets; stationery targets would appear on the film as dark spots while moving aircraft would appear as spots with red and blue edges in the direction of movement. This system had been worked out at Werneuchen and in February 1945 the first apparatus was in use with a Jagdschloss equipment in the field. The film, however, took between one and two minutes to develop. 106. Further difficulties in the form of dead zones were being encountered with Jagdschloss and it is suggested in Funkmessnachrichten publication No. 19 that a wire netting surface with a radius of 50-60 metres should be built round the Jagdschloss in order to get rid of the lower dead zone and to aid in increasing the range against high flying aircraft. It is stated that one ton of iron wire netting necessary for each site. 107. According to P/W the electrical jamming of Jagdschloss was never very severe, particularly as it had Voll Wismar. The fact that it was causing trouble was, however, proved by the fact that in Funkmessnachrichten publication No. 19 it is stated that a number of special cameras had been provided and were in use at various Jagdschloss sites to take pictures of the type of jamming encountered in order to ascertain what measures could be undertaken against jamming. 108. A so-called electric lens was to be used as a means of seeing through Window. This was an arrangement whereby a magnification of between 2 and 3 times natural size could be obtained of a circular area of the picture. The area which could be magnified could be chosen but was limited to circles whose circumference passed through the centre of the tube, but did not reach the edge of the 40 cm. P.P.I. tube. Jagdschloss Michael B. 109. A ponderous aerial array of two rows of eighteen Würzburg mirrors measuring 56 metres long x 7 metres high was used in the Würzmann experimental early-warning radar, and formed the serial array for Jagdschloss Michael B with the array in a horizontal position. The wavelength employed, was that of a Voll Wismar 53.0-63.8 cm. 110. By means of this aerial a beam of ½° horizontal width was obtained and a range of about as much as 250 km on single aircraft was expected. It was also expected that the narrowbeaming of Michael B would be of great assistance in avoiding Window. The dead zones were to be overcome by switching the frequency to another wavelength in the Voll Wismar band II, which was believed to run from 50-60 cm. The first set was to be ready in April 1945. Forsthaus F. 111. This apparatus was designed by Telefunken to fulfil the same purpose as the Jagdschloss Michael B using the so-called Euklid 25-29 cm. waveband employed by the Navy. Once more a very long aerial array 48 metres long and about 8 metres high was used, employing a cylindrical paraboloid. A wave guide antenna (Hohlraumstrahler) was placed along the focal line with a second and a third wave guide parallel to it above and below respectively. The object of these two supplementary wave guide aerials was to provide displaced beams and so avoid the dead zones. A range of 220 km. was expected against single aircraft but no details were available as to whether it had come into operational use. Forsthaus KF. 112. In order to introduce as rapidly as possible a panoramic early-warning radar in the West on a hitherto unused wavelength, a smaller form of the Forsthaus F called the KF was to be introduced while the F was being completed. It was planned so that it could be used on a railway wagon; the revolving aerial array was only 24 metres long and it was expected to give a range of 120 km. The wavelength and electrical circuits used were exactly the same as in the Forsthaus F. Dreh Freya. 113. This set, which was also known as Freya Panorama, was first introduced in June 1944. It consisted of a Freya aerial of the Breitband type working in Bereich I (1.90-2.50), the frequency of which could be adjusted at will. The aerial was so built that it rotated through 360° and gave a remote panoramic presentation. About 20 equipments were in use in January 1945. The range claimed for it was only about 100 km. Jagdhütte. 114. This apparatus, which was produced by Siemens, gave a panoramic P.P.I. display of the German I.F.F. responses, using 24 metre or 36 metre rotating aerials. The wavelength employed was 2.40 metres and it was planned, with its aid, to trigger off the FuGe 25A. In this way friendly fighters were to be controlled from the ground at ranges up to about 300 km. It was fully realised that if the FuGe 25A frequency was ever jammed the Jagdhütte would be useless, but it was not considered likely that the Allies would attempt to jam it. 115. On the 1st January 1945 the first Jagdhütte equipment was being erected, and it was expected that production would amount to two per month thereafter. At the end of the war about 8-10 were being built, but there is no information as to how successfully they were employed. Jagdwagen. 116. Jagdwagen was designed as a mobile Panoramic radar to control fighterAs at close ranges immediately behind the front. It was a project of the firm of Lorenz. The aerials were considerably smaller than the Jagdhütte, the array being only 8 metres long. The aerial array was to be mounted on the Kumbach stand as used in the Egerland Flak set. The frequency bend used was that of the A.S.V. set Hohentwiel namely 53-59 cm. 117. The horizontal beaming was of the same order as that in the full Jagdschloss F, namely about 6°, and ranges claimed for it were of the order of 40-60 km. for medium heights. A small P.P.I. tube of about 15 cm. diameter was used. 118. In February 1945 the first sets were being tried out at Werneuchen but it was hoped to produce the Jagdwagen, in series, as a fully mobile panoramic set operated by a motorised company to install them on aerodromes so that a picture of the local air position could easily be obtained. Jagdschloss Z. 114. The Jagdschloss Z was the centimetric form of Jagdschloss, which was in development by Siemens; the rotating aerials were to be about 24 metres long. These sets were to give an extremely narrow beam and so offer protection against jamming. The range expected was of the order of 100 km., and although the first experimental equipment had been built it was not expected that sets would came into operational use until the autumn of 1945. Forsthaus Z. 120. The Forsthaus Z was another form of 9 cm. panoramic for early warning, which was produced by the firm of Telefunken. It differed from Jagdschloss Z mainly in the design of aerials and was about in the same stage of production. No information could be given as to the advantages or disadvantage possessed by Jagdschloss Z. NOTE: One of the documents brought to England by General MARTINI’s staff contained a list of the frequency coverages mentioned in this report, and is reproduced in Appendix II." |
German Radio Countermeasures
"SECRET A. D. I. (K) Report No. 380/1945
THE FOLLOWING INFORMATION HAS BEEN OBTAINED FROM P/W AS THE STATEMENTS HAVE NOT AS YET BEEN VERIFIED, NO MENTION OF THEM SHOULD BE MADE IN INTELLIGENCE SUMMARIES OF COMMANDS OR LOWER FORMATIONS, NOR SHOULD THEY BE ACCEPTED UNTIL COMMENTED ON AIR MINISTRY INTELLIGENCE SUMMARIES OR SPECIAL COMMUNICATIONS. RADIO AND RADAR EQUIPMENT IN THE LUFTWAFFE – IX. German Radio Countermeasures. 1. This report is the ninth of the series dealing with radio and radar equipment in the Luftwaffe. The present information was mainly obtained from Dr. Ingenieur SCHOLZ, a civilian employee of the Reichspost Zentrale who was in charge of a sub-section of Abteilung 6 of the Generalnachrichtenführer dealing with the problem of RCM (radio countermeasures). 2. Interrogation of this man has been supported by information gained from other members of General MARTINI's staff and by a number of relevant documents of recent date in possession of the General's Chief of Staff. Some useful additional help was given by two engineers who had recently been engaged in testing ground and airborne jamming equipment at the G.A.F. research establishment at Werneuchen. 3. The radio countermeasures used by the Germans have been treated in this report under four headings, the first being a brief historical account of their employment, and the other three dealing in turn with RCM against communications, metric radar and centimetre radar. The types of jamming transmitters referred to by name, or of which a mention has been found in documents, are listed in alphabetical order and their functions briefly described in Appendix I to this report. THE GERMAN MONITORING SERVICE AND EVOLUTION OF COUNTERMEASURES. BASIS FOR COUNTERMEASURES. 4. At the beginning of the war the G.A.F. High Command was not radio minded; GOERING in particular has been frequently accused by his underlings of paying no attention to technical matters. In the opinion of General MARTINI's staff, the vital importance of radio warfare and radio countermeasures was only truly appreciated by the General Staff towards the end of 1944. Those responsible for German jamming, therefore, had great difficulty in obtaining permission to use the countermeasures to the extent that they could have wished. 5. The countermeasure organisation relied in the first place on the German "Y" service, which formed Abteilung 3 of General MARTINI's staff, to give advance information of new radio activities, and for this purpose it employed a staff of expert radio engineers whose task was to identify and explain any new frequencies or types of transmissions received. If, however, novel features in a monitored transmission were observed and could not be explained, a commission for the investigation of the particular subject was set up. This commission was composed of representatives of the "Y" service and of the Development (E) departments of the R.L.M., representatives of the research (F) department of the R.L.M., and such experts from the leading firms as had special experience in the field of radio which was thought to be in question. 6. Evidence collected by listening, though it could be very valuable as intelligence, did not necessarily tell the whole story or indicate the most suitable form of countermeasures. As far as airborne equipment was concerned, statements made by prisoners of war often helped to fill out the details and the capture of equipment and its identification with the new transmission was of great value, even if the equipment was severely damaged. 7. Intelligence information from the above three sources could usually be pieced together to tell the whole story, so that decisions could be taken as to whether radio countermeasures were required. 8. The Germans relied very largely on the laboratories and experience of the Reichspost Zentrale (RPZ) to solve the technical problem of how and with what equipment to jam, and they obtained for the duration of the war the loan of an engineer of that organisation (the present P/W) who was put in charge of RCM and carried out liaison with RPZ to this end. EVOLUTION OF COUNTERMEASURES. 9. The decision to jam a particular type of transmission rested very largely with General MARTINI and was often taken despite the protests of the "Y" service section of his staff, who were interested professionally in monitoring all transmissions. Particularly in the case of R/T, the "Y" service insisted that more strategic and tactical information could be obtained by D/F’ing enemy transmissions than any tactical advantage which might be gained by jamming them. 10. As an instance of the extent to which the decision lay with General MARTINI the following case was quoted: In 1942 Allied night fighters were becoming a nuisance in the Mediterranean area but General KESSELRING had to ask General MARTINI’s permission to jam their ground-to-air R/T control in his theatre of operations and only then could the countermeasures be undertaken. 11. The first German radio countermeasures were instituted in September 1940 during the day bombing raids of the Battle of Britain and were directed against British radar operations in the Channel. The first and most important site used was that at Mont Couple behind Calais were, by the end of the war, a battery of some 35 jammers had been set up. 12. Radio countermeasures against Gee were put in hand in the summer of 1942 and at about this same time the first attempts were made to jam A.S.V. in the Channel. From this time on, the countermeasure warfare increased and consideration was given to jamming all types of new radar devices. 13. In about 1943 it was realised that countermeasures might well be called for on every wavelength, and Dr. SCHOLZ put up a requirement to the Reichspost Zentrale (RPZ) laboratories for a series of jammers to be designed for covering all wavelengths from 50 cm. upwards. These jamming transmitters were designed in the Potsdam RPZ laboratories, and improvements were constantly being incorporated in them so that if there was a sudden call for countermeasures on an as yet unused frequency, a practical design was available and apparatus could be built at short notice. 14. As a result of this policy new countermeasures could be put in hands quickly, but in practice they usually took considerably longer to organise than might theoretically be expected because the ground crews had to be trained in their use. Dr. SCHOLZ stated that with a few exceptions these ground crews were of second-rate material and it was frequently a matter of weeks before they were sufficiently well-trained for the countermeasures to become effective. COUNTERMEASURES AGAINST COMMUNICATIONS. GROUND-TO-GROUND COMMUNICATIONS. 15. With the possible exception of communications between land and convoys, P/W believed that no attempt was made to jam Allied W/T communications on the ground. Listening to them was considered to be of the greatest strategic intelligence value and little or no tactical object was served by jamming. 16. Radio countermeasures against the B.B.C. news service were in the hands of civilian authorities, and the G.A.F. had nothing whatsoever to do with them. Dr. MEINEL of the Reichspost was believed to have been responsible for the production of the type of jamming modulation which was generally used. GROUND-TO-AIR R/T. 17. The question of jamming Allied ground-to-air and air-toair R/T was one of the points most strongly disputed between the "Y"-service and the operational side of the G.A.F. The "Y"-service maintained that by listening to and D/F’ing traffic, both strategic and tactical intelligence was obtained and that it was frequently their best source of early warning of attack by aircraft; as a result relatively few attempts were made to jam Allied R/T. 18. In the case of German raids on England the signals staff agreed that there was an advantage in jamming British R/T communications; this point arose when the possibilities of Mark IV A.I. were first realised early in 1941. The question of how to undertake countermeasures against British A.I. was discussed and the weak point of the system was held to be the R/T link from ground to air, because it appeared to be essential for the night fighter to be brought within 2 km. of the bomber before contact could be made. 19. The Reichspost Zentrale built an airborne R/T jammer set which was given the name of Karuso and was intended to prevent R/T being heard by the night fighter when the latter was within 3 km of its target. Within eight weeks the first Karuso equipment was ready and a total of 100 were built. With the cessation of the bombing of England in about May 1941, the majority arrived too late and Karuso was only used once in a limited number of aircraft in a bombing operation when, P/W believed, Plymouth was the target. 20. When in 1943 trouble with British night fighters was again being experienced in the Mediterranean, the Karuso sets were sent down to that theatre. There, however, the range of British A.I. was found to be about 4 km. instead of 2 km., so that the power output of Karuso had to be boosted to give it a range of 5 km. 21. The method employed was barrage jamming using two bands (100 - 110 mc/s and 110 - 120 mc/s) with mechanical condensertuned sweep through the band. There was not room for two transmitters in one aircraft so only half the band could be covered in any one German bomber. Karuso III, a later improvement, was to be capable of being tuned through 100 - 150 mc/s band but so far as is known, it was not put into use. 22. Subsequent tests of Karuso indicated that it had insufficient range, and by December 1944 the Starnberg, which was developed in 1940 by D.V.L. as a jammer against radar, had also been tried out but was likewise considered inefficient. A new set named Nervtöter was under development but never came into operational use. 23. It was decided that the jamming of R/T would be of value against air activity when the invasion took place and prior to D-Day some 50 or 60 modified Karl II jammers had been formed into a Stördorf (= jamming village) and assembled at a site on the Channel coast near Dieppe. With this assembly of jammers, all possible frequencies in the 100 - 150 mc/s R/T band could be covered. 24. A few days before the invasion the site was carpet bombed by the Americans and although the jammers had been somewhat dispersed, 90 of them had their aerials damaged or were put out of action. There was some delay in bringing up reserve motorised units and the invasion took place before they reached the Channel coast. As a result, no countermeasures against fighter R/T took place during the invasion. 25. In November 1944 a limited amount of jamming of fighter R/T in the 70 - 100 mc/s band was carried out on the western front by motorised units and from a few fixed sites. These countermeasures were on a restricted scale, owing to lack of apparatus, but it was hoped to interfere with Allied ground control of fighters and fighter R/T. AIR-TO-AIR R/T. 26. During defensive operations over the Reich against Allied aircraft, countermeasures were very rarely used owing to the insistence of the "Y"-service on the value of D/F’ing transmissions, particularly as the German early warning radar was heavily jammed. Early in 1945, however, it was planned to create four jamming villages (Stördorf) each with ten Karl transmitters in order to jam R/T during raids over German territory. The use of airborne jammers to carry out the same task had been considered but it was felt that airborne jamming was less rational than jamming from ground stations because the frequencies had to be constantly monitored. 27. By the end of the war a new jamming transmitter called the Feuerland had been developed by Blaupunkt. This allowed noise modulation to be used in addition to the more generally used Reichspost modulation. A few sets were sent up to the Holstein area just before the capitulation, but it was believed that they had never been used in operations. 28. The standard type of modulation which had been developed by Reichspost consisted of a number of "Kipp" frequencies - sharp triangular pulses produced by blocking oscillators - superimposed on the carrier wave. Tests of its effectiveness at audio frequencies were carried out early in the war and a statistical analysis of them seemed to show that it was the most effective modulation against R/T. RUSSIAN R/T 29. The airborne FuGe.10 was being developed for use as a jamming transmitter against the 3 - 6 mc/s band R/T used by the Russian Air Force. This apparatus never came into operational use. R.C.M. AGAINST METRIC RADAR EARLY WARNING RADAR 30. It was in August or September 1940 during the Battle of Britain that the first German countermeasures were directed against British ground radar. The site at Mont Couple behind Calais was used at first, but was gradually extended to a chain of ground jammers along the whole Channel coast, and ultimately there were sufficient to have every identified British ground radar station covered by at least one suitable jammer. 31. In 1940 the stations jammed were those in the 20 - 30 mc/s and 50 – 90 mc/s bands. Both ground stations and airborne apparatus carried in Ju.52's were used. By 1941 a chain of Karl jammers which also covered the 200 mc/s band had been set up along the whole coast. 32. During the initial period, various efforts were made to spoof our early warning radar. The first of these was the brain-child of Dr. SCHOLZ and was tried out in 1940. 33. Pulses radiated by one of our C.H. stations were picked up on the ground and re-transmitted on a different frequency to an aircraft flying some way behind the Channel coast. The aircraft re-transmitted the original radar pulse on the C.H. frequency, but a slightly different phasing, so that a phoney blip located over the Channel was received. Owing to the ease with which this phoney blip could be D/F'd and the spoof immediately revealed by a second station, this method was soon discarded. 34. About the beginning of 1941 a special experimental equipment called the Garmisch Partenkirchen, which produced no less than five different phasings and five phony blips, was tried out. For the same reason this was not much used in practice. How the "S & G" Got Through. 35. The first big operation on which the jamming chain against British radar ground stations was used was on the occasion of the passage through the Channel of the Scharnhorst and Gneisenau in February 1942. A few days prior to the operation Dr. SCHOLZ was specially brought from Berlin to supervise it. 36. The radar cover of our C.H. and C.H.L. had been carefully plotted and it was ascertained that the ships would come within its range as they passed off Fecamp, where they were due at 10 a.m. At that hour every available jammer was switched on. The fact that the ships passed through unscathed was, in P/W's opinion, the best proof of the effectiveness of the German countermeasures. P/W was not aware that we had either decimetre or centimetre radar in operation at this time. Siege of Malta. 37. In July 1942 P/W was sent to Sicily to take charge of an intensive jamming programme which he suspected was to be the precursor of the invasion of Malta, although he was never told so officially. The first four Karl jammers on 193 mc/s were brought into service in the neighbourhood of Noto en 3rd July 1942 and the number was later increased to eight, to cover both A.I. and ground stations. They were beamed on to the sites at Malta. These transmitters were half kilowatt, C.W. amplitude-modulated at 100 c.p.s. using an unsmoothed HT supply, plus a modulation of 150 - 200 kc/s. The reason for the amplitude modulation being unsmoothed was that there was a shortage of high-voltage smoothing condensers. 38. After a time it was observed that we had adopted frequency changes. The German jammers were however, controlled by monitoring receivers on sites so arranged that the jamming signals and the original radar signals could be seen side by side on a C.R. tube; this enabled the frequency change to be followed within a few seconds. A great aid to them in following and preparing for these changes was that new frequencies were invariably tried out during the day from Malta and the monitoring service could warn the jamming operators of frequencies likely to be employed. 39. It was noticed that signals on the 50 - 80 mc/s frequency were switched on during a raid and it was suspected that they were due to the height-finding equipment of the radar station controlling our night fighter which seemed to operate in a similar fashion to the German Würzburg. This opinion was confirmed when "Y" service heard a ground station say that they could give the range of the bandits but that height measurements were not yet available. 40. To jam the "height-finding" frequencies a Ju.52 fitted with eight jammers covering the 50 - 80 mc/s band was brought down to Catania. An hour before a raiding force became airborne this aircraft left Catania to patrol half way between Sicily and Malta and jam this band. 41. After P/W left, jamming was also carried out on the 42 mc/s band with the same type of Karl ground transmitter as was used for other frequencies. Modulation of Jammers. 42. When jamming out ground radar, H.F. modulation was always preferred to noise modulation since the equipment necessary to produce a given effect with noise modulation was much more extensive than for H.F. modulation, and in particular a large number of high-power valves was needed. The greater efficiency of noise modulation was not considered sufficient to warrant the extra power and extra equipment needed. It was also thought unlikely that H.F. modulation could be filtered out of the radar receiver without severe deterioration of the picture. Düppel (Window). 43. The idea of using window to spoof ground radar had occurred to the Germans in 1941 and a series of experiments was carried out in great secrecy over the Baltic in February 1943 (See A.D.I.(K) 334/1945 Part, IV). Very careful arrangements were made to ensure that the wind was in the right direction so that the window strips would fall into the sea and not in Sweden, or even on German occupied territory. 44. The effect of window was observed on all types of German ground radar deployed along the Baltic coast, and its efficacy as a countermeasure was realised. The German codename for Window was "Düppel" - a word with a very similar pronunciation to the German word "Dipol" (= dipole), indicating the function of the metal strips. 45. The Signals Staff realised that Düppel was a two edge weapon and although its development was completed sometime in 1942, and a certain quantity was manufactured, no use was made of it for fear of Allied retaliation. 46. The whole project was, in fact, kept so secret, that only a very few high officers and technical experts in the G.A.F. were aware of the scheme. So closely was the secret of Düppel guarded that the scientists were not even allowed to carry out research work to discover what anti-window measures could be applied to the various types of German radar. 47. Although the Germans were free to employ window as a countermeasure over this country after its first use by the R.A.F.in July 1943, it was realised by the Signals Staff that they had never used it to such good effect as the Allies. 48. The reason was that the small German bomber aircraft like the Ju.88 could only carry a very limited quantity and therefore could not produce a real window cloud. They therefore decided to drop small quantities scattered over a wide area in the hope of deceiving the night fighters and of producing the impression that a larger number of aircraft was engaged on a certain raid as well as in the hope that ground controllers might vector night fighters on to a window cloud instead of on to an aircraft. Final Policy against Early Warning Radar. 49. The general policy followed by the G.A.F. at the end of the war with regard to the countermeasures against early warning metric radar appear to be summarised in a document dated December 1944, which states that the use of ground jammers against all ground radar is, in principle, particularly desirable during German bomber raids on enemy territory, but that there is no advantage in using airborne jammers because the frequency of the ground radar has to be constantly monitored and followed. 50. This principle was not strictly adhered to because an airborne jammer for the 170 - 220 mc/s band named Kettenhund was used to a small extent in raids on the South-West of England in May 1944 (sec A.D.I.(K) 321/1944) but it was not considered to be very effective. 51. Some attempt was being made to develop a noise-modulated airborne transmitter named Wolke but it was never used operationally. METRIC A.S.V. 52. The first attempts to jam A.S.V. were made in the Channel in the summer of 1942. During the preparations for the proposed invasion of Malta it was found that reception of British A.S.V. transmissions was obtained at extraordinary ranges in the Mediterranean area. This was ascribed largely to the fact that the receivers were placed as high as possible - in some cases 3,000 foot above sea level - and attempts were made to jam A.S.V. by using Karl transmitters placed near them on high points of the coast of Sicily, Greece and Crete. 53. At about this time a Sonderkommando KOCH was formed and based at Athens-Kalamaki. Its duties were to monitor and jam A.S.V. and it was thought they used the Kobold airborne transmitter with a frequency range of 160 - 200 mc/s. It had the disadvantage that it could only be built into large aircraft and some doubts arose as to whether it was very effective. 54. Up to the of the war, the Bari ground jammers continued to be employed against A.S.V., particularly along the length of the Adriatic and along the Norwegian coast at points where German coastal convoys obtained no cover from islands lying off the coast. 55. In mid-1943 U-boats leaving Brest were suffering a serious increase in losses owing, it was thought, to the use of our A.S.V. a Sonderkommando Rastädter was formed with a few He.111 and Ju.88 aircraft for the purpose of listening to British A.S.V. on metric and centimetric wavelengths and determining what type of radar was being used with such effect (see A.D.I.(K) 38/1944). These aircraft carried, amongst other receivers, both Naxos and Korfu. The net conclusion reached as a result of these investigations was that Coastal Command was using a centimetric frequency (presumably H2S) for which the Germans had no jamming transmitter. 56. The Allied attacks on U-boats took place so far from the coast that ground jamming of A.S.V. on metric wavelength was impossible and too many aircraft were needed to carry out efficient airborne jamming. It was feared, too, that if airborne jamming were carried cut, it would only attract A.S.V.-equipped aircraft or surface vessels to the vicinity, and be a proof that U-boats were about. 57. Warning receivers were therefore installed in U-boats. The first of these - Metox - was used against metric A.S.V. It suffered from the disadvantage that its local oscillator radiated strongly, and it was suspected that we could home on to this radiation from 100 km.; the Samos receiver later replaced Metox. A form of Naxos was introduced to provide warning against 9 cm. A.S.V. and was used up to the end of the war. METRIC A.I. 58. The weak link in the British night fighter organisation was, as already mentioned, considered to be the R/T communication; the airborne jamming of British A.I. itself by German bombers or special R.C.M. aircraft was not considered a practical measure because it was believed that British night fighters would be able to home on to the jamming aircraft and severe losses were therefore to be expected. 59. No intentional jamming of Mark IV A.I. was ever carried out from the air or from the ground, although it was considered possible that Karl jammers against G.C.I. and harmonics of the Heinrich transmitter against Gee, and possibly of all transmitters jamming Oboe and C.H., may have had some effect. 60. In this connection P/W stated that it was extremely convenient for the Germans that we had so many equipment working on such a restricted frequency band in the 200 mc/s region. This fact has eased their jamming problem very considerably. GEE. 61. The value of Gee system of navigation referred to by the Germans as Hyperbel, is that it allows an aircraft to navigate by a radar method without transmitting any signals which could be used to D/F the raider from the ground. This threat was realised by the Germans in March 1942 when the existence and method of operation of the system was first discovered, but the decision to jam Gee was not taken until August 1942. 62. A jamming transmitter was hurriedly improvised out of the standard A.S. ground transmitter used for R/T traffic with the FuGe.16. This was modulated with the standard "Mont Couple" modulation at 150 - 200 kc/s. Prior to this makeshift coming into use, a certain Dr. MÖGEL had experimented locally with jamming transmitters but these only operated for a short time and no details are known of them. 63. An order for a large number of suitable jamming transmitters for countering Gee was placed in August 1942 and the first of these - 1/2kw. Heinrich - went into service in November 1942. As the Heinrich transmitters became available in quantity they were deployed all over Germany and by the end of the war some 270 were in operation against Gee. 64. Estimates of the effectiveness of jamming by the deployed Heinrich transmitters were obtained by flying captured Gee equipment and by questioning British P/W. The conclusion reached was that before the invasion the Gee chains were of no use further East than 4°. 65. After the invasion the situation changed, and in August 1944 a so-called Stördorf (= jamming village) was set up on the Feldberg in the Taunus area and controlled and run by the Reichspost Zentrale. Installation began in August and in September the first equipment came into use. 66. The Gee countermeasures from the Feldberg site were of a different type. In addition to a number of normal Heinrich transmitters, three new types of much greater power were used. These were Feuerzange, a very powerful pulse transmitter with a peak power of 1 megawatt, Feuerstein with a peak power of 120 kw. at 5,000 pulses and a smaller transmitter, Feuerhilfe with a power of 30 kw. which had been improvised by Köthen. These three powerful transmitters were used to pick up the Gee transmissions and retransmit them but with a very slightly different p.r.f. A keying arrangement was incorporated so that the pulses of the master and slave stations could be imitated. 67. In the immediate neighbourhood of the site it was expected that the pulse powers used would be so high that the Gee presentation screen would be completely jammed. At greater distances aircraft would receive on each frequency used three or four false pictures broadcast by the Feuerzange and Feuerstein. As they transmittal their spoof pictures on p.r.f's which differed only slightly from that used by the British stations, the effect produced was that the false pictures wandered very slowly over the true pictures so that it was difficult for an operator to tell which was the correct set of blips. 68. At the beginning an insufficient number of sets was available to carry out this spoofing on all the chains, but by January 1945 the site was fully equipped. The Germans were convinced that this system was successful because on 2nd March 1945 at 1230 p.m. a number of fighter bombers paid them a very unwelcome, visit and completely destroyed the site. 69. Consideration given to the idea of jamming the link between the Gee ground stations, was never carried out as it was thought that we would certainly anticipated such measures by providing a number of reserve links, possibly on centimetre wavelengths, or oven co-axial cable links. 70. When Gee jamming was first properly undertaken towards the end of 1942, a large number of monitoring stations placed about 100 km. apart were erected around the occupied coast form Brest to Norway. Each site had two Heinrich transmitting units, one operational and one spare, and monitored all possible wavelengths. Changes of phase were also reported so that German aircraft flying with Gee equipment could be notified by W/T. 71. The whole problem of Gee jamming was considerably simplified on the few occasions that we made unexpected frequency changes, because our transmitters lined up on the new frequency before they were used operationally. Had this not been done the effectiveness of the German jamming program, might have been considerably reduced. LORAN. 72. As has been mentioned in a previous report of this series, the discovery of Loran came as a great shock to the Germans because Professor von HANDEL had convinced himself that a long-range, comparatively long-wave pulse system would be too inaccurate for employment as a means of navigation. The Germans' first knowledge of the system was obtained about the middle of 1944 when maps were captured, and ultimately a complete apparatus was obtained from an American aircraft. 73. Attempts were made to jam it, and by March 1945, 10 to 20 one kW noise jammers, which jammed the ground wave satisfactorily within a radius of 50 to 100 km., were in operation. At this time transmitters to meacon the pulses were being built and consideration had been given to jamming the synchronisation of the transmitters from the ground, using a 100 kW. C.W. transmitter which was to be erected as near the front line as possible in order to be near the ground link. 74. The transmitter was ready and hat been taken to Thüringen but the disruption of transport and communications prevented it ever being used operationally. G.II. 75. The same equipment was used for jamming G.H., known to the Germans as Diskus, as was used for jamming Gee. 76. A number of jamming villages (Stördörfer) with from two to eight Heinrich transmitters were deployed throughout Germany. It was calculated in December 1944 that at 20,000 feet G.H. could only be received and used up to a line joining Emden and Kassel and from there swinging South in an arc to Stuttgart, while at 33,000 feet reception was thought to be possible up to an arc joining the mouth of the Elbe, Weimar and Augsburg. 77. In addition, it was planned to use the powerful Feuerzange and Feuerstein transmitters in an attempt to trigger-off the ground stations from the Feldberg/Taunus Stördorf used to jam the Gee chains. OBOE - METRIC WAVELENG. 78. In the autumn of 1942 a new type of radar signal in the 200 mc/s band was picked up by the German monitoring service at Calais. Statistics were kept and it was observed that these transmissions occurred mainly at night, and seemed to be associated with British M.T.B. activity in the Channel. 79. In about June 1943 the same type of radar signals was heard in Essen during a very heavy bomber raid on Cologne and Dr. SCHOLZ was able to correlate them with the dropping of T.I's visually observed. It was realised at once that these signals were the same as those heard at Calais and an immediate investigation was carried out. For this purpose a "noise investigation commission" was formed and a special experimental Freya with a number of D/F receivers was set up. The Freya was used to plot the course of the T.I.-carrying aircraft while the receivers D/F'd and monitored the signals. 80. Some 6 to 8 weeks after the signals had first been attributed to path-finders, a satisfactory story had been worked out by the Germans as to how Oboe, called by them Bumerang, worked. When this had been accomplished, subsequent Oboe raids were systematically monitored by the normal monitoring service. 81. At this time (August 1943) plenty of jammers were available because of the reserve apparatus available for use against 200 mc/s radar stations on the Channel coast. Ten sites were chosen to give jamming coverage over the Ruhr and eight ½ KW MCW Karl jammers employed at each site. The standard Mont Couple modulation also used against C.H.L. stations was applied giving 150 mc/s sine wave modulation at 100 c.p.s from an unsmoothed H.T. line. 82. The radio frequency was determined by picking up the aircraft return signal and tuning the jamming transmitter until the normal signal failed. Four frequencies in the 200 mc/s band were ultimately detected, but though the ground station frequencies were found to be steady, those of the airborne transmitter were not very stable. 83. Aerials recovered from crashes appeared to be mounted sometimes en the starboard wing and sometimes on the port wing of the aircraft. This fact, combined with some information obtained from a British P/W, caused the Germans to believe that the aerials were directional, and in order to jam more successfully, all transmitters were moved to the West of the Ruhr. 84. Jamming was almost entirely confined to the Ruhr area because this territory was far away, the most important target within the limited range of Oboe. The Germans were greatly relieved when Oboe was used against the rocket sites in Northern France, as the pressure on the industrial Ruhr was thereby reduced. From about December 1943, intermittent attempts were made to jam Oboe ground stations from the site at Mont Couple behind Calais. These were not very successful - a fact which was attributed to the beam width of British aerials. 85. In June 1944 a new form of jamming which was known as the Ballverfahren was suggested. This was essentially meaconing, using an A.B.G. responding transmitter in the hope of confusing the aircraft's return signals to the ground station. It was believed to work well, and P/W quoted as an example a raid on Nürnberg when aircraft deviated from their course as soon as the jamming was switched on and returned to their course when it lifted. 86. An instance of the success of Oboe jamming on the Ball system was quoted. In June 1944 an oil installation - possibly Wanne-Eickel - was the target, and all Oboe aircraft were successfully jammed. The T.I's were dropped late and some 8 km away from the target. As a result of this the main bomber force spread out and many aircraft were shot down. 87. Only one metric Oboe receiver fell into German hands and that was 90% destroyed; although the Germans knew the principle, therefore, the details of the airborne set were lacking, and the effectiveness of jamming could only be judged by the accuracy of bombing. 88. By observing on a Freya the point at which bombs left the aircraft, the Germans estimated the accuracy of Oboe as 300 x 300 metres for bombing from 9,000 metres, but a further 200 metres of ballistic inaccuracy occurred, giving an effective error of 500 x 500 metres in the Ruhr area. 89. The success of jamming Oboe was considered to depend partly on the training of personnel, so it was less effective on a new target than on an old target which had been jammed before. It was finally believed that the jamming was 90% effective. 90. The Germans claim to have been so familiar with Oboe that they were able to plot aircraft and withhold their jamming until the aircraft turned onto the bombing run. They were then able to identify the real target and localise the air-raid warnings so as to disturb industrial production in the neighbourhood as little as possible. 91. It is of some interest that on several occasions there was a consistently good concentration of bombs in an open field near Leverkusen, which P/W presumed to be due to an error in computing the exact location of the target. COUNTERMEASURES AGAINST RADAR. OBOE - CENTIMETRE WAVELENGTHS. 92. Signals which were recognised as Oboe by the type of coding were detected on a wavelength of 9 cm on the Channel coast about the spring of 1944. The normal monitoring service had previously intercepted unexplained 9 cm. signals in October 1943 but had not finally connected them with Oboe. 93. When 9 cm. Oboe was recognised, it presented the Germans with a great problem, as no jamming valves were available for that frequency and German intelligence had not given any hint that a centimetre version of Oboe might be produced. 94. By July 1944 a valve called LD.7o (= 7 ohne = without) had been produced, which was an LD.7 valve without cooling fins. A transmitter unit called Feuermolch, tuneable from 8.6 - 9.6 cm., pulse modulated and giving 3 kW peak pulse power, was than built. The whole apparatus, a Feuermolch transmitter together with a mirror reflector to achieve 200 km. range by beaming, was called Feuerball or A.B.G. (Anti Bumerang Gerät). 95. Jamming on 9 cm. Oboe was first used in operations in October 1944 at Weser and Leuna. The Feuerball jammer was used as a pulse repeater, after the frequency had been established by interrogating the aircraft. The jammer then set up ringing between the aircraft and jammer on the Ball system used against metric Oboe. 96. The latest type of centimetric meacon responder called Feuerburg had receiver and transmitter aerial mechanically linked to follow individual aircraft, the jammer aerial system giving a beam of 13° width. The aircraft was followed by hand by means of a spinning dipole in a receiving dish. 97. According to Dr. SCHOLZ the wavelength originally used by British centimetric Oboe was 9.26 cm. Sites were set up with both 200 mc/s and 9 cm. jammers so that either could be selected by a change-over switch on the receivers. 98. The jamming of Oboe by spoof massages was never tried although the meaconing jammers were fitted with a keying arrangement which would have allowed them to attempt this. 99. Oberleutnant Dr. BÄHRE of Ln. Versuchs Regt. Köthen had doubts as to the effectiveness of the Ball system and had proposed building a jammer with a very high p.r.f. to saturate the aircraft receiver with pulses so that the strength of each individual pulse re-radiated by the aircraft transmitter would be greatly reduced and the range of the system would therefore be considerably decreased. The Roland J transmitter which had been designed for H2S countermeasures was to be adapted by Lorenz for this purpose, but the idea was never put into operation as the end of hostilities occurred shortly after it was made. 100. An example of the success of jamming centimetric Oboe was quoted and concerned a series of five raids on Gotha. Three attacks, each with between three and five aircraft, were unjammed and all scored hits on the railway station. The fourth attack was jammed and no hits were scored on the same target. The fifth attack was again let pass without jamming and the station was once more successfully hit. 101. A further proof of the efficiency of the Ball system was that in plotting aircraft a diversion from track could be induced when the jammer was switched on and the aircraft would return to track if the jammer were switched off again. 102. On the only occasion on which a 9 cm. Oboe aircraft was known to have been shot down, it crashed in the Zuider Zee in shallow water where it could neither be reached from shore nor by sizable ship, and it was not possible to salvage the equipment. As a result, the Germans never obtained any Mark II Oboe equipment and detailed information as to how the system worked was always lacking. There was no explanation, for instance, of why certain aircraft transmitted pulses which did not appear to have normal Oboe coding, although the aircraft flow at heights and along tracks which obviously identified them with Oboe procedure. 103. No advance information of the target could be obtained from these aircraft but this was easily obtained from the W/T transmissions between ground stations. The W/T channel used was also monitored in order to see if jamming had been successful. It was also noticed that some aircraft would not respond to the interrogator but the reasons for this were not fully understood. These aircraft seemed to be operating on a wavelength above 9.6 cm. 104. A new valve to cover the 9.6 - 10.6 cm. band was being produced by Dr. GROOS. It was a 100-watt Klystron and it was proposed to jam with its aid as soon as it was finally produced. 105. Towards the end of the war there was a great increase in the daylight use of Oboe but P/W did not believe that the Americans had ever used it. With so many aircraft over Germany towards the end of the war correlated evidence was not available. H2S. 106. Shortly after the discovery of H2S in January 1943 panic orders were given for the production of a jammer. Later in the year Roderich, which was manufactured by Siemens and which used a Magnetron of theoretically 5-watt power, was made available. The transmitters were unbeamed and the power was so low that they were useless. By 1944 the use of Roderich had been discontinued. 107. The difficulties of jamming highly-beamed centimetric radar were so great that it was decided that all that could be done was to attempt to defend a few vital targets. The first target to be chosen was the Leuna works which was considered a good target. 108. The Reichspost Zentrale was called on for assistance and Dr. GROOS of that institution successfully developed a Klystron valve, which was a water cooled 100-watt valve tuneable by hand from 8.5 - 9.5 cm. This was built into the jamming transmitter which was known as the Postklystron. 109. In order to concentrate as much of the energy as possible to the aircraft, horns or paraboloid aerial reflectors were employed with the transmitters. About eight sites around Leuna were chosen, bearing in mind that the attacks always seemed to use a route coming in from the North, presumably because the best H2S pinpoints lay in this direction. 110. Four Postklystron transmitters were placed on suitable sites and spaced in frequency across the observed 30 mc/s band of H2S by putting them about 5 mc/s apart and making use of the side bands from 2 - 10 mc/s single frequency amplitude modulation. This barrage was used with low directivity. 111. A second type of jammer employed made use of the Roland transmitter built by Siemens, which had a 30° beam, but its development was abandoned about March 1945, as it was not considered very successful. 112. In yet a third system Postklystrons were used with a beamed aerial system giving a lobe 6° wide. The transmitter was coupled mechanically to the D/F, receiving aerial of a Korfu receiver, its aerial being provided with rotational eccentric split. The receiving aerial was trained on a single H2S bomber, which was followed manually. 113. The detection range for setting up was about 300 km. With the less beamed type, Roland, effective jamming ranges up to about 30 km had been obtained but with the narrow 6° beaming the H2S tube was completely obliterated at 40 km if the beam was focussed on the H2S aircraft. 114. One P/W had flown with H2S equipment installed in German aircraft in order to carry out experiments in ground camouflage against H2S with the aid of corner reflectors. The conclusion was that corner reflectors were ineffective. It had originally been planned to cover arms of the sea and lakes with corner reflectors, but in the first place too many were needed, and in the second place arrangements had to be made for these to remain fixed in a certain orientation in order to produce an effect. 115. Another suggestion had been made that metallic powder could be used to increase the reflectivity of an area. This was obviously no use as camouflage for a target, which was the end originally in view. Consideration was given to producing a dummy target with its aid but it was concluded that the quantity of powder necessary was so enormous that it was not a practical proposition. H2X. 116. The Germans had such leeway to make up with the production of 3 cm valves that no active countermeasures against H2X had been put in operation up to the end of the war. Development of a transmitter called Roland 2 was started in December 1944 with Telefunken Ceramic 3 cm valves believed to be known by the designation LD.72 and LD.77. 117. The set was to be modulated by 100 kc/s pulses and to sweep through a small radio frequency band. The power achieved was 50 watts average. With horn aerials a 20° beam was to be achieved. The range against an H2X set which had been captured undamaged at Wiesbaden was 20 km. in the initial experiments. A.I. 118. Owing to the strong beaming and method of sweep of centimetre A.I. the G.A.F. was doubtful if any jamming would be possible. No airborne transmitters against centimetric radar were developed. -o-o-o-o-o-o-o-o-o-o ACKNOWLEDGEMENT. Acknowledgements are due to the various technical bodies, both British and American, who collaborated in producing the technical information contained in this report. A.D.I.(K) and S.D.Felkin, U.S. Air Interrogation. Group Captain. 29th August, 1945. A.B.G. (DALL) The A.B.G.(Anti Bumerang Gerät) meaconing jammer was first used in June 1944 and was an idea fathered by P/W. It was a responder beacon which was employed against Oboe to set up "ringing" between the aircraft return signal and the A.B.G. so that the aircraft return to the ground station was confused. The jamming transmitter had a 20 - 30 kW power in the case of the model used against 200 mc/s Oboe. In the A.B.G. used against 9 cm. Oboe (Feuerball) the power was 3 kW. BRESLAU. This was the pulse modulated transmitter with a range from 20 - 250 mc/s developed and built in the G.A.F. laboratories in PARIS. It was believed to have consisted of six or eight ½ kW transmitters. Some 50 sets only were put in hand and about half of them were completed. It was thought that they had been used against ground radar stations along the Channel but with what success it was not known. FEUERBALL. This was the name for the A.B.G. centimetric responder used to jam centimetre Oboe. The jammer was used as a pulse repeater and set up ringing between the aircraft and the jammer. It consisted of a transmitter using a klystron valve developed by the R.P.Z. which covered the frequencies 9.0 - 9.6 cm., backed by a beaming reflector. The peak power was about 3 kW. FEUERBURG. In order that the Feuerball transmitter should be beamed on to the transmitting aircraft, a beamed receiver was mechanically linked to the Feuerball set. The receiver was operated so that the receiving mirror was aligned on the aircraft and the Feuerball paraboloid mirror followed any changes of elevation or direction made by the receiving operator. This complete set-up of beamed Korfu receiver with a Feuerball beamed transmitter was known as Feuerburg. FEUERHILFE. This was a smaller form of Feuerstein improvised by Köthen with a peak pulse power of 30 kW. FEUERLAND. This was a two-stage inductive transmitter (final stage LS.1000) manufactured by Blaupunkt and served the same purpose as the Karl II. The first production sets were ready in March 1945 and were believed to have been sent to the Holstein area, but they were never used operationally. The frequency of the Feuerland could be adjusted from 30 mc/s to 300 mc/s by means of interchangeable H.F. coils. Different types of modulation could be introduced according to whether it was to be used against R/T or radar. Against R/T it was known to have had the four-tone chime modulation described under Nervtöter below. It could also be used with noise modulation with an adjustable bandwidth up to 2 mc/s. The power output was about 350 - 500 watts. FEUERMOLCH. This was the name given to the centimetric transmitting equipment of the Feuerball. FEUERSTEIN. The Feuerstein designed by Telefunken was used for producing a false picture on Gee sets, the keying of the pulses being carried out by equipment supplied by Telefunken and Siemens. A number of these sets were installed on the Feldberg. It was a high-power pulse transmitter at frequency range of either 20 - 52 mc/s (known as the Feuerstein 1) or 48 - 90 mc/s (known as the Feuerstein la). At a p.r.f. of 5,000 cycles it had a peak power of 120 kW. FEUERZANGE. This was the highest-powered pulse transmitter possessed by the Germans and was used in 1945 on the Feldberg to provide spoof Gee transmissions. The transmitter, developed by Dr. FREUDENHAMMER and built by Siemens, was water-cooled and could be modulated in exactly the same way as Feuerstein. The frequency range of the transmitter was 20 - 87.5 mc/s and at a p.r.f. of 5,000 cycles a power of 1 megawatt was claimed. It was considered a very effective set but only came into operation towards the end of 1944. GARMISCH PARTENKIRCHEN. Garmisch Partenkirchen was believed to be an improvised airborne apparatus, probably manufactured by Neufeld and Kuhnke of Kiel. It was used to a very limited extent in 1941. It consisted of a receiver which picked up a ground radar transmission and re-transmitted on the same wavelength but returned no less than five different pulses with slightly different phases with the object of creating false echoes. As these false echoes could be immediately identified if a second ground radar D/F’d the jamming aircraft, the idea was carried no further. GEWITTERZIEGE. An experimental spark, ground jamming transmitter for employment against flight radar and using a 1/2 wavelength dipole aerial in front of a reflector, was given the code name Gewitterziege. The band width was very large but it was claimed that it was an effective jammer at close range. HEINRICH. This transmitter was developed by the Reichspost Zentrale in 1942 with the specific intention of providing the G.A.F. with a jammer against the Gee navigation system. A large number of these sets was built and deployed all over Germany to jam Gee. A set of the same type, from which Heinrich had been developed, was used in Sicily in July 1942 for jamming the radar stations in the 50 - 80 mc/s band in Malta. In its ultimate form, Heinrich II, the transmitter had a power of 500 watts and covered the band from 20 - 90 mc/s in four separate sections. For this output it used four LS.180 valves arranged in parallel push-pull. It was 100% modulated by 150 kc/s sine wave with the addition of 100 cycle ripple obtained from an unsmoothed H.T. power supply. The set needed only two controls, one for the main tuning and one for the aerial coupling. The aerial consisted of a wide band dipole of squirrel cage circular section, with normal tapping at the feeding point. This one aerial was used in the entire frequency band from 20 – 90 mc/s. It was stated to have a standing wave ratio of 20% in voltage. KARL I. This was the standard jamming transmitter for use against British radar and was designed to cover the frequencies 90 - 250 mc/s in two bands. Development work on it was started at the end of 1940. The transmitter employed four LS.180 valves and had a power output of between 300 and 500 Watts. It was modulated by the standard Mont Couple 150 kc modulation on which a 100-cycle tone coming from an unsmoothed 50-cyle source of supply was imposed. The type of modulation employed could not be changed in the field. KARL II. This was on improvement of Karl I with few changes in the electrical specifications but it was really composed of two more powerful Karl I units with a common feed. It was also modified so that any desired standard type of modulation could be substituted at the site where it was employed, thus obviating the necessity for returning the transmitter to the factory, as was the case with Karl I. The Karl II employed an LS.1500 valve with an output of 2 kW, and besides being used against ground radar, it had been modified for use against R/T with the Post type of modulation. It was not known what degree of success had been achieved with this set. KARUSO. The original Karuso I was improvised by the R.P.Z. with the specific object of providing aircraft with an airborne transmitter to jam the R/T link between the British ground control stations and British night fighters. It was origina11y intended to sweep through the whole 100 - 120 mc/s band. 0wing to the relatively large frequency sweep, however, jamming was not vary effective, so it was manufactured in two forms, to sweep from 100 - 110 or from 110 - 120 mc/s. It had ultimately an effective range of about 5 km. and a power of about 30 Watts. Altogether, only 100 sets were manufactured. The designation Karuso II was given to a development which never got farther than the laboratory stage, but Karuso III was produced and covered the 100 - 150 mc band. The width of the jamming band was only 3 mc/s and the frequencies used was set up on the ground according to intelligence information given by the German "Y"-service. It was not known whether this set was used operationally. KETTENHUND. Kettenhund was a 30 watt air-born jammer developed in 1943 by a certain KETTEL of Telefunken covering the 170 - 200 mc band. It was used against British ground radar stations in raids over South-West England in 1944. Tests with the set led the Germans to the conclusion that it was not very effective. Modulation employed was a triangular wave with a frequency of several hundred kc/s. KLYSTR0N. This was the name commonly applied to a centimetre jamming transmitter witch was also referred to as the "Postklystron". It acquired this name because it made use of a centimetre klystron valve developed by Dr. GROOS of the Reichspost. A power of 100 watts was claimed for it. It was a CW jammer which could be tuned by hand between 8.5 cm. and 9.5 cm. It was fitted with a horn aerial to be aligned on the approaching H2S force. It was claimed that at a range of about 40 km. the H2S tube was completely obliterated when the Postklystron was focussed on an individual aircraft. This set came into operation about March 1945. KOBOLD. The Kobold was an airborne set designed by the Post specifically to jam A.S.V. and was originally used in the Mediterranean in conjunction with a Karl transmitter working from the ground. It was, in effect, half a Karl transmitter and used two LS.180 valves. A modulation of about 400 cycles originating from the aircraft transformer was superimposed on it. It had the handicap that it could only be built into very large aircraft. NERVTÖTER. Nervtöter I was designed as an airborne transmitter to jam Allied R/T but considerable difficulties were encountered in tuning it in the air to the frequency observed and it was never used in operations. As a result of the criticism made by T.L.R., the Nervtöter II, which was also believed to be known as FuGe. 40, was to be developed. This set employed an LS.50 valve in the final stage and the frequency of the R/T was to appear as a blip along is time base on a cathode ray tube, while the frequency, to which the transmitting jammer was adjusted, appeared on a similar blip on a second time base on the tube. By setting these two opposite each other the operator could easily see that he was jamming the required frequency. A so-called chime modulation of four changing tones was used. The power output was 25-30 watts and the frequencies ranged from 90-160 mc/s. Wide band aerials were to be used. This set had not got beyond the experimental stage by the end of the war. OLGA. Olga was a self-excited, grid-keyed, one valve transmitter (LS.180) developed by the Navy and had a frequency range of 150 - 200 mc/s and an output of about 300 watts. It was believed that a p.r.f. of 500, 700 or 900 cycles was used. This jammer was an early type used against British coastal watch radar without much success. RODERICH. This was the name applied to the first set developed by Siemens for jamming H2S when panic counter-measures were called for early in 1943. It used a magnetron valve with a maximum power output of 5 watts and was virtually of no use whatsoever. It took some months to develop; in the meantime, German knowledge of how to Jam H2S had increased to such an extent that it was never used. ROLAND. The Roland jammer was developed for use against H2S by Dr. WEHRMANN of Siemens and was said to employ a triode transmitter valve designated L.D.72 or possibly L.D.75. The wavelength was 8.5 - 9.5 cm. and with the aid of a horn aerial it produced a 30° beamed transmission, modulated, it was believed, by 100 kc sine wave and pulses of an unknown p.r.f. It had less than 50 watts average power. The range at which obliteration of the H2S tube was claimed, was about 30 km. The Roland II was the name applied to an attempt to produce a similar set on 3 cm using, it was thought, a LD.77 triode valve and a horn aerial a 20° beam. It is doubtful if it was used operationally as the valves had a very short life. STARNBERG. This was believed to be the precursor of Kettenhund and was designed by D.V.L. Adlershof in about 1940 but never used. In a document there is an indication that attempts were later made to use it as an R/T airborne jammer; A.D.I.(K) 231/1944 also gives an account of preparations to use the Starnberg operationally. WOLKE Wolke was believed to be the code name applied to the first German attempt to imitate a noise jammer like that used by the Allies. It was believed to use two L.D.5 valves in the final stage and to have a carrier frequency of 90 mc/s. The average power output was 15 - 20 watts, the width of the noise band being about 2 mc/s. As a result of the examination of Wolke the conclusion was reached that noise modulation required too many valves and too much power and that with the some number of valves a better effect could be obtained with other types of modulation. The set was therefore used for training night fighter crews to see through electronic jamming of SN.2." |
RADAR AT DOUVRES
SECRET A.D.I.(K) Report No.320/1944
THE FOLLOWING INFORMATION HAS BEEN OBTAINED FROM P/W AS THE STATEMENTS HAVE NOT AS YET BEEN VERIFIED, NO MENTION OF THEM SHOULD BE MADE IN INTELLIGENCE SUMMARIES OF COMMANDS OR LOWER FORMATIONS, NOR SHOULD THEY BE ACCEPTED UNTIL COMMENTED ON AIR MINISTRY INTELLIGENCE SUMMARIES OR SPECIAL COMMUNICATIONS. A GERMAN RADAR STATION AT DOUVRES. 1. The information contained in this report was obtained from selected P/W of the 8th Kompanie of Ln. Regiment 53, who were captured on 17th June 1944 at a Radar station which they were manning 2 km. to the East of Douvres. The site consisted of two Würzburg Riese and two Freyas without the A.N. attachment; one of these Freyas was of the mobile type, and was not operational pending its being changed for one of the fixed type. 2. The operators as a whole were not particularly knowledgeable, but were able to give some interesting information on the way in which Allied air attacks affected operational efficiency of the station. One member of the station, an officer, was more knowledgeable than the others and added some odd scraps of information on other Radar equipment, which are summarised in this report. DAMAGE BY ALLIED AIR ATTACK. 3. The beginning of May saw the opening of almost daily air attacks on the Radar station at Douvres; from this time until D-Day the site was subjected to bombing, machine-gun and rocket projectile attack from Thunderbolts, Typhoons and Spitfires. 4. Surprisingly little resulted from those attacks; eight men had been killed and one barrack building had been burnt out, but the Radar installations themselves, protected as they were by heavy brick work, were practically undamaged. Apart from short intervals of a few hours for repairing cables and aerials severed by M.G. fire, the installations were, according to P/W, continuously in operation. 5. It was stated R.P. attack was particularly ineffective, but that machine gun fire into the cabins of Radar installations was both feared and effective. During air attacks, therefore most of the personnel of the station, including crews from the Würzburg and Freya cabins, went to the "Bunker" shelters. 6. On the night of 6th/7th June, the Kompanie had been busily employed in plotting Allied shipping and at 0100 hours on that night the Würzburg had plotted same 100 ships, which information was passed through to Jafü 5. At 0300 hours a large number of bombs fell in the neighbourhood and all the personnel left their posts to take to the shelters, leaving the apparatus unattended. 7. From D-Day onwards the Würzburgs and Freyas were kept operating even with the added weight of artillery and tank attack and the equipment was, in fact, operational until a few hours before the site fell to the Invasion Forces. It is, therefore, clear that in an operational sense the site survived nearly five weeks of constant attack. 8. When capture became imminent, however, all technical apparatus on the site was destroyed by explosive charges. The personnel put up a good defence, and it was not until the Allied tanks broke through the protective minefield that the station finally surrendered. PLOTTING ROOM. 9. The plotting room on this site, which correlated data received from the Freya and Würzburg, was housed on the top floor of a two-storey "Bunker" - a box like building partly sunk in the ground and constructed of concrete two metres thick. It had originally been intended that, in addition to handling normal Würzburg and Freya searches, the plotting room should also be employed for control of night fighters, but since there were no night fighters operating in this area, this latter function had never emerged; in any case the Seeburg Tisch had not been installed, although provision for it had already been made. 10. At the time of the Invasion, the plotting equipment consisted of a ground-glass screen, measuring some 8 x 12 ft. let into a wall, the glass bearing a map on which the plots were drawn. In addition to this a small-scale map of Northern France, overlaid with tracing paper, was laid flat on a table but this latter had never been put into use, having been forestalled by the Invasion. 11. In operation, plots from the Würzburgs and Freya were made in pencil, no distinction being made on the ground-glass screen between friendly and enemy plots. 12. The plotters, who wore earphones, received their information direct from the operators of the Freya or Würzburg, and transferred their plots to the ground-glass screen. A man called an "Ableser" then read off the plot from the ground-glass screen and telephoned it to Jafü 5 at Bernay, and latterly in the Western suburbs of Paris. 13. At one end of the room there was a platform on which sat a supervisor, who was responsible for the accuracy of the plotted information. He kept his eye on all plotting whilst listening to information as it came from the Radar equipment. He had a small telephone at his side through which he could plug in to any line from Würzburg or Freya. SOME NOTES ON RADAR EQUIPMENT. General Remarks. 14. The only knowledgeable P/W, an officer, gave as his opinion that British and American Radar technique are slightly ahead of their German counterpart. In German Signals circles, he said, it is openly admitted that any piece of Allied radar equipment is seized upon and studiously copied. 15. One major difference, he believed, was that Allied Radar equipment was always smaller and more compact in construction than similar German apparatus. Hand written comment: but the German Rotterdam weighs about half H2S - its British original! 16. Some few details on current German Radar Geräte were given by the above source. These are summarised below. Würzburg. 17. The Würzburg Riese on the station at Douvres were of the usual type, and had a search range of 30/40 kilometres. The frequency of both Würzburg Riese was stated by P/W to be 600 mc/s. "Window". 18. Some operators of the Würzburg and Freyas, although agreeing that they experienced interference from "window", interference which showed itself in a series of specks and lines on the presentation screen, maintain that because "window" travels more slowly than an aircraft, an experienced operator can distinguish the flight of the aircraft against the tracks of the "window". 19. The officer P/W, however, is sceptical about all anti— window devices, and believes that the German Radar authorities are seriously perturbed by it. 20. Some few weeks ago Goering, it is alleged, offered a cash prize of 300,000 Reichmarks to any Signals personnel who could invent an apparatus to outwit "window". Nürnberg Gerät. 21. According to P/W, the Nürnberg Gerät is fitted to Würzburg in order to eliminate the effects of "window". This apparatus has not been entirely successful, although it makes the operator's job slightly easier. "Würzburg Laus". 22. The "Würzburg Laus" is said to be an apparatus replacing the Nürnberg Gerät as a counter measure for "window". The apparatus in contained in a box 18 x 9 x 9 inches, which is attached to the Würzburg. 23. The "Laus" is a much more recent development, and is said to be somewhat more successful than the Nürnberg Gerät. Flanderzaun. 24. This is the colloquial name given to highly characteristic interference pattern on the screen of the Würzburg and Freya. The word is apparently associated with the barbed wire entanglements of Flanders in the last war, and this gives some indication of the picture which the interference makes. 25. P/W believed that this interference is a transmission apparently on the frequency on which Würzburg and Freya are operating, and same P/W have the idea that it emanates from the Isle of Wight vicinity. Köthen Gerät. 26. The "Köthen Gerät" is, according to P/W, not an apparatus but a frequency of the Freya. For example, particular frequencies on Freya are designated A, B, C and D, and Köthen is merely another frequency deriving its name from an experimental station at Köthen. 27. The A, B, C and D frequencies, P/W thinks, were produced by civil firms, and the Köthen name implies that this frequency is a development of the Luftwaffe's own experimental station at Köthen. "Limbach". 28. Amongst documents found at the Radar station at Douvres was a paper headed "Limbach"; this piece of apparatus was stated to be attached to the V.H.F. transmitter/receiver in the aircraft and to operate in conjunction with the Freya on the ground. 29. The paper stated that the procedure employed with this apparatus was similar to that of the Gemse - Erstlings procedure, but strangely enough was used in conjunction with the FuGe 7. 30. According to this P/W, the Limbach was superseded by the Gemse - Erstling (FuGe.25). 31. The document in question has been forwarded to A.D.I.(Sc). Rammstoss Gerät. 32. This is stated to be an instrument carried in German bombers, its purpose being to show the position of other aircraft and prevent collisions in tight formation. Rotterdam Gerät and Panorama Gerät. 33. It is stated that both these instruments, Allied in origin, are now being used by G.A.F. aircraft, but all P/W had heard was that the Panorama Gerät had a wide focus, whilst the Rotterdam Gerät was designed to show a small area. Diana. 34. At long last, after a lapse of 21/2 years, confirmation of "Diana" has come to light through documents. The first mention was from a notebook of a P/W of I/K.G.30 in August 1941 (A.D.I.(K) 420/1941), which stated that Diana was to be similar in principle to Elektra, but working on a short-wave band and within a frequency range of 3,000/6,000 kc/s. 35. The present document notes that "Diana" is similar to Elektra but operates on short waves. This P/W stated that "Diana" had not been operational. ORDER OF BATTLE - LN. REGIMENT 53. 36. The 53rd Ln. Regiment, to which the 8th Kompanie at Douvres belonged, consists of a number of Kompanien ranging from 1 to 26; The Kompanien are not necessarily numbered consecutively, so that the total in the 53rd Ln. Regiment may therefore be less than 26. All the Kompanien had code names. 37. The 53rd Ln. Regiment was responsible for an area bounded on one side by the coast, and on the other sides by a line running from the tip of the Cherbourg peninsula to the South of Paris and northwards to Dieppe. Its Kompanien lie all along the coast and towards the interior at a distance of 30/40 km. apart; each Kompanie's area overlaps so that the entire territory is completely covered. 38. The H.Q. of the 53rd Regiment is in Paris and is under the command of Oberstleutnant FLECH, with Major HOFFMANN as Deputy. 25th Kompanie. 39. The 25th Kompanie is the H.Q. Kompanie and has a strength of 20/25 men, who were engaged in visiting Freya and Würzburg sites of the Regiment and doing minor repairs. It was stated that these men were by no means skilled engineers, and knew nothing of the internal workings of the Freyas and Würzburgs. 8th Kompanie. 40. The 8th Kompanie at Douvres had a total strength of 160 men, who were divided as follows:- Kompanie Stab............ Administrative Staff. Zug 1 ) Zug 2 ) ................. Personnel manning the Freya and Würzburg on six-hour shifts day and night. Flak Zug................. Personnel manning and guarding Flak position round the Kompanie’s site. 41. Another Kompanie of this Regiment, the number of which was unknown to these present P/W, was said to be manning a site at St. Valery-en-Caux. MORALE. 42. Generally speaking, the morale of the 8th Kompanie during the pre-Invasion raids was high, and their resistance during the final attack on the station was certainly not suggestive of low morale. It is noteworthy, however, that since capture and the absence of the excitement of action, these P/W are heartily glad to be out of the war. The majority are convinced that Germany has already lost the war. SEE APPENDIX OVERLEAF. A.D.I.(K). S.D. Felkin, 30 June 1944 Wing Commander 1. The Deputy Commander of the 8th Kompanie at Douvres an Oberleutnant - was good enough to bring his paybook with him, and his career is therefore set out below as a matter of interest. Oct. 1937 – March 1938... Was with Ln. Abteilung R.L.M., 2nd. Komp. at Potsdam (This was, supposed to be one of the very elite schools for Signals in Germany before the war). March 1938 – April 1938.. Was with Ln. Abt. R.L.M. 2nd. Komp. in Vienna, and took part in the Anschluss. April 1938 - Aug. 1938... Back to the R.L.M. 2nd. Komp. at Potsdam. Aug. 1938 - Sept. 1939... Acted as Funker to Ln. Regt. 4, 7th Komp. in Vienna. Sept. 1939 - Feb. 1940... Became a Horchfunker with Ln. Regt. 4, 7th Komp. At Cracow. Feb. 1940 - March 1940... Was posted to the Ln. Officers' Training School at Halle. April 1940 - Aug. 1940... Joined Ln. Regt. 4, Abt. III as Staff Officer. Here he was in command of a Hörstelle. Aug. 1940 - April 1941... Became O.C. of Horchstelle (W.24) at Breslau. (P/W explained that all these Hörstellen are described in passon and paybook as Wetter Funkempfangstelle which is in fact only a cover name for Horchdienst). April 1941 – March 1942.. Was at the depot of Horchstelle (W.3) which is at Athens. Here his job was to listen in to English ground telegraphic messages which were coded and decoded. March 1942 - April 1942.. Posted to Nikolaiew in Russia as Staff Officer to III Abteilung Ln. Regt. 4. April 1942 - May 1943.... Served in Ln. Regt. 130, who were there in the South Russian sector in support of a Flak division. May 1943 - May 1944...... Became O.C. of the 11th Komp. Of Ln. Regt. 57 and later O.C. of the 7th Komp. Of the same Regiment then near Orleans. 2. In May 1944 he was posted to his present unit (Ln.53, 8th Komp.) as Second-in-Command to Hauptman EGLE. He says that it was intended that he should take over this Company in a very few weeks' time. Decorations: Erinnerungsmedaille for Austria. Erinnerungsmedaille for Sudetenland. K.V.K. Second Class with Swords. Rumanian Cross given to those who fought against Communism. Krimm Shield, which commemorates the battles of the Crimea, including Sebastopol and Kersch and last:- E.K.II. |
GERMAN KNOWNLEDGE OF 'OBOE'
SECRET A. D. I. (K) Report No. 318/1944
THE FOLLOWING INFORMATION HAS BEEN OBTAINED FROM P/W AS THE STATEMENTS HAVE NOT AS YET BEEN VERIFIED, NO MENTION OF THEM SHOULD BE MADE IN INTELLIGENCE SUMMARIES OF COMMANDS OR LOWER FORMATIONS, NOR SHOULD THEY BE ACCEPTED UNTIL COMMENTED ON AIR MINISTRY INTELLIGENCE SUMMARIES OR SPECIAL COMMUNICATIONS. GERMAN KNOWNLEDGE OF 'OBOE'. 1. Attached is a translation of a paper issued by the General der Flakwaffe on 24th May 1944 concerning the British 'Oboe' procedure - called by the Germans the Boomerang. 2. Apart from showing that the enemy understands the working of 'Oboe' the report is of interest as it indicates the lines on which German defence was concentrating. Night-fighters are dismissed summarily and the main hope is that, by knowing the approach course, the height and the speed of the attacking aircraft, the Flak defences must be concentrated near the bomb release point so as to produce a "Vernichtungsfeuer" by which success was certain. The report also hints that, since the German knew the 'Oboe' frequencies, radio counter-measures were in hand. 3. One other point of interest is the high standard of the plots of aircraft attacking on the night of 2nd February 1944. This Sketch of is reproduced as Appendix II. 4. The original document has been passed to A.D.I.(Science). A.D.I.(K) S.D. FELKIN 29 June 44. Wing Commander TRANSLATION SECRET ("TOP SECRET") Oberkommando der Luftwaffe Bernau b/Berlin d.24.5.1944 Tel.: Berlin 56 40 76 App.:122 General der Flakwaffe Bernau 814 u.815 od.üb. (General der Flakausbildung) L.V. 12. Az. 79 m Nr.0236/44 g.Kdos.(A/C) Number of Copies: 250. Copy N°: 79. Subject: Combating "Boomerang" Aircraft. Attached are instructions for dealing with aircraft attacks using the Boomerang procedure. In view of the importance of defence against this new method of attack adopted by the enemy it is imperative that all units be instructed in the Boomerang procedure and that counter—measures are adopted on the lines laid down in the attached instruction. Subsequent observations and experiences are to be reported to the General in charge of A.A. defences. Distribution: All independent Flak Groups as well as interested sections of O.K.L., O.K.H., O.K.M., SS-Führungs-Hpt.-Amt, Höhere Kdre., Flakersatzdivision General der Jagdflieger, Generalnachrichtenführer, General d. Kampfflieger u. GL/Flaktechnisches Amt. (Sgd) v. Axthelm. Generalleutnant. TRANSLATION SECRET ("TOP SECRET") Encl. To: OKL – Gen.d.Flakwaffe (Gen.d.Flak-ausb.) Nr.0236/44 g.Kos. (A/C) Dated 24/May/44. A. General. Recently, nuisance raids have been developing more and more into high altitude precision attacks against pin-pointed targets (particularly important industrial complexes) by means of a special navigational procedure known as the "Boomerang" procedure. So far, "Boomerang" attacks have only taken place at night on the Rhine-Westphalian industrial area, Aachen and Osnabrück, airfields and railway stations, in the area of Luftgau Belgium/N. France, Paris and targets in Brittany. The "Boomerang" aircraft employed were Mosquitoes belong to 105 and 109 (B) squadrons, stationed at Marham. Immediately after take-off the aircraft climb to the prescribed attacking height of 8,000 to 11,000 metres, with a view to checking wind drift. The enemy is carrying out on an increasing scale his precision attacks and pathfinder technique using the "Boomerang" procedure. It is clear from the increase of activity that the enemy is constantly expanding his "Boomerang" organisation and improving the technique. An expansion of these attacks on further targets with ever increasing effect is the result. It is therefore essential to bring to bear everything in our power with a view to combating "Boomerang" aircraft. The basic principle is that aircraft must be shot down. B. The "Boomerang" procedure. The "Boomerang" procedure is the most accurate method of remote control at present known. It consists of controlling aircraft by means of Radar stations located in S., S.E. and E. England. These stations work together in pairs of which one is the main station, and passes navigational signals to the aircraft. One signal from this station indicates the course to the pilot whilst the other is for the bomb-aimer to release the bombs. (see App. 1). The aircraft to be controlled flies under its own control to an agreed point, where the remote control takes over. The aircraft is then directed by W/T to the turning point, which is on an arc centred on the Radar station in England and passing through the bomb dropping point. Constant corrections from the ground station in England keep the aircraft on its course (see App. 1) but in spite of the great accuracy of measurement deviations up to 300 metres are possible. The total time required for the target approach is 8 to 15 minutes. As soon as an aircraft passes over the target, the next one is taken over by control. The time interval between attacking aircraft is frequently reduced by attaching several uncontrolled aircraft to one controlled aircraft, or by using further pairs of Radar stations. The uncontrolled aircraft aim their bombes on ground or air markers. The approach to targets East of England is made from a N. - S., S. - N. or S. – W. direction. Targets South of England are approached W. - E. or E. - W. The course depends upon the relationship of the two Radar stations to one another. Unless there in a disturbance by a jamming station the final phase of the line of approach becomes an arc centred on the ground control station in England and passing through the objective to be attacked. It has been observed that simultaneous flights to different objectives on a N.- S., S.- N. as well as S.- W. and N.- E. courses, have been carried out, which proves that the enemy has already set up several ground stations. The range of this system is limited by the curvature of the earth and for a flight at a height of 9,000 metres, the range is between 400 – 450 km. The bombing accuracy depends on the reading and measuring accuracy of the ground station in England. The accuracy is within a square of approximately .5 km. by .5 km. So far, the followings types of "Boomerang" attacks have been made:- a) Single "Boomerang" aircraft. b) One "Boomerang" aircraft followed by 2-5 uncontrolled aircraft. c) "Boomerang" aircraft as Pathfinders for a following bomber force. d) "Boomerang" Pathfinders as decoy marker flaredroppers and "window" aircraft. (Translator's note: the German text is ambiguous. The word is "Scheinmarkierer" which may mean decoy or illuminating markers. The subsequent context suggests the former). The "Boomerang" Pathfinders at first saturate the approach and target area with "Window", then place light markers over the target. The bomber stream then follows up immediately on the "Boomerang" course. C. Counter-measures. The following take part in "anti-Boomerang" attacks: a) Night fighters. b) Radio jamming service c) Flak. I. Our own Mosquito night-fighters (sic) have not had any worth-while successes in shooting aircraft down prior to the bomb release or to the commencement of the Pathfinder activity. Over a period of time, however, night-fighters should be more successful, provided high flying aircraft are employed. Uncontrolled night-fighting with the aid of search lights is possible if our own fighters are high enough and in sufficient numbers in the waiting area over the Flak zone. Because of vapour trails, it is possible to pick out highflying aircraft by searchlights. II. The radio jamming service has appreciated the principles of the "Boomerang" system and has set up jamming stations. It is possible to force part of the approaching aircraft off the approach line by jamming. However, the enemy soon recognises the disturbance and can change over to a pre-arranged alternative frequency. The radio jamming service has already met with success, but is still limited in its effectiveness. III. The main burden of defence, now as before, rests with the Flack. For the successful execution of the "Boomerang" system conditions must be fulfilled:- 1. The attack must take place at a constant height of about 8,000 - 11,000 metres. 2. The target approach must follow a fixed course for several minutes. (Course for every objective known). 3. The ground speed must remain constant throughout the approach. (140 - 180 metres/s.) These known and partly constant target factors constitute a great weakness to the enemy. In addition the Mosquito, because of its wooden construction, is highly vulnerable to well-directed Flak. If, in spite of these favourable conditions, the Flak has only so far obtained little success, the fault lies in the increased factor of error when engaging targets at great heights, and also to the high speed of the Mosquito. On the other hand, the courses flown at the moment are well-known. This factor, together with the known target heights and target speed, enable the point of bomb release for each individual objective to be calculated accurately and in advance. These known facts, combined with the total fire-poor of all batteries within reach of the bomb-releasing area, should produce a successful "Vernichtungsfeuer" (annihilation fire) and prevent accurate bombing and lead to aircraft being shot down. D. Methods of Shooting. 1.) The shooting method employed on principal is annihilation fire. 2.) Provided that: a) The course is known, b) The target approach is fixed and confirmed by the Malsi Flak Calculating instrument. c) It is known with certainty that our own radio jamming does not result in the deviation of the enemy aircraft from its course and that the speed and height remain constant. This contradicts L.Dv.400/4b und VER-Flak 18 Ziff.11) 3.) If the precise plotting is difficult, the following measures are to be taken: a) The track is to be set in accordance with the known value. b) The ground speed is to be obtained and passed on by the Flak transmitter. In the absence of this data, action is to be taken on the basis of previous experience. (Translator's note: in other words, use your own brains). c) Height is to be obtained from accurately adjusted Radar and is to be passed over the Flak transmitter. 4.) With reference to the manner, in which "Boomerang" coursers are to be obtained for individual objectives, Commands will contact Luftgaukommando VI with a view to ascertaining the courses for their own particular area. E. Tactical Employment. Suitable steps must be taken in the event of a change in the direction of approach of "Boomerang" aircraft, and if possible one to two batteries (special Eis. batteries) will be brought into the probable direction of approach for immediate action. F. Counter-measures. The following is to be noted when combating "Boomerang" aircraft: 1.) Most accurate alignment of the respective batteries (adjustment of instruments and guns, calibration of direction-finding apparatus, re-checking of ballistic correction of the moment in order to eliminate the meteorological factor). 2.) Blocking together of the movement of target values: a) Set course for known value. b) Determine ground speed and height from previously emplaced batteries over Flak transmitter. 3.) As far as possible the Trupp should be provided with uniform ammunition (as few different batches as possible); calibration shoots should be carried out with this ammunition and muzzle velocity determinations with (?special) calibration ammunition should be avoided. 4.) Accurate meteorological reports must be obtained every two hours for heights up to 11,000 metres. These must be actual and not extrapolated. Contact must be made with the nearest airfield. 5.) Charge temperature should is periodically determined by means the two specially equipped cartridges (Messcartuschen) placed in the ammunition dump. 6.) The ammunition used for checking drill time should be carefully controlled and the error should be eliminated. 7.) Preliminary practices should be made along the known lines of approach by means of special fire control tables prepared for this purpose. Test shoots should be carried out using intervals of one second. (FAS I will supply fire control tables for "Boomerang"). 8.) All actual "Boomerang" courses should be charted on the Malsi plotting table as a check against the actual plots. (See Appendix II). A systematic research of shooting at great heights, having due regard to the available ammunition has been inaugurated. Results are to be expected shortly and until then all existing orders and instructions hold good. In order to keep counter measures apace with the enemy's intentions, it is essential to inform higher quarters of any new observations made during "Boomerang" attacks. The Luftgaukommando and Divisions are instructed to report regularly their experiences of "Boomerang" counter-measures to the General der Flakwaffe. |
Northern Convoy Routes
SECRET A. D. I. (K) Report No. 410/1945
THE FOLLOWING INFORMATION HAS BEEN OBTAINED FROM P/W AS THE STATEMENTS HAVE NOT AS YET BEEN VERIFIED, NO MENTION OF THEM SHOULD BE MADE IN INTELLIGENCE SUMMARIES OF COMMANDS OR LOWER FORMATIONS, NOR SHOULD THEY BE ACCEPTED UNTIL COMMENTED ON AIR MINISTRY INTELLIGENCE SUMMARIES OR SPECIAL COMMUNICATIONS. G.A.F.SIGNALS INTELLIGENCE IN THE WAR — IX Norway and the Northern Convoy Routes. 1. In this series dealing with various aspects of the G.A.F. Signals Intelligence service in the war, it had been intended to conclude with the eighth report. Since the issue of the first report, however, another P/W has become available who had a comprehensive knowledge of signals activities in the Norwegian area throughout the war. It has therefore been found possible to add the present report, the ninth and final in the series. 2. The gradual expansion of signals intelligence based in Norway, and the Allied activities which it covered, are followed in this account from year to year from the time of the invasion of Norway onwards. In order that ready comparisons of the extent of that expansion may be made each year is dealt with separately, and maps showing the situation at various intervals during the war are appended. 1940. NUCLEUS OF THE ORGANISATION. 3. Soon after the invasion of Norway in May 1940, signals intelligence personnel from W-22 at Husum were formed into a new unit and sent to operate at Oslo. This new unit was named W—Leit 5 and, subordinated to the Höherer Nafü of Luftflotte 5, formed the nucleus of the projected signals intelligence service in Norway; its initial strength was that of a Trupp, but by the autumn was to be increased to a Zug (platoon). 4. The function of W—Leit 5 was to act as the central organisation in Norway for the comprehensive monitoring and evaluation of all enemy R/T and W/T traffic in the North Sea area, and the watching of R.A.F. Coastal Command operations against the West coast of Norway. Information was to be passed to the higher signals intelligence authorities in Germany, who in return fed WLeit 5 with such data on Bomber Command radio traffic as was of value to the Norwegian area. The unit did not itself undertake interception work, but confined its activity to organising the various intercept units and evaluating their results. 5. The first intercept unit, W-25, was set up at Trondheim, Skatval at the end of May with the strength of a Trupp, and also operated a H/F Adcock D/F set on Örlandet. This unit covered W/T traffic of 18 Group Coastal Command and W/T and R/T traffic from aircraft carriers, its intercept results being passed to W-Leit 5 at Oslo. 6. At the same time, W-25 was to make a local evaluation of its intercepted signals and pass the results to a specially appointed signals intelligence officer attached to Fliegerkorps X, so that the latter could amplify its air situation picture. Actually the greater part of the material passed by W-25 to the Fliegerkorps consisted of intercepts from reconnaissance aircraft of 18 Group. 7. At the end of August, W-25 was moved from Skatval to Stavanger, partly owing to the concentration of 18 Group's attention to that part of Norway and partly in order to be near Fliegerkorps X headquarters, which had meanwhile moved to Stavanger. 8. At the beginning of July another intercept Kompanie, 9/Ln. Regt. 2, had moved into Norway and had been put into operation at Naerland, near Stavanger. This unit employed an Adcock D/F station, whilst rhomboid intercept installations were planned and partly constructed during the latter part of the summer. 9. 9/Ln. Regt. 2 was to intercept the W/T traffic of 15 and 18 Groups and the H.F. R/T traffic of the fighters operating in the North of the U.K.; parallel with W-25 at Stavanger, this unit was to pass its intercept results to W-Leit 5 at Oslo and at the same time to make a local evaluation for the benefit of Fliegerkorps X. 10. In October the Signals Intelligence service in Norway began to take shape with the formation of an Abteilung, III/Ln. Regt. 5, subordinated to the Höhere Nafü of Luftflotte 5 both operationally and in its organisation. In December, 9/Ln. Regt. 2 at Naerland was renamed 9/Ln. Regt. 5. 11. The listening chain was completed by the subordination of W-22 at Husum (Schleswig Holstein) to III/Ln. Regt. 5. The duties of W-22 were essentially the same as those of W-25 and 9/Ln. Regt. 5, namely to feed W-Leit 5 with the results of its observations. 12. Owing to the lack of adequate D/F equipment in Norway at this time, and in order to ensure a full cover of Coastal Command operations, Husum also had to monitor 15 and 18 Group traffic. In addition, it shared with 9/Ln. Regt. 5 the task of covering the schools and ground networks of Coastal Command. 13. Once the full interception equipment of 9/Ln. Regt. 5 had come into operation at Naerland, W-Leit 5 was able to fulfil its primary tasks of controlling the coverage of the intercept station, evaluating the intercept results collected from the outstations by teleprinter tie-lines and distributing the resulting intelligence to all interested commands and units. 14. A situation report compiled from current messages and documents was produced each day, and every fourteen days a consolidated report was issued containing the more long term intelligence on strength and locations of enemy units, types of aircraft and tactics, and the identities of units being employed on specific operations. 15. Thus, from the late summer of 1940 onwards, intercepts of great value to G.A.F. reconnaissance units were regularly passed to the Operations Staff of Luftflotte 5. All important intelligence was immediately sent to Abteilung I of O.K.L. INTERCEPT ACTIVITIES. 16. Observation of 15 Group radio traffic was essential for providing the G.A.F. reconnaissance and coastal units with a picture of the air situation in that Group's sphere of operations. The watch on 18 Group by W-25 and 9/Ln. Regt 5 aimed at keeping a check on its strength and dispositions. 17. The H.F. R/T traffic of R.A.F. fighters based in the northern U.K. produced intelligence on defence tactics, organisation, strength and dispositions. This particular listening activity was supplemented by the D-Funker (interpreter radio operators), carried in aircraft of the long-range reconnaissance units for the purpose of evading attack by Allied fighters. When in April 1941, R.A.F. fighters converted to V.H.F. this practice was discontinued. In the late autumn of 1940 the 0.T.U.'s in Scotland and the Midlands were also covered. 18. Beacons in Scotland and the Midlands were covered by 9/Ln. Regt. 5 at Naerland from 1940 until the end of 1943. This work was controlled partly by W-10 (later the Leitstelle der Funkaufklärung) in Germany and partly by the Höherer Nafü of Luftflotte 5 for the benefit of G.A.F. units operating from Norway. The Kompanie supplied such information as it had collected on location, recognition signals, signals strength and method of operation of the beacons, and was frequently called upon by Luftflotte 5 to suggest uses to which such beacons could be put for the benefit of the G.A.F. 19. Meteorological traffic was also covered by 9/Ln. Regt. 5, and intercepted messages were passed to the interested G.A.F. Met. stations in the Norwegian theatre and to W-22 at Husum for further distribution amongst stations in Germany. 20. Responsibility for breaking the Syko messages of Coastal Command reconnaissance aircraft lay with W-22 at Husum, and for this purpose traffic of 16 and 19 Groups and other networks were also intercepted in order to increase cryptographic depth. This traffic could not be broken with sufficient speed to be of tactical value, but it provided long-term intelligence on types, squadrons, dispositions, operational methods, distress signals and accidents. Results were forwarded in collated form to interested units on day plus one. 21. In the succeeding years W-22 was called upon to an increasing extent to cover various R.A.F. and U.S.A.A.F. formations. The breaking of other types of codes and cyphers was undertaken centrally by W-10. 1941. EXPANSION OF SIGNALS INTELLIGENT. 22. In April 1941 R.A.F. fighter units in the North of England discontinued the use of H.F. R/T and converted to V.H.F., thus robbing German signals intelligence of a fruitful source of intelligence. From early summer, therefore, arrangements were made to experiment on the West coast of Norway with V.H.F. receivers and various types of aerial arrays; in the autumn V.H.F. experimental flights were carried out in the direction of the East Coast of Scotland with an aircraft specially provided by O.K.L., but results were disappointing. 23. By the summer, intercept equipment in use in Norway comprised 1 L.F. and 3 H.F. Adcocks as well as 5 interceptrhomboid installations. The function of the latter was to D/F ground transmissions with low signal strength, as well as the traffic of 15 or 18 Group aircraft operating at extreme ranges from the intercept stations. 24. The three H.F. Adcock stations were employed respectively for 15 Group, 18 Group and other radio traffic from unknown ground stations; the L.F. Adcock covered Coastal Command reconnaissance traffic, beacons and all other traffic from unknown ground stations. 25. In the autumn another radio interception Trupp, Wo-Hammerfest, commenced operations. This unit was to test reception conditions in northern latitudes for the purpose of covering bases in Iceland and the traffic of Allied long-range reconnaissance aircraft. The unit met with many difficulties, amongst which were the extreme remoteness of the unit and consequently poor communications and 1ack of D/F equipment. Reception conditions proved unreliable on account of atmospherics. By the end of 1941 no solid results had been achieved. 26. In the meantime the organisation of signal intelligence in Norway was being developed. A signals intelligence officer was attached to the operations staff of Luftflotte 5; by the end of the year all signals intelligence units in Norway were subordinated to the Höherer Nafü Luftflotte 5, and all came under the administrative command of Ln. Regt. 5. 27. During this year the channels of communication of W-Leit 5 at Oslo were improved and at the close of the year comprised teleprinter lines to Berlin, Husum, Naerland, the G.A.F. exchange at Oslo and between Naerland and Husum. Direct telephone lines were also installed to Luftgau Norway and the Naval Command at Oslo. 1942. D/F BASE ATLANTIC. 28. The most notable development in signals intelligence in Norway during 1942 was the establishment in the summer and the preliminary organisation of a chain of intercept stations, known as D/F Base Atlantic, for the covering of Atlantic signals traffic. This chain was to comprise stations at Bodö, Örlandet, Naerland, Husum (Germany) and Brest, with Naerland as the central point. 29. The D/F Base Atlantic did not begin operations as an entity until the early summer of 1943, but its main functions were to supply an increased number of plots on 15 Group aircraft on convoy escort, end to watch the anti U-boat flying boats. V.H.F. TRAFFIC. 30. The experiments in V.H.F. interception begun during 1941 were continued but with little success. Various types of antennae were tried at different locations, and the special aircraft continued spasmodic flights towards the East Coast of Scotland, mainly to test antennae and to check up on new kinds of transmissions. CONVOY TRAFFIC. 31. During the autumn it was decided that the interception Trupp, Wo-Hammerfest, was serving no useful purpose. 32. The interception Trupp established at Hammerfest during 1941 had supplied useful data on reception conditions in Northern Norway, but as far as operational results were concerned, no useful purpose was being served and the unit was withdrawn. Shortly afterwards, however, another similar unit began to operate at Svanvik. 33. Conditions for operation at Svanvik were found to be more favourable than at Hammerfest, besides which, the former station was provided with a D/F Adcock, and during the autumn the Trupp was busy with traffic from the two Allied convoys, P.Q.18 and 19. 34. From this traffic two main facts were elicited. The first was that some of the flying boats had transferred from Sollum Voe to Murmansk, whence they were flying anti U-Boat patrols. The second new fact was that the R/T traffic from land-based or escort carrier fighters could be intercepted and D/F'd.; in this way additional data to those from normal reconnaissance sources could be supplied to supplement the air situation picture. 35. Signals intelligence was particularly valuable in providing security to German naval forces passing along the Norwegian coasts. CHANGES IN ORGANISATION. 36. In the autumn another intercept Kompanie, the 8th, was added to III/Ln. Regt. 5. 37. Training of its new personnel began towards the end of the year, and its eventual duties were to man the D/F Base Atlantic in Norway, to monitor Allied North Sea convoys and to watch for new British and Russian traffic on the northern front. 38. At the end of the year W-Leit 5 at Oslo was renamed 14/Ln. Regt. 5, whilst W-22 at Husum became 15/Ln. Regt. 2. 39. Communications facilities of 14/Ln. Regt. 5 were further increased during 1942, and at the end of the year consisted of the following:- 1 Teleprinter line to Gefechtsstab of Luftflotten Kdo. 5. 1 Teleprinter line to G.A.F. exchange, Oslo. 1 Teleprinter line to Naerland. 1 Teleprinter line to Husum. 1 Teleprinter line to Berlin. 1 Teleprinter line from Naerland to Husum. 1 Telephone line to G.A.F. exchange, Oslo. 1 Telephone line to Ln. Regt. 5. 40. The teleprinter line between Naerland and Husum which had been established in 1941 was used on occasions for D/F squad traffic, but as the same line had to be used for all other purposes this was not entirely satisfactory. 1943. 8/LN. REGT. 5. 41. The training and expansion of 8/Ln. Regt. 5 continued until the spring, when the 3rd Zug was ready for operations and was sent to Svanvik. Two D/F Adcocks were constructed so that both East and West D/F'ing could he carried on simultaneously. 42. An advance Trupp of the 8th Kompanie was sent to investigate the terrain in the Alta-Bardufoss area with a view of determining a final position for intercept operations. Bardufoss was found suitable so far as convenience and communications were concerned, and two Züge of the Kompanie soon followed. 43. Intercept Trupps of 8/Ln. Regt. 5, with D/F sets at Svanvik, Bodö and Örlandet, were put to covering all Allied W/T and R/T traffic in the North Sea and from Iceland Base and North Sea convoys. The Kompanie was also commissioned by W-10 to intercept all U.S. traffic, the results of which were to be transmitted to W-10 direct and without preliminary evaluation. 44. At times the Kompanie produced excellent results, especially in the interception of unknown U.S. traffic, but operations in general suffered from frequent atmospheric disturbances and a lack of any results which had value for immediate operations. 45. The Zug at Svanvik enjoyed far more favourable conditions than the unit at Bardufoss; besides the valuable work which it performed in following North Sea convoys it investigated radio conditions in the northern area. Its assistance and advice were sought for important tactical operations in the area. D/F BASE ATLANTIC. 46. As already stated, the main function of the D/F Base Atlantic was to D/F or plot aircraft of 15 and 18 Groups, with a secondary function of D/F'ing unknown radio stations. 47. Inadequate communications between Oslo and Brest, however, made the immediate use of the information from Brest impossible, its only advantage being in its value for subsequent confirmation. 48. On the whole, the Base proved its worth as it supplied Fliegerführer Atlantik and B.d.U. with regular intelligence on strength, tactics and area of operation of convey escorts and of the aircraft of 15 Group, besides, providing B.d.U. with data which often led to successful U-boat attacks. 49. During the year the communication facilities of the Örlandet, Bodö and Svanvik D/F sites remained unsatisfactory, but nevertheless they contrived to make valuable contributions to the intelligence picture. ANGLO-SWEDISH COURRIER SERVICE. 50. In the course of the year an intercept cover was put on the Anglo-Swedish courier service, and the monitoring was developed to such an extent that daily reports on numbers of aircraft operating, bases and, towards the end of the following year, the squadron strength. TRANSATLANTIC FERRY SERVICE. 51. In the spring, W-10 ordered Husum to undertake the interception of all Allied transatlantic ferry traffic in the North and East Atlantic; the results were to be evaluated by 14/Ln. Regt. 5 at Oslo. The object was to establish the approximate daily figures of aircraft ferried, their density on the various stretches of the outward and return flights, and the types of aircraft employed for varying purposes. 52. Results were teleprinted daily and also distributed in monthly reports. SYKO AND A.R.C. MESSAGES. 53. The breaking of Syko messages was carried out by 15/Ln. Regt. 2 at Husum until Syko was dropped in the middle of 1943. When A.R.C. was introduced considerable initial difficulties were encountered, but by the end of the year some measure of success was achieved and was further increased during 1944. These results were used strategically but never tactically. IMPROVEMENTS IN COMMUNICATIONS. 54. In the course of the year the Kompanien at Oslo, Naerland and Bardufoss were equipped with transmitters in case of breakdown in landline communication. 15/Ln. Regt. 2 became the relay station for the re-transmission of messages to superior and related signals intelligence units in the Reich. 1944. RE-ORGANISATION. 55. The year saw considerable changes in the G.A.F. SignalsIntelligence service as a whole in its attempt to create a homogeneousorganisation. The units in Norway brought into the scheme were renamedas follows:- 14/Ln. Regt. 5 became 1/Ln. Abt. 355. 8/Ln. Regt. 5 became 2/Ln. Abt. 355. 9/Ln. Regt. 5 became 3/Ln. Abt. 355. 15/Ln. Regt. 2 became 5/Ln. Abt. 357. 56. At the same time W-10, the controlling station in the Reich, was renamed Leitstelle der Funkaufklärung. 57. As an anti-invasion measure a mobile listening Zug was created, consisting of a contingent of W/T and R/T operators and evaluators. The unit was responsible to the Fliegerführer and was to be ready to operate at the focal point of an invasion attempt. MOVEMENTS OF UNITS. 58. The intercept station set up during 1943 at Bardufoss and manned by 8/Ln. Regt. 5 (2/Ln. Abt. 355) had shown only partially satisfactory results due to bad reception conditions. The changing war situation made the station redundant as the unit at Svanvik was sufficient for the Northern area so that in the spring the Bardufoss station was moved to Halden. 59. At the same time 15/Ln. Regt. 2 (5/Ln. Abt. 357) was becoming monopolised by the Leitstelle der Funkaufklärung for duties in defence of the Reich, and consequently became of less value to signals intelligence in Norway. 60. After the Allied invasion in France the D/F Base Atlantic suffered the loss of its left wing at Brest and then the loss of the Svanvik base through the evacuation of Northern Norway. In the course of 1944 the entire strategic evaluation of Coastal Command traffic was taken over by the evaluation Kompanie of the Leitstelle der Funkaufklärung which was supplied with intercept data by 5/357 at Husum. V.H.F. AND H.F. INTERCEPTION. 61. The experiments which had been made during 1941 and 1942 with the object of intercepting Allied V.H.F. traffic were finally abandoned in 1944, although the increasing weight of 16 and 18 Group attacks made the use of V.H.F. receivers on the West coast more necessary than ever. 62. Changes which took place in the W/T traffic of 18 Group during 1944 caused some difficulties to the Germans, but on the other hand the combined use of R/T and W/T by Allied forces approaching the Norwegian coasts restored the possibility of obtaining vital intelligence. 63. In such cases as the latter, the W/T intercepts could not be used for direct fighter control but a running commentary on events could be passed to the fighter control officer, detailing direction, probable intentions, tactics and strength. 64. During the year, 2/Ln. Abt. 355 at Halden was engaged in such tasks as covering U.S. W/T traffic and R.A.F. Bomber Command tactics for the benefit of O.K.L. W/T traffic of T.A.F. aircraft was also covered for practice, and 16 Group was intercepted when it operated against the South Coast of Norway. The Kompanie later covered training and part of the coastal network, as well as D/F’ing minelaying and supply dropping activity in the Norwegian area. 65. After the re-organisation of the G.A.F. signals service early in 1944, the radio command stations (Funkbefehlsstellen) established at the divisional and sector reporting centres for the use of the radio observation and jamming services were also used by the Signals Intelligence units for the relaying of messages to higher authorities. At the same time efforts were made to develop the tactical evaluation organisation to the utmost; to that end a close co-operation with radio observation (Fu.m.B.), aircraft reporting and jamming services was achieved. 66. The monitoring of fighter O.T.U.'s in the U.K., which had continued since 1940, came to an end in the spring of 1944 when those units converted to V.H.F. At the same time a fuller cover was put on long range reconnaissance training traffic which was closely connected with the increasingly important North Sea convoy traffic. 67. The latter traffic provided intelligence on tactics, state of development, strength in carrier aircraft and the nature of carrier manoeuvres. To deal with the increase in this convoy traffic a liaison officer was attached to Fliegerführer 5 at Bardufoss and an R/T intercept Trupp was established at Tromsö; R/T operators had already been posted to the D/F squads established at Bodö and Örlandet for the purpose of intercepting R/T traffic of carrier aircraft. 1945. D/F SQUAD TRAFFIC. 68. The radio D/F squad traffic (Funk-Peilkommandoverkehr) instituted at the beginning of the year proved more and more important for assisting the evaluation of 18 Group and Northern convoy traffic and produced invaluable results. An H/F Adcock was set up at Jessheim to supplement the Halden Kompanie's efforts in monitoring Allied Air operations in the Skagerrak, Kattegat and Oslo Fjord and act as alternative D/F base to that at Naerland. A.D.I.(K) and S. D. Felkin U.S. Air Interrogation. Group Captain. 14th November 1945. |
German countermeasures against allied radar jamming
SECRET A. D. I. (K) Report No. 356/1944
THE FOLLOWING INFORMATION HAS BEEN OBTAINED FROM P/W AS THE STATEMENTS HAVE NOT AS YET BEEN VERIFIED, NO MENTION OF THEM SHOULD BE MADE IN INTELLIGENCE SUMMARIES OF COMMANDS OR LOWER FORMATIONS, NOR SHOULD THEY BE ACCEPTED UNTIL COMMENTED ON AIR MINISTRY INTELLIGENCE SUMMARIES OR SPECIAL COMMUNICATIONS. GERMAN COUNTERMEASURES AGAINST ALLIED RADAR JAMMING. 1. The following information, which is believed to be fully reliable, has been obtained in the main from a P/W who had been in charge of Flak Würzburg positions on the Cherbourg Peninsula. 2. Interrogation has been carried out in co-operation with A.D.I.(Sc), but this report deals only with the general principals involved, technical details of circuits and instruments having been passed to A.D.I.(Sc). 3. Ever since the summer of 1942, the Germans have been alive to the possibility of electrical jamming of ground radar, and have had countermeasures under consideration. In the autumn of 1942, amongst other measures, instructions were issued to units using the Würzburg-D to remove the revolving dipole if electrical jamming were encountered, and to replace it with the fixed type dipole aerial from the Würzburg-A. 4. In January or February 1943, instructions were issued which stated categorically that electrical jamming was expected shortly to begin, and detailing countermeasures called by the code names "Stendal A" and "Stendal B", the latter employing a modification to the set known as "Goldammer"; these proved reasonably satisfactory. 5. The use of "Window" took the Germans completely by surprise and was at first almost 100% effective. No countermeasures were available and entire Flak batteries were put out of action. At first the Radar operators were told that they must somehow learn to distinguish the bomber formations from the "Window" reflections, but in practice it was found that only the most experienced operators were able to do this, and then only occasionally. 6. Countermeasures were evolved and introduced fairly quickly, and these are detailed below. All Würzburg instruments in the Cherbourg Peninsula are stated to have been equipped with the necessary modifications at the time of the invasion. 7. The German authorities maintain that these countermeasures are 80% effective, but the present P/W considers that 50% would be a more accurate figure, since one or other of the special modifications to the Würzburg is frequently used. Another point mentioned was that even these special modifications were apt to fail, or at least to prove unsatisfactory, if "Window" was used in very large quantities. 8. Since the introduction of these new countermeasures, the Stendal procedures have become obsolete and are no longer used. NÜRNBERG PROCEDURE. 9. The Nürnberg procedure is a countermeasure against "Window” invented by Stabsingr. HOFFMANN of Flak Artillerie Schule III at Heiligensee. 10. With this procedure, the Würzburg is modified so that variations of signal strength due to rotation of the enemy aircraft's propellers make a note which is audible in the headphone, thus enabling the operators to distinguish between the aircraft and “Window". 11. An improved version of Nürnberg, known as Nürnberg 7, which is less fatiguing to the operators, has also been developed. WÜRZLAUS PROCEDURE 12. This enabled operators to distinguish between fast and slow moving echoes, and so permits differentiation between aircraft and "Window" or permanent echoes. 13. The blip on the Cathode ray tube appears as a blob of light resembling a louse, extending over both sides of the time-base. NOTE:- Captured wax stencils of the original German instructions for the use of the Nürnberg and Würzlaus procedures were received from Normandy after the above interrogation had been completed, and fully confirm P/W’s statements. The stencils have been rolled off, and copies are being sent as an Appendix to this report to A.D.I.(Sc), and to the other departments marked with a star on the distribution. TAUNUS PROCEDURE. 14. This countermeasure to "Window", is achieved by a modification which operates by virtue of the sharper wave front obtained from a true target blip compared with the more gentle sloping of a "Window" blip. P/W stated that this procedure was used in conjunction with Nürnberg and Würzlaus, but was unable to give full details. He claims that Taunus is also effective against jamming by means of noise modulators. FAKIR. 15. Fakir is the term applied when the split presentation both on the bearing and elevation tubes is made to appear on two separate traces placed opposite to each other and nearly a centimetre apart, as shown in the sketch below. 16. This double trace presentation was usual with Würzlaus before the introduction of Taunus; with the introduction of the latter, the use of Fakir has become essential if clear readings are to be obtained on the cathode ray tube. Normal bearing "Fakir" bearing Presentation with presentation with Würzlaus Würzlaus WISMAR PROCEDURE. 17. The Wismar procedure is a counter to electrical jamming, achieved by means of a change of wavelength. 18. For purposes of this procedure the original Würzburg frequency, which this P/W believed to be 600 Mc/s., was separated into two or three bands, each comprising three separate frequencies as follows:- Frequency Al - 3 Mc/s. above A4. Frequency A4 - Original frequency, Frequency A7 - 3 Mc/s. below A4. A second frequency band, Bl, B4 and B7, was also employed, in which B4 was 30 Mc/s. below A4, and B1 and B7 were respectively 3 Mc/s. higher and lower than B4. 19. It was intended that there should be third band "C" below the "B" band, but this has not yet been introduced, as existing transmitters cannot operate so far below the original frequency. 20. A new local oscillator, known as the "Michael Local Oscillator", which is easily tuneable, has been introduced for the Wismar procedure, and nearly all Würzburg-D in the Cherbourg area were equipped with this. WESTERWALD. 21. A captured document, which has been handed to A.D.I.(Sc), gives details of an anti-jamming device known as "Westerwald", which is applicable to Freya and coast-watcher equipment. 22. In effect, this adapts the Taunus technique as used on the Würzburg to Freya and coast-watcher. Westerwald is the name of the mountainous country in Germany just north of the Taunus region. FuGe 25. 23. P/W states, that the Würzburg attachments intended for the FuGe 25 (I.F.F.) procedure have not been fitted for a long time, and that more recently the frames for these have also been removed in the Cherbourg area. He states that the FuGe 25 was formerly called by the code name "ZWILLING". MAINZ AND MANNHEIM. 24. These apparatus, which are developments of the Würzburg, have been reported in A.D.I.(K) 12/1944, paras.18-26, and A.D.I.(K) 141A/1944, paras.24-25. The present P/W refers to them under the numbers 40 and 41 respectively. He states, however, that they are complicated and very expensive, and have hardly been brought into use. A.D.I.(K) S.D. Felkin 16th July, 1944 Wing Commander Anlage 4. Gegenmaßnahmen bei Störung der Funkmessgeräte (Flak) Im Fall von Feindstörung der Funkmessgeräte (Flak) sind sofort je nach Art der Störung die Gegenmaßnahmen: "Wismar" Gemäss L.Dv. 400/30 "Standal" Teil I ‐ IV "Goldammer" "Nürnberg" und "Würzlaus" einzuleiten. Bis zum Erscheinen der Vorschriften "Nürnberg" und "Würzlaus" sind diese beiden Verfahren wie folgt anzuwenden: I. Nürnberg A. Begriffsbestimmung Der Sonderbetrieb "Nürnberg" ermöglicht das Suchen und Auffassen von Flugzielen durch Funkmessgerät (Flak) 39 T bei Störung durch Folienabwurf. Das Verfahren beruht darauf, dass die von einem Flugziel reflektierte Energie periodischen Schwankungen unterworfen ist. Diese erzeugen in den Kopfhörern eines Hörzusatzes einen Brummton von 50 ‐ 150 Hz. Die von Folien reflektierte Energie ist unregelmäßigen Schwankungen unterworfen. Diese erzeugen in dem Hörzusatz ein zischendes und fauchendes Geräusch, das sich von dem Brummton der periodischen Schwankungen deutlich unterscheidet. Der Brummton eines Flugzeuges ist nur dann hörbar, wenn das Flugzeug entfernungs‐und winkelmässig ungefähr angemessen ist. Bei genauer Ortung ist der Ton am lautesten (Maximum). Des Verfahren "Nürnberg" ermöglicht also eine akustische Ortung, wenn die gestörten Entfernungsbereiche auf dem Übersichts‐ und Entfernungsfeinmessrohr ein Zielzeichen nicht oder nur undeutlich erkennen lassen. B. Geräte teile und Arbeitsweise des Sonderbetriebes "Nürnberg" Der Hörzusatz "Nürnberg" ist in die D‐Stufe des Richtgerätes eingebaut. Die auf "Nürnberg" umgerüsteten Bausteine tragen auf der Vorderseite ein "N". Auf der Vorderseite des Richtgerätes sind 3 Anschlussbuchsenpaare für die Kopfhörer des B 1, B 2 und B 3 angebracht. Der Sonderzusatz "Nürnberg" ist bei Schalterstellung E + S immer betriebsbereit. Eine Überprüfung der Betriebsbereitschaft ist möglich durch den Tastknopf in der B‐Stufe des Richtgerätes. Das Suchen des Flugziels hat bei stehendem Dipol zu erfolgen, weil der umlaufende Dipol im Hörzusatz ein Geräusch erzeugt, das die Feststellung des Tonmaximums erschwert. Sind nach der akustischen Ortung Zielzeichen auf dem Übersichts‐und Entfernungsmessrohr festzustellen, dann kann der UmlaufdipoI wieder eingeschaltet werden. Blatt 2 zu Anlage 4 In diesem Fall kann die Winkelmessung durch "Sonderbetrieb Winkelmessung" und die Entfernungsmessung durch "Sonderbetrieb Entfernungsmessung" erfolgen. Das Peilverfahren dient lediglich als Hilfsmittel zum Suchen und Auffassen von Flugzielen, ist jedoch zur Ermittlung von Schiessunterlagen nicht geeignet. Eine Erschwerung tritt ferner dadurch ein, das benachbarte Funkmessgeräte (Flak), (vornehmlich Funkmessgeräte (Flak) 41 T) ein starkes Knarren im Hörzusatz erzeugen, wodurch die Hörkennung von Flugzielen erschwert bzw. unmöglich gemacht werden kann. C. Bedienungsanleitung für Senderbetrieb "Nürnberg“. 1.) Überprüfung des Hörzusatzes „Nürnberg“ B 2 legt den Kopfhörer um, schaltet den Umlaufdipol aus und stellt den Drehknopf "Pot" auf "Null". B 1 stellt den Dunkelpunkt auf eine festzeichenfreie Stelle des Entfernungsbereiches. B 2 dreht an der oberen Schlitzschraube in der D‐Stufe solange nach rechts, bis er ein knatterndes Geräusch hört, dreht dann die Schraube, so weit nach links, bis dieser Ton gerade verschwindet. Drückt auf den Tastknopf auf der rechten Seite des Richtgerätes und ruft, wenn er im Kopfhörer, einen tiefen Brummton hört: "Hörzusatz betriebsbereit! " 2.) Exerzierordnung für die gefechtsmäßige Anwendung des Sonderbetriebes "Nürnberg" Flugziele im Störzeichenbereich nicht feststellbar. Sind Zielzeichen auf den Braunschen Röhren nicht feststellbar, so sind die Winkel ‐und e‐Messung allein nach dem Gehör durchzuführen. Es werden dabei alle drei Werte nach dem akustischen Maximum ermittelt. B 2 ruft bei Auftreten eines Störzeichenbereiches aus: "Feindstörung durch Folien!" Kann er kein Zeichen im Störbereich des Übersichtsrohres erkenne, ruft er nun: "Auffassen nicht möglich!" M.F. befiehlt. "Hörzusatz! " B1 B2 legen Kopfhörer um. B3 B1 dreht am e‐Grobtrieb die Entfernung des Störzeichenbereiches langsam durch, beobachtet die Störzeichen und achtet auf den Ton im Kopfhörer. Hört er neben zischenden und fauchenden Geräusch einen tiefen Brummton, so bringt er diesen am e‐Feintrieb auf in Maximum. Blatt 3 zu Anlage 4 B 2 betätigt gleichzeitig das Höhenrichthandrad und bringt durch Peilen den im Kopfhörer hörbaren Brummton auf größte Lautstärke. Dadurch ist das Ziel grob geortet (Messfehler bei feststehendem Dipol; zur Verwendung als Schiessunterlage nicht geeignet).‐ Das Flugzielzeichen ist noch in dem Störzeichenbereich erkennbar. Der Hörzusatz dient in diesem Fall lediglich als akustisches Hilfsmittel zum eindeutigen Erkennen des Flugziels. Ist dies möglich, kann mit Hilfe des "Sonderbetriebes Winkelmessung“ weitergearbeitet werden. Ist auf Grund der akustischen Ortung auf dem Übersichts‐und e‐Feinmessrohr als Zielzeichen erkannt, rufen B 1 und B2 aus: "Ziel erkannt" M.F. befielt: "Sonderbetrieb Winkelmessung! " B2 schaltet den Umlaufdipol wieder ein. B1 hält das erkannte Zielzeichen auf dem Dunkelpunkt. B2 und B3 messen gemäß "Sonderbetrieb Winkelmessung". Verschwindet das Zielzeichen auf den Röhren kurzzeitig, so führen B1 und B2 bei umlaufendem Dipol das Ziel akustisch weiter bis das Zielzeichen wieder sichtbar ist. II. "Würzlaus". A. Begriffsbestimmung und Erscheinungsform. Das Verfahren "Würzlaus" dient zum Auffassen und Anmessen eines Flugzieles bei Feindstörungen durch Abwurf von Folien. Das Verfahren "Würzlaus" ermöglicht die bildliche Unterscheidung der reflektierten Energie eines sich bewegenden Zieles (Flugzeug) und eines festen Zieles (Düppelwolke). Durch Verwendung eines eingebauten zusätzlichen Hilfssenders wird erreicht, dass sich das Zielzeichen durch eine besondere Formgebung von den Störzeichen unterscheidet. Festzeichen und Metallfolien geben bei Sonderbetrieb "Würzlaus" auf dem Übersichtsrohr sich schlängelnde Zeichen. Die Zielzeichen von einem sich schnell bewegenden Flugziel erscheinen als eiförmige ausgefüllte Zeichen (sogenannte Würzlaus). Auf den Richtrohren erscheinen nach Umschalten auf "Würzlaus" zwei Lichtstriche, auf denen die Ablenk‐und Störzeichen kehrbildlich einander gegenüber stehen. Ein Zielzeichen ist dann genau angerichtet, wenn die beiden, einander gegenüberstehenden Flugzielzeichen (Würzlaus) gleich groß sind. Auf dem e‐Feinmessrohr erscheinen ebenfalls 2 Lichtstriche, aber die Stör‐und Zielzeichen kommen nur auf dem oberen Lichtstrich zur Anzeige. Das Ziel ist dann genau angemessen, wenn der Dunkelpunkt die "Würzlaus" halbiert. Blatt 4 zu Anlage 4 B. Geräteteile zur Bedienung des Sonderbetriebes "Würzlaus". Zum Sonderbetrieb "Würzlaus" sind folgende Geräte und Geräteteile am Funkmessgerät erforderlich: 1.) ein Hilfssender H.S. 62/65 "Michael" (am Ausleger links neben dem Richtsitz) mit Bedienungsknopf "Ankopplung" und Bedienungsknopf "Abstimmung", 2.) ein H.F.‐Kabel vom Hilfssender zum Senderüberlagerer (führt durch den Ausleger in den Sendeempfangsgeräteschrank und ist mit dem H.F.‐Stecker in den Senderüberlagerer eingeführt), 3.)Drehknopf zum Ein‐und Ausschalten der Kehrbildanzeige auf der rechten Seite des Richtgerätes (Mittelteil), 4.) Schlitzschraube (K) zum Nachjustieren des Kreisdurchmessers auf dem Übersichtsrohr auf der rechten Seite des Richtgerätes (Mittelteil), 5.)Senderüberlagerer, die für den Sendebetrieb "Würzlaus" ausgerüstet sind, tragen ein "W" auf der Frontplatte. C. Bedienungsanleitung für Sonderbetrieb "Würzlaus" a. Herstellen der Messbereitschaft. Allgemeines: Das Funkmessgerät 39 T(D) wird nach der L.Dv. 400/8a eingeschaltet und abgestimmt. Mit dem Einschalten des Funkmessgerätes (Flak) ist auch der Hilfssender eingeschaltet. Die Justierung des Dunkelpunktes auf dem Übersichtsrohr entfällt. Die Schraube "Dunkelpunkt" bewirkt lediglich nur eine Verschiebung der Ablenkzeichen auf den Bildröhren. "Abstimmen des Hilfssenders". B1 B2 messen Standziel genau an B3 B2 schaltet Kernbildanzeige ein durch Umlegen des Schaltknopfes im Mittelteil auf der rechten Seite des Richtgerätes von "N" auf "S"; überzeugt sich, daß Bedienungsknopf "Ankopplung" auf Linksanschlag steht regelt Sprühen auf dem Übersichtsrohr auf 2 mm durch Drehknopf "Pot" (Stellung 2 ‐ 3). dreht Bedienungsknopf "Ankopplung" auf Rechtsanschlag stellt Lichtstriche auf dem Seitenrichtrohr (gleichzeitig Höhenrichtrohr) auf größten Abstand durch Drehen am Bedienungsknopf "Abstimmung" am Hilfssender. Blatt 5 zu Anlage 4 Noch B2 bringt Lichtstriche auf 1,5 cm Abstand durch Linksdrehen des Bedienungsknopfes "Ankopplung" justiert Durchmesser des Lichtkreises auf dem Übersichtsrohr nach durch Drehen der Schlitzschraube im Mittelteil auf der rechten Seite des Richtgerätes. Hilfssender ist abgestimmt, wenn Festzeichen als sauberer Schlängel auf den Richtröhren erscheint. B 2 meldet: "Hilfssender abgestimmt". schaltet wieder auf "Normalbetrieb" durch Umlegen des Schaltknopfes im Mittelteil auf der rechten Seite des Richtgerätes von "S" auf "N". schaltet Sonderbetrieb "Würzlaus" aus durch Drehen des Bedienungsknopfes "Ankopplung" auf Linksanschlag. b. Gefechtsmäßige Bedienung. Beachte, dass der Abstand der Lichtstriche im Seitenrichtrohr stets 1,5 cm betragen muss. Durch Änderung der Empfindlichkeit durch den Drehknopf "Pot" ändert sich auch dieser Abstand. Durch Drehen an dem Drehknopf "Ankopplung" am Hilfssender müssen daher Lichtstriche laufend auf 1,5 cm Abstand gehalten werden. B 2 beobachtet das Übersichtsrohr. Bei Feindstörung durch Folien ruft er aus: "Feindstörung Folien" M.F. befielt " Sonderbetrieb "Würzlaus". B 2 schaltet Sonderbetrieb "Würzlaus" ein durch Drehen des Bedienungsknopfes "Ankopplung" auf Rechtsanschlag schaltet Kehrbildanzeige ein durch Umlegen des Schaltknopfes im Mittelteil auf der rechten Seite des Richtgerätes von "S" auf "N". sucht in der vermutlichen Richtung regelt die Empfindlichkeit laufend nach durch Drehen am Drehknopf ''Pot" . bringt Lichtstrich auf normalen Abstand von 1,5 cm durch Bedienungsknopf ''Ankopplung'' am Hilfssender Blatt 6 zu Anlage 4 Noch B 2 beobachtet das Übersichtsrohr. Beim Erkennen einer ''Würzlaus'' ruft er aus: ''Aufgefasst in 130!" B 1 stellt die von B 2 ausgerufene Entfernung durch den e‐Grobtrieb ein hält laufend die ''Würzlaus" auf den Dunkelpunkt durch Drehen am e‐Feintrieb. B 2 u. B 3 messen den Seiten‐ bzw. Höhenwinkel, in dem die beiden kehrbildlichen Würzläuse auf gleicher Größe gehalten werden. Bei genauer Einstellung rufen sie aus: ''Seitenwinkel (Höhenwinkel) ‐ Null 1''. |
RADIO AND RADAR EQUIPMENT: Wilde Sau item 58
SECRET A. D. I. (K) Report No. 357/1945.
THE FOLLOWING INFORMATION HAS BEEN OBTAINED FROM P/W. AS THE STATEMENTS MADE HAVE NOT AS YET BEEN VERIFIED, NO MENTION OF THEM. SHOULD BE MADE IN INTELLIGENCE SUMMARIES OF COMMANDS OR LOWER FORMATIONS, NOR SHOULD THEY BE ACCEPTED AS FACTS UNTIL COMMENTED ON IN AIR MINISTRY INTELLIGENCE SUMMARIES OR SPECIAL COMMUNICATIONS. RADIO AND RADAR EQUIPMENT IN THE LUFTWAFFE - II Navigational Aids. 1. This report is the second of the series dealing with radio and radar equipment in the Luftwaffe. 2. As in the case of the first of the series (A.D.I.(K) 343/1945) dealing with Blind Landing and Airborne Communications Equipment, it is based on interrogation of General Nachrichtenführer MARTINI, Director General of G.A.F. Signals, and a few important members of his staff, and has been supported by a file of current papers which were in the possession of the General’s Chief of Staff. 3. An index of the numerical designations of the navigational equipment mentioned in this report appears in Appendix I. 4. For convenient reference, a translation of the document entitled "Funkausrüstung der Flugzeugmuster, Notprogramm" (signal Equipment in the G.A.F. - Emergency Program) - item 45/99 ff in A.D.I.(K) Documents List 45/9 - which has also appeared as an Appendix to A.D.I.(K) 343/1945, is reproduced as Appendix II to the present report but the list of equipment contained in that document has been omitted as Appendix I gives a fuller list. TRENDS OF DEVELOPMENT. 5. Throughout the course of the war, the general standard of German navigational training was undoubtedly inferior to that of the Allies. A simple form of navigation was taught but navigators track plotted only and relied on W/T aids and in particular positioning by means of loop fixes as the main basis for their navigation. 6. During the early part of the war extensive use was made of Knickebein and other beam systems, but later this form of navigational aid gave way to the "Y" control system (better known by the Allied codeword Benito) and "Egon". 7. Sonne was universally accepted as an outstanding success and from the time of its inception in 1942 research was continuously directed towards overcoming its imperfection, in particular the range limitation. Komet was a typical example, of attempted improvement on these lines 8. The Germans were patently backward in the field of pulse systems and the majority - if not all - of their navigational aids of this type were copied from Allied methods. 9. The fear of the Allied countermeasures was much to the fore during the last two years and considerable research and efforts was devoted to offsetting such interference and to perfecting systems which would reduce and if possible preclude the danger of jamming. Another factor always present in the minds of those responsible for tactical navigational requirements was that the apparatus must be as light and small as possible because of the limited space available in German aircraft. 10. During the last stages of the war, and as a natural consequence of German air policy, being forced to concentrate on the defensive, thereby involving almost exclusive use of fighter power, a great deal of attention was devoted to the development of simple navigational aids suitable for single-engine aircraft of which Rübezahl was a typical example. D/F LOOP EQUIPMENT. PeGe (Peil Gerät) 6. 11. PeGe 6 was the successor of PeGe 5, the standard loop D/F, set in use at the beginning of the war, and. operated on 150 - 1200 kc/s (2000-250 meters). It provided automatic D/F facilities, the W/T operator merely having to tune to the signal and the "answer" being produced on a course indicator. 12. In the opinion of P/W, who was responsible for operational requirements in the navigational field and who had had fairly extensive navigational experience with K.G.40, PeGe 6 was less reliable than the manually-operated PeGe 5 as the automatic D/F facilities could not distinguish between the true signal and jamming and were apt to record bearing midway between the two if they were near together. The human ear was much more acute and could distinguish the minimum of the real signal from that of the "phoney” one. It had the further disadvantage that it was a heavier piece of equipment than the manually operated set. FuGe 141 13. The FuGe 141 operating on a frequency band of 58.0 - 59.2 mc/s was a receiver with a D/F loop fitted to Air Rescue aircraft used for homing on to the NS 4 emergency radio set carried on the chest by pilots. 14. The NS 4 had a flexible steel tape aerial and batteries which gave it an endurance of 2 to 2,5 hours. FuGe 142. 15. The FuGe 142 using the 2000 - 250 metre band was a small D/F battery set for use in emergency in the event of failure of the aircraft' s electricity supply. 16. The FuGe 142 had a manually-operated loop and its accuracy was only 10° to 15°. 17. When the P/W who, in October 1944, took over the navigational tactical requirements first made its acquaintance, he discovered that the designer of the emergency set, while having the laudable object of assisting a crew in dire emergency when they where probably well and truly lost, had omitted to include any sensing arrangement. The set was, therefore, quickly scrapped as being as much of a danger as an aid. FuGe 145 18. The FuGe 145 was a simple type of D/F set in development for use in single-seater aircraft. It was for use with M/F beacons and was designed for use by coastal reconnaissance aircraft, as for example the Do.335, so that they could obtain a bearing when flying at low level. 19. It was much lighter than the PeGe 6 and had no automatic facilities, but was very easy to operate. P/W had thought that it might ultimately supersede the PeGe 6 for other types of aircraft. Suggested loop for fighter aircraft 20. The research centre at Rechlin had been asked to examine a rough type of loop for singleseater fighter aircraft, which would consist of a loop built into the pilot' s helmet. It was thought that this would enable the pilot to establish the general direction of a beacon by movements of his head and without recourse to the use of a compass. 21. This idea was tried out and seemed promising, but was never fully developed. HOMING BEACONS. Schwanboje. 22. The Schwanboje was a waterborne V.H.F. beacon dropped by parachute and originally used by K.G.40 for marking convoys or submarines. In the autumn of 1944 a 1ine of Schwan buoys was used to aid the He.111's when launching V-1’s from the North Sea against this country. 23. The beacon consisted of a frame aerial and transmitted on a wavelength which could be homed on by the FuGe 17, the standard equipment of K.G.40 in 1942 when the Schwanboje came into use. 24. The set was powered by accumulators and had a live of five hours; by the means of a clockwork device it could be pre-set before release so that it ran for a testing period immediately on release and later started up again after a prescribed interval governed by the expected time of arrival of the homing aircraft. The buoy was fitted with a self-destroying charge operated automatically. 25. A later type of Schwanboje operated on the 38 - 42 mc/s waveband so that aircraft equipped with the FuGe 162 could also use the system. Biene 26. Biene is the code word for a responder beacon. The idea of responder beacons for homing purposes had only been hit on in 1944 and Bienen to respond to the different airborne radar sets were still under development in 1945. The FuGe 243 - Hohentwiel Biene – had been used by coastal units in Norway, in February or March 1945. 27. Responder beacons were also being developed for use in the Baldur method of navigation (see paragraphs 79, 82 of this report). BEAM SYSTEMS. Zyklop. 28. This was the latest form of the well-known Knickebein working on 30 - 33,3 mc/s and received by E.B.L.3 in the aircraft. It was a mobile station which could be fully erected into operation within a week. 29. A still more mobile unit known as the Bock-Zyklop had been introduced. This could be set up in three days and could be adapted for use on the FuGe 16 frequency although as yet, according to documents, no visual indicator for the FuGe 16 had been developed. 30. The 120 W ground transmitter was called the ???? which gave a beam 0.5° wide and a range of 300 km. at a height of 5,000 meters. The Zyklop systems had been made use of on the Russian front up to the end of the hostilities. Sonne. 31. The Sonne beacon system which worked on a frequency of 270 - 480 kc/s was received in the aircraft on the FuGe 10. It was considered an extremely effective daylight system but the range limitation was a disadvantage. Fixes could be obtained from ranges up to 1,000 - 1,200 km. Sonne 6 at Quimper which was the most efficient of the Sonne beacons, had been used on an occasion at a distance of 1,400 km. 32. The sectors served by Sonne covered, an angle of 120 – 150°. The beacon was very reliable over the centre sector of 100°, but the error increased progressively towards the edges of the beam in conformity with the sine law. 33. At night errors up to 4° were liable to occur even in the centre of the sector of the beacon and no real use could be made of it. Mond. 34. To improve the Sonne beacons both in range, and accuracy, an experimental system working on the same principle, but on 3000/6000 kc/s was tried out in 1942. The shorter wave transmission did not prove very reliable and was given up about the end of 1943. Stern. 35. Finally a beacon of the Sonne type under the name "Stern" was designed for use on a V.H. frequency. It, not unnaturally, only gave optical range and was, therefore, of no practical value and was not developed. Dora. 36. One P/W had seen documentary mention of Dora which he believed was a navigational aid system and a precursor of Komet. He did not know whether it worked on the same principle but the Komet experimental site at Kolby was on the former Dora site. Komet. 37. In 1942 the question of navigation over the Atlantic stood in the limelight . As the He 177 was supposed to be coming into service shortly to enable K.G.40 to reach further West, the need for navigational equipment of longer range became acute. 38. A year or so earlier Professor von HANDEL had categorically stated in a lecture that a long-range navigational system based on pulse would inevitably be extremely inaccurate. In view of Professor von HANDEL's views on pulse systems, an improved form of Sonne which would give much greater ranges and be less susceptible to night effect was given high priority. 39. The system evolved was called "Komet" and experimental stations were erected at Bordeaux and Kolby (see A.D.I.(K) 364/1944). The ground station called for an array of no less than 127 masts and 19 control huts in order to cover a 90° sector. It worked admirably provided a 10° sector only was covered, but as soon as the planned 90° sector was put into operation, mutual interference between the masts arose and the various lobes radiated were no longer of symmetrical pattern, with the result that large errors crept in. 40. Research on this delayed the project considerably. After the invasion when long distance reconnaissance in the Atlantic was no longer practical politics, the Komet system was given up without ever having been effectively used. The development people were the more pleased to dispense with it since it left the German radio research and industry free to deal with other more urgent matters. 41. The beacon was to operate on frequencies of 5000, 9000 or 12,000 kc/s received on the FuGe 10K, and it was estimated that ranges up to 3000 km would be obtained. The system employed was to be similar to that used in the Sonne but instead of obtaining one reading per minute, oscillation of the beam was to be speeded up to give 100 readings par minute. 42. The true bearing of the aircraft was automatically recorded by the FuGe 124 which was known as the Kometschreiber. The recording took the form of a series of vertical lines, one for each reading, printed on a strip of paper. At the same time as the lines were printed the Kometschreiber recorded the section of the swept area in which the aircraft was flying, thus giving what amounted to a rough position. 43. The fine reading was obtained from the length of the recorded lines. Any inaccuracies due to night effect could be easily eliminated by averaging the length of the lines, as recorded, on the paper strip, by eye. Erika. 44. Erika was a navigation system (see A.D.I.(K) 364 and 409/1944.) which had already reached the development stage in 1942 but its operational employment was of brief duration and it was soon discarded in favour of Bernhard. 45. Erika was based on the principle of a V.H.F. (30 - 33 mc/s) beam oscillating rapidly over a segment of about 60 – 90°. The beam was phased, a different phase being picked up in different sections of the segment and read off in relation to a standard phase producer in the aircraft. In order to obtain a fix, two such Erika stations had to be received and to receive each station no less than two E.B.L.3's were necessary making a total of four receivers. 46. The range presentation unit in the aircraft, FuGe 121, took the form of a clock-face with a needle indicator and calibrated, P/W thought, from 0 -100. A specially prepared map was required to establish bearing. 47. A disadvantage of Erika was the vulnerability to jamming, interference signals modifying the phase and thereby giving inaccurate readings. The great weight, carried and the bulk of the four receivers, which were particularly cumbersome in the relatively small aircraft in use in the G.A.F. made its widespread use impracticable. Bernhardine. 48. This system was first introduced in 1942 for use by bomber aircraft, but was later dropped in favour of the Benito and Egon control systems. With the increasing British jamming during night raids it was reintroduced for use in night fighter commentary (see A.D.I.(K) 125/1945, paras.5 to 29), which it was thought could only be jammed with great difficulty. 49. The term “Bernhard” was used for the ground stations whilst the airborne recording equipment was called Bernhardine or FuGe 120. The latter made use of the E.B.L.3. receiver as the transmissions lay in the 30-33 mc/s band. 50. At the time of the German capitulation, the following three transmitting stations were in operation, the first two, of which could transmit commentary.- -Thisted, on N.W. coast of Denmark. -Bretstedt, N. of Husum, Germany. -Trebbin, S.E. of Berlin. 51. A further station near Breslau had been almost completed when it had to be dismantled on account of the Russian advance. Additional stations were in the course of construction near Kassel, Munich, Pilsen and Vienna. 52. The Bernhardine system was looked upon as a considerable improvement on Erika. It gave 360° coverage as compared to 60/90° with Erika and, whereas from the jamming aspect stray signals could disturb the phase of Erika causing false indication, in the case of Bernhardine, interference merely resulted in no reading being possible, and furthermore to attain this through 360° a very powerful jamming transmitter flying near the ground station would be needed. 53. The Bernhardine system was not regarded as unjammable but it was thought that use of high power and aerial gain would render jamming by airborne means impracticable. 54. In addition to the E.B.L.3 receiver, the airborne Hellschreiber FuGe 120, also called the Bernhardine, which gave both bearing and commentary was employed. According to P/W the FuGe 120 was large and weighty and the first improvement aimed at was to reduce the weight and provide a set which occupied less space in the aircraft. To this end an attempt was made to eliminate the use of paper strip for the Hellschreiber and a rotating "Folienschreiber" a cellophane paper moving over a sticky carbon surface which constituted a self-eraser - was employed. This projected recording method proved a failure and the use of paper strip had to be reverted to. According to documents the type using paper strip was known as FuGe 120a, and the self-erasing recorder FuGe 120b. 55. A smaller model, the FuGe 120k, to operate on the paper strip principle which constituted the latest improvement, was still in the development stage at the conclusion of hostilities. Previously the ground transmitter broadcast simultaneously from the upper and lower aerial arrays on two frequencies close enough to one another for them both to be received on one channel of the E.B.L.3. One lobe was used for coarse D/F, the other for fine. The two frequencies were then separated by a filter before being fed into the Hellschreiber. The FuGe 120k was designed for use with a ground transmitter operating only on the coarse D/F frequency. The filter could therefore be dispensed with and considerable weight saved in the airborne set at the expense of some accuracy in D/F. 56. With the loss of D/F accuracy the sharp “V” in the vertical printing indicating the reading (see diagram A.D.I.(K) 125/1945 para.18) became a gap about 4° wide. To facilitate the reading of the centre of the gap by eye, and to reduce the size and weight of the apparatus, the vertical lines referred to above were superimposed on the scale which could then only be read in the gap. This allowed the paper strip to be considerably narrower. 57. The FuGe 120k was designed primarily for use in single seat jet aircraft but was also to be embodied in the Ju.88 where space was at a premium, as soon as sufficient numbers of this set were available. Hermine. 58. The Hermine system was originally developed, in response to a tactical requirement formulated during the second part of 1942, as a navigational aid for the purpose of giving an approximate bearing to single-engine night fighters engaged on “Wilde Sau” operations. 59. By the time the initial difficulties in development had been overcome Wilde Sau night fighting had almost ceased; it was found however that Hermine could be used to advantage by day fighters, and it came into operational use. 60. An accuracy of ±5° was assumed, but it was found in practice that this could be improved upon to ±3° by experienced pilots. 61. Thirteen or fourteen ground stations were in operation by Easter 1945 which, P/W claimed, gave complete coverage of the Reich. It was intended to fit two Schlechtwetter (bad weather) Fighter Geschwader with the necessary airborne equipment, and this program had been onethird completed by May 1945. One P/W had heard that ten to fifteen Me.262's of K.G.51 were amongst the aircraft so equipped. 62. The following may be added in modification of the description of the Hermine system given in A.D.I.(K) 125/1945, paras.59 to 62. The Hermine rotating beacon transmits a continuous tone on which is superimposed a speaking clock which counts from 1 to 35, each figure representing tens of degree. Over an angle of about 15° the continuous tone falls to a minimum and rises again. During this period the voice appears to become more audible and the pilot can estimate where the minimum of continuous tone occurs, and so obtain his bearing from the beacon. 63. The beacon recognition is given by means of a self-evident code name for example, "Berolina” for Berlin – which is spoken by the voice in place of 000°. 64. The airborne equipment is the FuGe 125 consisting of the E.B.L.3 with the Tzg (Telephoniezusatzgerät) which enables the 30.0 - 33.3 mc/s transmission picked up on the E.B.L.3 receiver to be heard in the pilot's headphones. Though the Hermine beacons were fully operational there was a scarcity of FuGe 125 sets, as a result of which practical experience of this system was too limited to judge of its efficiency or to lead to further improved tactical requirements been formulated. PULSE SYSTEM. Ingolstadt 65. All the P/W had heard reference to Ingolstadt and agreed that it was a long-range navigational system. 66. One P/W thought that Ingolstadt was the cover name for a pulse navigation system using hyperbolic curves and similar to British Gee; it was originated by Telefunken in 1938 but was then turned down by the R.L.M. In his recollection the original Telefunken idea derived from theoretical discussions at an international conference before the war. 67. As mentioned earlier under the heading of Komet, Professor von HANDEL maintained that owing to the incidence of mutual interference between direct and reflected waves the system was impracticable at long range. In consequence of von HANDEL’s view the system was dropped. 68. Much consternation and annoyance was occasioned in 1944, when it was found that the Allies were successfully operating a similar system. 69. Truhe is the cover name used to describe navigational aid system, using ground stations, similar to those of British Gee. In effect the British Gee stations were also used, the airborne sets being almost identical with the British Gee boxes. Truhe. 70. There is no very distinct difference between "Truhe" and "Hyperbel". The latter term was originally coined to denote our Gee. It was also used when German aircraft equipped with British Gee sets made use of British ground stations. 71. The British Gee chain was used successfully but it was realised that so soon as the Germans lost an aircraft, over England, a change would be made. The German "Y" service monitored the British ground stations to follow any change in Gee phasing and passed advice of such change to their aircraft by W/T. 72. Truhe referred to the German system which was ultimately to cover the 20 to 100 mc/s band and employed various types of ground transmitters including Feuerhilfe, Feuerstein, Feuerzange and Feuerland. All these transmitters could also be used to jam our own Gee, further details of which will appear in a subsequent report on German Radio Countermeasures. The original 46 to 50 mc/s system was known as Truhe I and the new 30 to 60 mc/s system as Truhe II. 73. A chain of Truhe stations was built around Berlin, primarily for training purposes and there were in addition groups of ground stations in the Schwarzwald and in Pomerania. The last named was intended for operations against Russia and it is not known if the stations were destroyed before their capture. 74. The airborne sets which were known as FuGe 122 covering 46-50 mc/s and FuGe 123 covering 25-75 mc/s were replicas of the British Gee boxes and according to P/W were equivalent to British R.1324 and R.1355. These German sets were slightly smaller and more compact than the British sets. 75. Truhe was used by F.A.G.2 and K.G.66, but up to the time of capitulation only a few FuGe 122 and FuGe 123 sets had been produced and only one R.F. box for the latter set. Baldur. 76. The Baldur range-measuring system is comparable to the British G.H. and appears to have been imitated from it. It was referred to by P/W as “Egon in reverse" and was the only navigational system developed by the German by means of which an aircraft could measure distance from a known source as opposed to fixing itself by a position line. As the G.A.F. staff were still thinking in terms of a grandiose bomber policy as late as June 1944, it was intended for use by bomber aircraft for pinpointing targets and for accurate blind bombing. 77. The wavelength employed was in the neighbourhood of 2-4 meters and fell in the SN 2 band. 78. Only two experimental transmitters, both located in Lower Silesia, were erected and one P/W maintained that this system never progressed beyond experimental trials by the manufacturers. It was eventually relegated to low priority owing to the virtual cessation of German bomber operations and the pressure of more urgent demands on radio research and the radio industry. 79. The airborne equipment was known as the FuGe 126 which was made up of a transmitter to interrogate a ground responder beacon, a receiver and a presentation unit. The receiver and transmitter were SN 2 units, though P/W thought they might have been slightly modified for use with Baldur. 80. From documents, the presentation unit appears to have been a modification of the Würzburg range measurement tube, and the accuracy is given as ± 100 meters at all ranges, but this was thought to be purely theoretical and P/W doubted whether it would have been possible to achieve this accuracy in actual practice. 81. A smaller airborne set, the FuGe 126k (k = klein = small) was built for use by single-seat aircraft. In reducing the size and weight of the set, and making it pilot-operated, accuracy had to be sacrificed. P/W, who was responsible for putting up the tactical requirements, considered a clock-face presentation to be the ideal solution. It was expected that the accuracy of the FuGe 126k would then be of the order of 500 meters independent of range. Baldur - Truhe 82. It was planned to experiment on a combination of Baldur and Truhe (Gee) for use by bombers. The intention was to use a hyperbolic grid line of Truhe for the target approach. This could be pre-set, and the pilot could fly along it by keeping the blip centralised, and could ascertain his exact position along the line by measuring his distance from a Baldur beacon. This system was considered simpler particularly for a single-seater aircraft, than the method of using two hyperbolic grid lines or two distances from Baldur beacons. The first experimental sets were to be ready in the autumn of this year. Baldur - Bernhardine 83. A further project was a combination of Baldur and Bernhardine to give simultaneous bearing and range. The range indication was to be obtained by the pilot pressing a knob when the range would appear in kilometres on a dial. This system was suggested for use by both day fighters and bombers. GROUND CONTROL SYSTEMS, Benito. 84. The Benito system of control using FuGe 16, known to the Germans as "Y", is too well known to warrant description. The following paragraphs deal with recent developments. 85. When operating the bomber Benito procedure with the narrow beam. (0.3°) essential for azimuth accuracy, it was easy for the bomber pilot to get on to one of the side lobes in error since these were only about 3° from the main beam. 86. In order to minimise the possibility of mistake and to relieve the pilot of the strain of flying on a beam, an automatic device, the FuGe 28a, was in use which was the improved and final form of the old Y-Gerät of 1941. Documents dated about June 1944 show that it was used in conjunction with FuGe 17, but P/W thought that it had been modified for use with FuGe 16ZY as well. 87. The procedure was that the bomber pilot flew on instructions conveyed over the FuGe 17 until it had been established by ground D/F stations that he was on the true beam, when the code word "Bako" would be given whereupon the pilot would switch on the FuGe 28a which took over control of the automatic pilot and kept him on the beam. 88. P/W gave the accuracy of range measurement with the Bomber Benito procedure as only ± 1 km. at maximum range. Egon. 89. The original Egon procedure which involved the use of two Freyas, the one for rough positioning and the other for fine positioning - later became known as "Egon Einstand" (One location) to differentiate from an improved system termed “Egon Zweistand” 90. Egon Zweistand was evolved to offset the inaccuracies in azimuth D/F, and cash in on the range accuracy of radar. With Zweistand a third Freya was introduced, placed some considerable distance from the other two Freyas in order to give a distance cut. It was intended for use by bomber aircraft operating over England or on long range sea missions. 91. The original Zweistand system, which was first tried out in Italy by a Schlacht unit, was somewhat primitive in that the readings from the extra Freya were telephoned through to the plotting centre and worked out before being plotted on the Seeburg table. 92. To eliminate the delay thereby involved a landline connection was introduced to feed the Freya pulse to the C.R.T., which then had two blips showing ranges from the two Freya sites. The vulnerability of landline to disturbance and destruction later led to the development of a W/T transmitter and this method was employed successfully in operations. 93. Since the Freya pulse was not strong enough to trigger off the FuGe 25A at ranges exceeding 250 kilometres, it was planned to supplant the Freya by extra powerful Wassermanns, and thereby increase the effective range of Egon Zweistand to 350 kilometres. 94. A further line of development was the provision of a new type of control table giving the exactitude of plotting necessary for pinpoint bombing. This control table, which was under development at Rechlin, made use of complicated mechanical apparatus for accurate projection of the position of the bomber. One of these tables was destroyed in the course of a daylight air attack on Rechlin in February 1945; two other tables were in existence at the time of the capitulation, and were located somewhere in Western Germany. 95. Egon when first introduced was received with some scepticism by the crews, as it was felt that it was too vulnerable to jamming. After it had been used operationally without being jammed in the attacks on London in March 1944, the procedure was adopted with greater confidence, and it gained a good reputation. As recounted in A.D.I.(K) 343/1945, Egon was always favoured by the R.L.M. technical development section in preference to Benito control. 96. A drawback of the system was its restricted range at low altitude, which according to P/W was the reason why it was not used in conjunction with V.1 operations. Nachtlicht 97. The Nachtlicht system was the first method of control not using R/T speech to be improvised by the Germans, and had been tried out during the raids on London in the spring of 1944. 98. It had been observed that the red signal lamp of the FuGe 25A was illuminated when the aircraft was being swept by a Freya, and it was suggested that use could be made of this as a means of transmitting morse signals from the ground. A Freya operating on a special wavelength, which P/W thought was 2.55 meters, was set up on the Channel coast and was used to send simple instructions to the aircraft attacking London by means of visual morse indications on the lamp of the FuGe 25A. 99. The primitive method of giving distant control indications was the forerunner of "Nachtfee", "Barbara" and "Barbarossa". 100. Luftkurier was the first development of the Nachtlicht idea. It was primitive device intended to give visual indication to the pilot by means of a pointer which was started and stopped by the reception of pulses. 101. P/W thought that Luftkurier was first tried out by K.G.66 on the Freya band, but it was so easy to jam by the addition of extra pulses that it was never developed. Nachtfee 102. Nachtfee was the term used to describe a system for the transmission of control instructions to a pilot in the beam of the controlling Freya through the medium of a C.R.T. indicator similar to the Lichtenstein range tube. The airborne equipment used was known as FuGe 136 and weighed 12 kg. 103. The original purpose of Nachtfee was, to provide a solution to the jamming of R/T control systems, and it had been used operationally by the Pathfinders of K.G.66 for mines in the Scheldt estuary. It was to be adapted for use by night fighters to overcome our jamming of the night fighter commentary. 104. Nachtfee was a system using the FuGe 25A as receiver. 105. The presentation screen in the aircraft was inscribed with various commands both on the inside and outside of a circular time trace. There was a stationary zero blip in the 12 o'clock position, and when an instruction was radiated the pulses received caused a second blip to emerge from the first and travel round the C.R. tube in a clock-wise direction, presumably by a slight change in p.r.f. This blip came to a stop and the command corresponding to its position could be read off on the inside of the time trace where a total of about eight different instructions were inscribed. It took from one to two second, for the blip to travel round the tube. 106. It was thought that the further eight commands inscribed on the outside of the time trace were denoted by the blip making a complete circle starting round a second time before coming to rest at any one of the eight sectors. In this way a total of sixteen different orders could be given. For night fighters such instructions as "turn left/right", "climb", "dive”, etc. appeared on the inner side and figures for transmitting bearing on the outer side of the trace. 107. This system was used operationally, but it was found that, apart from the susceptibility to jamming, other pulse transmissions could interfere by unlocking the system and thereby cause wrong positioning of the indicator blip. 108. Another pronounced objection to the Nachtfee lay in the fact that it was necessary for a member of the crew to watch the C.R.T. indicator uninterruptedly for missing one blip indication might give the message a false value. It was not therefore possible to use it in singleseater aircraft. Barbara 109. This apparatus, also called FuGe 138, consisted of an attachment to the FuGe 25A receiver and only weighed 2 kg. This unit contained an audio filter which allowed the pilot to hear morse signals superimposed on the Freya interrogator transmission if they were emitted on a suitable audio frequency usually about 800 cycles. By keying other morse signals on different audio frequencies and equipping aircraft with suitable filters, more than one aircraft could be controlled by a single Freya. 110. Barbara was to be used for Egon control of ground-strafing aircraft and bombers but not for night fighters. 111. In the Germans' opinion there were three disadvantages, namely that the Allies could intercept and make use of signals so transmitted, that the aircraft had to be in the beam of the Freya if it were to receive, and so an aircraft "lost" by the Freya owing to jamming could not be communicated with and finally that, though intended for single-engined aircraft, fighter pilots rarely had sufficient command of morse to be able to use this type of control. Barbarossa 112. Barbarossa was a set designed to meet the same requirements as Barbara but to remedy two of the drawback mentioned in the last paragraph. 113. The instructions to the aircraft were to be transmitted by code pulse modulations which were passed through a "pulse filter" in the airborne set and a written indication obtained on a Hellschreiber. The pulse filter and Hellschreiber unit were attachments to the FuGe 25A and were known as the FuGe 139. This apparatus was in development at Rechlin under the supervision of Stabs.Ing. von HAUTEVILLE. 114. With this arrangement pulse modulations could not be read by the Allies, and for spoof purposes in order to produce a wrong indication we would have had to know the exact type of modulation accepted by it. Visual indication was also quicker and did not depend on knowledge of morse. 115. This scheme was only in a very early stage of development and P/W were unable to give details. It was hoped that in due course it would be possible to develop matters a stage further and find a means of transmitting scrambled speech instead of morse, but P/W understood that the question of pulse modulation for speech transmission had not been solved. Rübezahl 116. Consideration had been given in 1945 to the introduction of a crude system of navigation which could be only used within the boundaries of the Reich. This was to go under the code name of Rübezahl, and the fact that it was seriously considered and actively supported by the P/W responsible for Navigational Aids on the G.A.F. signals staff is an interesting reflection of the depths to which a combination of Allied jamming under-trained fighter had forced German technique. 117. It was expected that in the course of the summer of 1945 thousands of 162 Volksjäger would be available for the protection of the Fatherland. They were to be equipped with FuGe 24, which was to become the standard G.A.F. R/T set as described in A.D.I.(K) 343/1945. This set did not for the present give Benito control facilities and indeed as they were short-range, high speed, fair-weather aircraft it was not certain that Benito control would be essentially needed. 118. It was essential that their relatively inexperienced pilots should have a simple means by which they could locate their approximate position without any additional navigation equipment having either to be manufactured or carried in the aircraft. It was therefore decided to develop a system which could be used with FuGe 24. 119. In order to direct the Volksjäger pilots to their target, recourse was to be had to the night fighter system of broadcasting a commentary, and this commentary was to be combined with the primitive navigation system Rübezahl. 120. It was therefore planned to set up ground transmitters over Germany at 30 km intervals. The transmitters were to be beamed upwards, so that at 6,000 meters the polar diagram was about 40 km in diameter and lobes from neighbouring transmitters just overlapped, thus covering the whole area. Each transmitter emitted a plain language recognition signal in the form of the name of its district, e.g. Halle, Magdeburg, etc. 121. All transmitters were to be operated on the same frequency so that to locate himself the pilot merely tuned his FuGe 24 to the frequency for the day. The ground transmitters were to be adapted from the FuGe 15 transmitters which had been manufactured in quantity as described in paras. 23-39 of A.D.I.(K) 343/1945 before it was found that the FuGe 15 was unsuitable as an airborne R/T set. They were renamed Bs.15 (Bodensender). 122. Later it was believed that the night fighters which were also to carry FuGe 24 (see appendix 1) would also use the Rübezahl commentary as yet another alternative source for vectoring themselves to the bomber stream. |
German traffic analysis of russian communications
EXTRACTS FROM TICOM REPORT I-112 : VOLUME 9--GERMAN TRAFFIC ANALYSIS OF RUSSIAN COMMUNICATIONS Lt. Werner RASCH, of the 353rd German Air Force Signal Intelligence Regiment in the East, gives the folloving account ot the development and achievements of the Russian Long Range Bomber Forces (ADD--Avitsiya Dalneye Dyestviya). "Soon after the outbreak of the Russian-German . war, practically allot the Russian Long Range Bomber Porce was destroyed, either by German attacks on Russian airfields, or in combat with Geman fighters. What was lett of it was withdrawn from action. Marshall GOLOVANOV, chief of ADD, reorganized his forces with the intention of using them in night opera~ions only, owing to the threat presented by the strong German flak defense. The first successful operations following the reorganization took place in the battle of Stalingrad (September 1942 - February 1943). From then on, ADD operations played an important part in all Russian ottens1ves. The training for night operations was of long duration; at the end of'the war each bomber reg1ment had crews which were still in a training status. . "The achievements of' the ADD units were not - very impressive. Crews were not trained tor carrying out night attacks in close formation. In the latter days of the war 60 aircraft of a division need approximately one hour to assemble and take off, and even this was accomplished only- under the most favourable navigational and meteorological conditions. In planning an attack, each division was allotted 20 minutes over the target; in that time it was intended that all aircraft or one division should have completed their mission and moved out to make room for the next division. Unless targets on the front itself were being raided, the front line was usually crossed before dark. This permitted the take-off to be made during daylight, and the first aircraft to take of were held in an assembly area in order that a close-flying formation be formed. Formations equipped with radio-telephone communications were again brought into close order by the leading aircraft of the regiments before going into the bomb run. Each regiment had several Pathfinder aircraft, which were flown by the most experienced crews. Since the success of the mission depended upon the1r efforts. In addition to theflares, they usually carried a 1,,000 pound bomb.Point-to-Point Nets. --These po1nt-to-point nets of the Long Range Bomber Forces (ADD) alone were a sufficient basis on Which the Germans could build up an accurate picture ot the ADD organization. When the 18th Russian Air Army was reorganized the Germans immediately recognized such steps from traffic on these nets. The most profitable traffic in these nets from an intelligence standpoint, came from units which were widely separated in the field as this necessitated the use of radio facilities for communication. In instances where the units were close together very little s1gnal intelligence could be gained since there was slight need tor radio transmissions. From the intercept and analysis of traffic on these point-to-point nets movements ot the Russian Air Army units, locations and occupations of airfields numbers of operational and unoperational aircraft and locations of supply dumps could be determined. Traffic intercepted-on these nets also gave the Germans considerable information regarding intended operations and offensives. One outstanding success along this line occurred when a Russian order to bomber units was intercepted by the Germans. The message ordered an attack on Shavli, Lithuania, where an entire German Panzer Army was immobilized due to a lack of sufficient fuel. The German Signal Intelligence Service reported the information to the Lufttlotte which provided fighters to meet the Russian Long Range Bombers while German JU 52' s dropped gasoline supplies to the encircled Panzer Army and enabled it to escape. Call Signs and Frequencies. --Three-character call signs were used in the radio nets between the Air Army and Air Corps. They were changed once during the day and once at night, at which time the frequencies also were changed. I. Call signs were based on an arbitrary combination of letters and digits and were selected from a call sign list that changed monthly. The Germans were unable to determine whether any definite system was employed for the choosing of the call signs. They did notice however that during the course of a month a call sign used by a given radio station might be repeated without the succession of call signs which had followed at the time of the previous occurrence. Traffic between corps and divisions took place with a periodic change of call signs, but on fixed trequenc1es. This fact aided the intercept tasks of the German Signal Intelligence." … "a. Supply Traffic. --Valuable intelligence was obtained by the German Signal Intelligence from the interception of [RUSSIAN] radlo traffic which gave details on supplies of fuel, ammunition and other materials. Details of railway movements of supplies were transmitted by the District Air Base Depots to thier subordinate airfield battalions. These messages contained information on the destination, number or railway cars being used, amount and type of supplies, and the scheduled time of arrival. When the trains arrived at their destination a message announcing their arrival was sent to the airfield battalions. As a result ot the exploitation of this type of traffic the Germans were able to bomb successfully the stations soon after trainloads or fuel and ammunition had arrived. In the Southern sector a service Command point-to-point radio net reported arrivals of replacement aircraft tor the 17th, 5th, and 8th Air Armies. These replacement planes were ferried from the factories to the airfields. Tactical'. units down to regimental level receipted for these planes and supplies, and from interception of these strength reports the Germans were able to estimate the production and distribution rate of Russian planes. Current fuel and ammunition supplies at airfields were reported on pre-arranged message forms transmitted by the air-field battalions. These messages, since fuel and ammunition supplies were always increased prior to an offensive, afforded the Germans a sund basis for predicting impending Russian offensives. b. Miscellaneous Air Service Command Traffic. --The Russian Air Service Command reported by radio on the achievements in salvaging German aircraft which had been shot down or which had been forced to land. These reports afforded the Germans with a source of informat1on concerning their missing crews, and in many, cases it was possible for the Germans to inform families that the crew members were alive and were Russian prisoners of war. Reports of interrogation of captured German military personnel were also often transmitted and intercepted by the Germans. In some cases as a result of the information contained in these reports, the German Command carried out court martial proceedings in absentia where the intercepted information carried sufficient proof that the German prisoners of war had revealed information of a secret nature. An Air service Command of the 8th Russian Air Army on the southern front reported routes to be flown by aircraft in large-scale ground attacks, giving the time at which the attack would take place. For such attacks the Russian Air Army usually ordered the placing of smoke markers in the frontal area on the day before the attack would take place. These smokemarkers were used by the Russian planes as an orientation point, and not only indicated the proposed direction to be flown, but also corresponded to the direction the ground force would advance. After a study of these smoke signals the German Air Force Slgnial Intelligence learned that the signals were lit thirty minutes to an hour before the actual time of attack. Thus, when it was learned that smoke signals had been set out the German Signal Intelligence could usually inform the Air and Ground forces some twenty-four hours in advance of plans tor a Russian offensive." |
Re: Researching the Luftwaffe through Prisoner Interrogations
Thanks Bruce, these continue to be fascinating reading, nice to see the other side of the hill, so to speak. Getting Court Martial proceedings against you in absentia, not good, hope nothing happened to the relevant families.
cheers Allan |
PREDICTING ALLIED BOMBING ATTACKS
4 Attachment(s)
TICOM I-109
Extracts of translation from report of Lt. LUDWIG of Chi. Stelle O.B.d.L (note: TICOM report is dated post-war but no date is given for original report from LUDWIG.) |
All times are GMT +2. The time now is 03:57. |
Powered by vBulletin® Version 3.7.2
Copyright ©2000 - 2024, Jelsoft Enterprises Ltd.
Copyright ©2004 - 2018, 12oclockhigh.net