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Luftwaffe and Axis Air Forces Please use this forum to discuss the German Luftwaffe and the Air Forces of its Allies. |
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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"
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#12
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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."
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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"
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http://www.filephotoservice.co.uk/ RESEARCH AT THE NATIONAL ARCHIVES & OTHER UK INSTITUTIONS |
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Re: Using Ultra to research the Luftwaffe
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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. |
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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"
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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."
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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"
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Re: Researching the Luftwaffe through Prisoner Interrogations
Fascinating, especially by U.S. Air Interrogation.
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Re: Researching the Luftwaffe through Prisoner Interrogations
ADI K 065 5/NJG 101 Ju 88.
Junker Last edited by ju55dk; 6th June 2020 at 21:17. |
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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.)"
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