Luftwaffe and Allied Air Forces Discussion Forum - Researching the Luftwaffe through Prisoner Interrogations

"SECRET A.D.I.(K) Report No.160/1944
THE FOLLOWING INFORMATION HAS BEEN OBTAINED FROM P/W
AS THE STATEMENTS HAVE NOT AS YET BEEN VERIFIED, NO
MENTION OF THEM SHOULD BE MADE IN INTELLIGENCE
SUMMARIES OF COMMANDS OR LOWER FORMATIONS, NOR SHOULD
THEY BE ACCEPTED UNTIL COMMENTED ON AIR MINISTRY
INTELLIGENCE SUMMARIES OR SPECIAL COMMUNICATIONS.
A G.A.F. PATHFINDER UNIT.
Further Report on Ju.88 S-1, Z6+IN, of 5/K.G.66, brought
down in the sea off Brighton on 25th March 1944.
(Previous A.D.I.(K) Report No.141/1944).
1. The present report may be taken as the third of a series -
the first two in which were A.D.I.(K) Reports Nos. 64 and
108/1944 - dealing with the most recent G.A.F. pathfinder
practice.
2. The principal subject of interest which has emerged from
the interrogation of the one survivor of the Z6+IN is the
employment by his Staffel of a method of target pinpointing
known as the Egon procedure.
3. Since the issue of the last pathfinder report, the pilot
of the Z6+HK, who was wounded when shot down on February 24th,
has become available for interrogation and he has also
contributed to the information which this report contains on
the activities of I/K.G.66.
EGON PROCEDURE
4. On the night of 24th/25th March, the Z6+IN of 5/K.G. 66
was engaged in pathfinding for the attack on London; the
petrol tanks were holed by A.A. fire and on the way home the
aircraft came down in the sea through lack of fuel after the
crew had baled out.
5. The Z6+IN, which was equipped with the FUG.25a, FUGe.10,
FUGe.16, PeilGe.6 and the FUGe.216 ("Neptun") tail warning
device - the latter out of order - had laid its flares by
means of course and pinpointing data supplied by its own
ground control.
6. This system of controlling aircraft from the ground is
known as the "Egon Verfahren" (Egon Procedure) and in
operation depends upon response radiated by the FUGe.25a in
the aircraft being picked up and D/F'd by two Freyas.
7. During flight, the position of the aircraft is
continuously plotted by means of data supplied by the Freya
and necessary course corrections are passed to the aircraft by
ground control in the form of coded W/T and R/T signals.
8. Orders for flare or bomb release are similarly
transmitted, allowances for drift being taking into account by
the plotting centre; an accuracy to within 0.3° - or according
to P/W about 200 metres - is claimed for the placing of the
flares. (It should be noted that 0.3° at a distance of as
little as 150 km. is nearer 900 m.)
9. The Egon Procedure at present being used, relying as it
does on course and bomb-release signals passed by W/T and
R/T, is as yet only in an extemporised form. A new attachment
to the FUGe.25a in the aircraft will shortly provide for
visual signals appearing on a Cathode Ray Tube and will
eliminate all W/T and R/T course and bombing signals without
basically altering the present procedure.
10. This attachment is now being tried out by 4/K.G.66 at
Strausberg and according to P/W it is about to be introduced
into operational use; the apparatus and its method of
operation are described in a later section of this report.
Operation of Egon Procedure.
11. At the briefing for a pathfinder operation, crews are
given a course to the target and a height at which the flares
or bombs are to be released.
12. After take-off, the FuGe.25a in the aircraft is switched
on and Freya No. 1 plots the aircraft; the FuGe.25a radiations
giving the single-letter recognition characteristic of the
aircraft are received by the Freya and range and bearing data
are passed from the Freya to the plotting room.
13. The Egon plotting table is similar to the night-fighter
Seeburg Tisch; a transparent map of the area of operations is
laid on a glass table and the aircraft is represented by a red
spot of light which is thrown on the underside of the glass by
an automatic projector connected directly to the Freyas. The
course of the pathfinder aircraft can thus be followed
visually and any corrections necessary are given by Control.
14. In the vicinity of the target Freya No.2 takes the
aircraft over from Freya No.1 and thereafter no further course
corrections, but only the flare or bomb release instructions,
are given.
15. The height of the aircraft cannot be checked by the ground
Control and it remains with the pilot to see that his height
at the time of release conforms with the instruction given at
the briefing.
16. When marking targets over London the aircraft were usually
briefed to fly over southern England at 9,500 metres, reducing
height to 8,500 metres to release the flares. The height of
flight given at the briefing for Egon-controlled aircraft was
never less than 6,000 meters over London.
Communication with Aircraft.
17. The whole of the Egon procedure depends in its operation
on a short series of code-words used in communication between
Control and aircraft; these code-words are already familiar,
having been borrowed from the G.A.F. controlled nightfighters.
18. It, was stated by P/W that recently the R/T channels of
communication had been seriously disturbed by British
countermeasures and to combat such interference it has
recently been the practice to transmit all traffic passing
from Control to the aircraft in R/T and W/T simultaneously,
the latter in two different channels.
19. The R/T traffic passes on the frequency band of the
FuGe.16 whilst both the W/T channels are within that of the
FuGe.10 and PeilGe.6. One of these two W/T channels is
received by the aircraft on the PeilGe.6; this is on a
frequency of 563 kc/s., the signals being superimposed on the
broadcasting programme of Calais I - the familiar vehicle for
the outpourings of one William Joyce. The other is received on
another frequency on the FuGe.10,
20. The series of signal code-words, their equivalents in the
morse channels and their significant in the procedure are as
follows:-
W/T R/T Meaning
(Preceded by a/c call-sign)
KKK Kommen You are being plotted.
AAA Autobahn Change bearing to.....
RRR Rolf Bearing 5° right.
2 RRR Zweimal Rolf Bearing 10°right.
LLL Lisa Bearing 5° left.
UUU Kirchturm Height
CCC Caruso Fly straight and level cours.
ZZZ Pauke Pauke Open bomb doors.
-(dash) -(W/T dash) Pre-release signal of 3-4 secs.
.(dot) .(W/T dot) Bomb or flare release signal.
? Kurfürst Acknowledge that signal is
understood,(reply on FuGe.25a)
AAA HHH Autobahn Mat Set course for base.
(Heimat).
21. In operations the first signal which passes from Control
to the aircraft is the information that Freya No.1 has engaged
the aircraft and plotting has commenced. This signal opens
with the aircraft call-sign, e.g. CA1, followed by KKK or
Kommen; in subsequent signals the two letters of the aircraft
call-sign are omitted and the number only given.
22. The aircraft has no communication with its control but
replies to this and other signal, by manipulation of the
FUGe.25a - switching off for 3-4 seconds signifying that the
signal has been received and understood and repeated switching
off and on signifying the contrary.
23. Course corrections are passed to the aircraft in units of
5°, represented by the code-words Rolf or Lisa or their morse
equivalents; thus Rolf or Lisa = 5° and three times Rolf or
Lisa = 15°, In passing such instructions, Control signals the
aircraft's call-sign followed by the following type of
message:-
R/T: Autobahn dreimal Rolf.
W/T: AAA - 3 - RRR.
24. Whilst the aircraft is being followed by Freya No.1, any
necessary corrections in course continue up to the point where
the order is given to fly on a straight and level course after
which no further course corrections are made and orders for
release of flares follow.
25. When the aircraft is in a position to commence the bombing
run the order "Pauke Pauke" (open bomb doors) is given, at
which point Freya No.2 takes over and a pre-release signal of
a single dash is given, followed by a release sign of a single
dot.
26. The aircraft then signals "Quitting" (operation completed)
by manipulation of the FUGe.25a switch, Control gives the
order to return, and the aircraft is vectored back to base.
27. It is noteworthy that for this purpose again the
subterfuge of Calais I has been resorted to; on the last
flight of the Z6+IN the crew was briefed to return to
Montdidier unless the march "Kommt zurück" ("come back") was
played by Calais; on hearing this tune a landing was to be
made at Soesterberg. "Kommt zurück" was duly played and the
Z6+IN was on its way to Soesterberg when it came to grief off
Brighton.
28. It was stated that with the Egon procedure it was possible
for the ground control to direct one aircraft every ten
minutes; it is the practice, however for the flare dropping
aircraft to orbit the target after release of one cluster of
flares and to be controlled in a second run over the target
after an interval of six minutes to renew the concentration
before the first flares have burned out.
EGON GERAT - FUG.25a ATTACHMENT.
29. The introduction of the attachment to the PuGe.25a,
consisting of a Cathode Ray Tube presentation unit, will
dispense with all W/T and R/T signals as navigational aids in
the Egon Procedure.
30. The attachment, which was invented and tried out at
Rechlin by one Stabsingenieur BENES, consists of a unit placed
in the fuselage of the aircraft and a presentation unit,
placed between the pilot and observer, embodying a Cathode Rey
Tube of about the same diameter as that of the Lichtenstein.
31. The attachment was thought by P/W to have a common aerial
array with the FUGe.25a, the latter aerial being a rod about
35 om. in length.
32. The scale of the Cathode Ray Tube consists of a circle
divided into equal segments, each of which represents, and is
marked with, one of the code-words used in the Egon Procedure.
The circle is surrounded by an outer circle which is marked
clockwise from 0 to 9, the 0 being at 12 o'clock in the
circle, so that the whole scale has much the appearance of a
dartboard.
33. In operation, the Egon Procedure will be followed in the
manner already described, but the visual signal on the tube
will replace the aural signals at present in use.
34. A short blip, radiating from the centre of the tube, first
appears in the segment representing the appropriate signal,
such as "Autobahn". Bearings are than given in the same way by
a long blip, also from the centre, appearing opposite a
succession of figures in the outer circle, for instance 3
followed by 5 and 5 repeated represents 355°.
35. Course corrections can similarly be given by a short blip
appearing for example, in the "Rolf" segment followed by a
long blip opposite 3 in the outer circle, which would mean '3
times Rolf' or a correction of 15° right.
36. Height can similarly be given by indicating "Kirchturm",
followed by the necessary figures.
TARGET MARKING PROCEDURE.
37. According to the pilot of the Z6 + HK, which was shot down
on 24th February 1944, the Verbandsführer - Master of
Ceremonies - is being employed in target marking procedure;
this was denied by the P/W from the Z6+ IN, who was in another
Staffel, but the pilot of the Z6 + HK claims to have acted as
Verbandsführer on his last operation.
38. It was stated that the first pathfinder aircraft and the
Verbandsführer arrive simultaneously over the target and when
the pathfinder aircraft lays the first flares their position
is checked by the Verbandsführer from a higher altitude.
39. If the flares have not been correctly laid, the
Verbandsführer drops a single red flare, which he places above
the false cluster as a sighn to the attacking force; by then
himself proceeds to place flare in what he considered to be
the correct position. If by now the attacking force to nearing
the target, he is said to inform the formation leaders by R/T
in clear of the change in marking and that the false cluster
is to be ignored.
40. It is noteworthy that both of the present P/W were
convinced that decoy flares have been dropped on several
occasions during attacks; P/W stated that this would be
countered by the Verbandsführer announcing this by R/T and/or
dropping a flare of a different colour.
41. The burning time of the normally used single candle flare,
the Mark.C.50, is given as seven minutes and these are renewed
by the pathfinder aircraft, with the help of navigational
aids, in their sixth minute of burning.
42. The normal load of flares carried by the pathfinder
aircraft is eighteen Mark.C.50's; these are dropped in three
runs with six on each run, or alternatively in two runs of
nine.
I/K.G.66.
Order of Battle.
43. According to the most recently captured P/W, I/K.G.66,
although it has for some time had a strength of five Staffeln,
is still nominally one Gruppe. Up to 25th March 1944 the
disposition and equipment of these Staffeln were as follows:-
Staffel Equipment Base
1&2/K.G.66 Ju.88 S-1 Avord, forward base
Ju.188 Montdidier.
3/K.G.66 Ju.88 S-1 Cormeille-en-Vexin.
Ju.188.
4/K.G.66 Ju.88. Strausberg
Ju.188.
5/K.G.66 JU.88 S-1 Avord and Montdidier.
44. Up to about the first week in March the 1st, 2nd and 5th
Staffeln were based at Montdidier but continued attention from
Allied aircraft, including a fighter-bomber attack in which
three aircraft were destroyed, forced a move further back to
Avord, K.G.40 being ousted from that airfield in the process.
45. Aircraft of all three Staffeln still used Montdidier
operationally, however, and fuelling facilities were available
there; it was usual to fly from Avord to this airfield
immediately before starting off on operations.
46. Major SCHMIDT is still Kommandeur of I/K.G.66, he just
escaped being written off recently, however, when his aircraft
was shot down by Mosquitoes between Avord and Montdidier. His
crew was killed.
47. Hauptmann SCHMIDT, the Staffelkapitän of the 2nd Staffel,
was lost in the attack on Hull on 19th March; his successor is
not known.
48. Oberleutnant de MILDE, a signal officer formally at Halle
is Staffelkapitän of the 3rd Staffel and Oberleutnant BÖHMANN
now commands the 5th Staffel.
49. The 5th Staffel has sixteen officers on its strength, most
of whom are signal officers. Two of these are Leutnant
SCHUBERT and Leutnant MEUHAUSER.
ACTIVITIES OF I/K.G.66
50. It must be emphasised that recent P/W of K.G.66 have had
small knowledge of the activities of other Staffeln of the
Gruppe beyond their own; the W/T operator of the Z6+IN,
although he claimed a knowledge above the average, must be
classed with the other P/W since his information was mainly
from hearsay. He, like the others, can only be relied upon
where his own Staffel is concerned.
51. The 5th Staffel was formed in about May 1943 from
personnel of the 3rd Staffel, with the addition of some crews
from K.G.6. Losses, which have been heavy, have since been
replaced with crews from the other Staffeln of K.G.66 as well
as from K.G.54 and K.G.2.
52. This Staffel commenced operations with target marking by
D/R but in about December 1943.
December 1943 the Egon Procedure was practised at Rechlin and
later on from Montdidier.
53. According to this P/W the activities of the Staffeln of
I/K.G.66 are at present divided as follows:-
1st Staffel....
thought to be engaged as backers-up.
Navigational aid used uncertain.
2nd Staffel.... Pathfinding, using "Gee" (see A.D.I.(K)
108/1944).
3rd Staffel....
Known as the Störstaffel (jamming Staffel).
Radar investigation and jamming flights.
4th Staffel.... Non-operational: perfecting new Egon
apparatus as well as trying out a "Queen
Bee" aircraft.
5th Staffel....
Known as the "E" Staffel: pathfinding using
the Egon Procedure.
INVESTIGATION AND JAMMING.
54. The Störstaffel - the 3rd - is said to have commenced
operating in August 1943 in the fields of the anticipation and
attempted diversion of Bomber Command night attacks.
55. A few Ju.88 S-1's of this Staffel are variously equipped
with the Hyperbel Gerät, the "Naxos" search receiver such as
is used in U-boots for the detection of Radar transmission,
and a set known as the "Viktor 1" for jamming R/T.
56. In operations, an extra member of the crew is carried - an
English speaking signals officer - sometimes the aircraft may
be fitted with drop tanks.
57. When making investigation flights with the object of
anticipating Bomber Command's targets, the aircraft are
allotted specific areas of operation - the area off the North
Sea coast between Boulogne and Denmark has the code-word
"Rodelbahn" - and the first duty of the special W/T operator
is to discover any British navigational aids which may be in
operation.
58. The frequencies and bearings of such transmissions are
passed to a plotting centre which, using data from several
investigating aircraft, instigates counter-measures to the
navigational aids and the laying of decoy flares short of the
conjectured target.
59. Should the British navigational aids in use be discovered
in the earlier stages of an attack, the practice is said to be
to withhold any countermeasures until the later stages, to
ensure that no intermediate evasion of these countermeasures
can take place.
60. It was stated that the Staffel was at present only making
these investigational flights as far as Western Germany but
that they had already claimed some successes in their efforts
to divert attacks.
FW.190's ON NIGHT OPERATIONS.
61. It was stated that the, F.W.190's of S.K.G. 10 which use
Rosières and an airfield in Holland as their bases are now
equipped with FuGe.25a and controlled by the Egon Procedure.
62. Several pilots of the F.W.190's are said to have reported
wonderful bombing results before the installation of the
FuGe.25a took place, whereas they in reality merely made a
pleasant flight over some innocuous area and jettisoned their
bomb. With the introduction of the FuGe.25a many of the pilots
who did not understand its functions are said to have found
themselves facing a court martial.
63. The signal to the F.W.190’s to remain over the target was
stated to be "Walzer" and the homing signals the words
"Radetzkymarsch".
A.D.I.(K) S.D.Felkin
5th Apl.44. Wing Commander
AMENDMENT TO A.D.I.(K) REPORT NO. 160/1944.
Paragraph 27: Delete and substitute:-
"27. It is noteworthy that for this purpose again the
subterfuge of Calais I has been resorted to. In the last
flight of the Z6 + IN the signal for the crew to return to
Montdidier was to be the tune "Komm' zurück, ich warte auf
dich" (well known in this country under the title of
"J'attendrai") played every three minutes by Calais; if this
tune was not played, the crew was to land at Soesterberg.
"Komm' zurück" was duly played and the Z6 + IN was on its way
to Montdidier when it came to grief off Brighton. The pilot of
the Z6+HK also referred to a procedure of this nature. He
stated that the playing of a waltz was the signal to remain
over the target and the Radetzky March the signal to return to
base. No doubt the tunes played and their significance would
be varied from sortie to sortie."
Paragraph 63: Delete."

then in a second file this ...

"Further Report on the Crew of the Ju.88 8-3 Z6 + FH of
1/K.G.66) shot down by A.A. 5 miles N.W. of Alost, on 23rd
January 1945.
(Previous A.D.I.(K) Report No.142/1945)
LAST FLIGHT.
1. It will be remembered that this aircraft was brought down
while acting as pathfinder to a minelaying operation in the
Scheldt Estuary. The flight was described in detail in the
previous report and there is only one point of interest to
add; that after marking the minelaying point at the mouth of
the Scheldt, the Z6 + FH was to go on to attack the night
fighter airfield at Knocke/Le Zoute, for which purpose 18 x 50
kg. S.D. bombs were carried. If the lighting at Knocke
airfield was not on when the crew reached it they were to use
their bombs on A.A. batteries as targets of opportunity.
I/K.G.66.
2. It is confirmed that 1/K.G.66 based at Dedolstorf has
reverted to its old duties as a specialised pathfinder unit.
It is organised in the same way as when it operated against
England in the spring of 1944, that is to say with the 1st
Staffel using the "Y" procedure, the 2nd the "Truhe". (the
German equivalent of Gee), and the 3rd the EGON procedure.
There is, however, one important innovation; the lst Staffel
has been receiving instruction in a new navigational method, a
combination of the "Y" and Egon procedures, which will be
described in a later section of the present report.
3. P/Ws' knowledge of the Gruppe's activities was confined to
their own Staffel; they knew that the 2nd Staffel used "Truhe"
and that there were a number of German Gee stations, but they
did not know the locations of the latter and could give no
further details.
4. Shortly before the crew of the Z6 + FH was shot down, the
1st Staffel had received three new crews, bringing their
strength up to 12. Aircraft for these new crews, however, had
not yet arrived.
ACTIVITIES.
5. The present crew had joined 1/K.G.66 at Dedolstorf in May
1944, having previously been with 4/K.G.54, with which unit
they had flown 7 operations in Italy and 10 against this
country.
6. At Dedolstorf they did little or nothing during the summer
of 1944 beyond some very scanty training and they did not make
their first operational sortie until December 4th; this was a
weather reconnaissance over an area of the North See East of
the Thames estuary in preparation for a mining sortie in the
Scheldt that same night.
7. In about October or November it had been known in K.G.66
that the Germans believed the Allies to be planning a largescale
landing in the Bay of Venice, suit that K.G.66 was to be
moved South to take part in a "Total Einsatz" (full-scale
operation) against it. The landing did not, however,
materialise.
8. At the beginning of VON RUNDSTEDT's offensive a number of
aircraft of K.G.66 were detailed to mark an area near Eupen
where paratroops were to be dropped. The operation was kept a
close secret and members of the unit were forbidden to write
home until the flight had been completed. Some of the
paratroops were dropped from Ju.52's of T.G.30; about 100
aircraft in all took part in the mission.
9. A few days later 4-5 aircraft of 1/K.G.66 took off from
Dedolstorf to act as pathfinders for a bomber force in an
attack on some woods to the North of Bastogne which were
stated to conceal a concentration of artillery. They were
accompanied by 3-4 Ju.88 A-4's of K.G.200, the crews of which
were receiving pathfinder instruction from K.G.66.
10. When the K.G.66 aircraft arrived over the target the
weather was very bad with low cloud and poor ground visibility
and as the crews could not identify the target they returned
home with their markers. The crews of K.G.200, however, being
new to this kind of operation, decided to drop their markers
rather than return with them, the result being that the wrong
target was marked.
11. The Kommandeur of I4.1.66 made a complaint to Generalmajor
PELZ and soon afterwards the aircraft of K.G.200 were
withdrawn from Dedolstorf.
12. At about Christmastime some 12 aircraft of 1/K.G.66, six
of them acting as pathfinders and illuminators and the
remainder as normal bombers, flew another sortie to the
Bastogne area. They flew on a course Dedolstorf - Hanover -
Paderborn - Bonn/Mangelar airfield (marked by a searchlight
dome) a light beacon at Trier - a point immediately behind the
German lines, where the starting point of the target marking
run was indicated by Flak star shells. From the latter point
the present crew flew by D/R for about two minutes on a given
course and at a given height before releasing their flares and
ground markers.
TARGET MARKING.
13. The flight to the Bastogne pocket described above gives a
typical instance of the method of navigation used by those
aircraft of K.G.66 which did not employ special navigational
aids. The target marking run was flown on D/R and just before
the target was reached the aircraft began dropping their
flares. Ten of these were dropped in a straight line at tensecond
intervals - i.e. about 1000 metres apart - and laid so
that the centre of the line was over the target. The aircraft
then made a 180° turn, identified the target by the light of
the flares and then dropped coloured ground markers, usually
green, on the target itself.
14. The normal load carried was ten flares and two A.B.250's
containing ground markers. The flares were released from a
height of 2000 metres; they illuminated at about 1200 metres
and burned down to 200 metres above ground.
LUX BUOYS.
15. The Lux buoys used by K.G.66 for minelaying operations
and, as stated in the previous report, used by certain
aircraft of the Gruppe whilst pathfinding for at least one V.1
launching operation, are carried in A.B.250 containers. The
containers can, of course, be released from any height but
they must be fused to open, releasing the Lux buoys, at a
minimum height of 200 metres.
16. P/W said that in very clear weather the Lux buoys could be
seen at a distance of about 20 km. from an aircraft flying at
a height of 2000 metres.
NAVIGATION.
17. As befits a pathfinder unit, K.G.66 treats the question of
navigation as of primary importance during briefing. Full
details of W/T and visual beacons, Sonne, and other
navigational aids are given to the crews at least two hours
before take-off to allow ample time for study, and the
observer of the present crew states that with these aids it is
very difficult to go wrong unless the radio apparatus refuses
to function.
18. If the flight has gone according to plan the operation is
not examined in detail at the subsequent interrogation, but if
anything has gone wrong the latter is investigated very
thoroughly and the observer had to make a full report.
SPECIAL NAVIGATIONAL AIDS.
Egon.
19. It was stated in the previous report that a detachment of
K.G.66, consisting of three crews of the 1st Staffel and four
crews of the 3rd Staffel, was sent about the middle of
November 1944 to Zwischenahn where they were told that they
would have to fly sorties under Egon control in conjunction
with He.111's carrying V.1's.
20. During the first fortnight in December the crews carried
out a certain number of Egon practice flights but the weather
was so bad that the present P/W, who were members of the
party, made only one flight. This was to Texel and the
aircraft experienced severe icing conditions both on the
outward and homeward routes. Possibly as a result of the
aerials icing up they received no instructions from the
ground; on returning to base they were told that the Freya had
plotted them the whole way to Texel and back and had sent them
instruction, but had received no response.
21. The observer states that the usual operational height for
the Egon procedure is up to 4000/5000 metres, at which height
the maximum control range is about 350 km.
"Y" Procedure.
22. The present crew returned from Zwischenahn to Dedolstorf
about the middle of December. Up to this time none of them had
received more than theoretical instruction in the "Y"
procedure, but about a week later on December 20th/21st, the
W/T operator made one flight as a member of another crew
undergoing "Y" training.
23. This flight was from Dedolstorf to Wittenberg, about 100
km. to the E.N.E. The aircraft was controlled from a "Y"
installation at Dedolstorf consisting of one single mast with
a small aerial array at its head of which P/W could give no
exact description. Instructions were passed to the aircraft
over the FuGe 17 and when the ground control wanted to fix the
aircraft the W/T operator of the crew depressed the "Y" key on
his FuGe 17 for five seconds on request.
24. The flight was a failure. The "Y" beam became bent owing,
P/W thinks, to variations in the electric main current, which
fluctuated between 220 and 180 volts, and when the bombing
signal was received the aircraft, although still on the beam,
was at Magdeburg, some 95 km to the South of Wittenberg.
25. The next day the Staffelkapitän of 1/K.G.66 undertook a
similar flight, which was more successful. When he received
his bombing signal he was over Seehausen, only a few km. S.W.
of Wittenberge.
The New "X" Procedure.
26. This new procedure is basically a combination of the "Y"
beam and the Egon procedure. A "Y" beam - referred to by P/W
as "Oskar"; the code name known to have been applied to the
original "Y" beam used in 1940 - is employed in conjunction
with the FuGe 28, the FuGe 25a and a clock which P/W called
the "Y" clock, but which appears from their description to be
similar in principle to, if not identical with, the "clock"
reported in April 1944 as having been devised for the Egon
procedure. (A.D.I.(K) 160/1944).
27. The knowledge of the present P/W on the new procedure was
only derived from theoretical instruction. They had heard
whilst at Zwischenahn in December 1944 that the system was to
be introduced in their Staffel, but there was some delay in
obtaining the necessary apparatus, notably the "Y" clock, and
at the time when P/W were captured on January 23rd, only two
or three aircraft of the Staffel were equipped.
28. P/W themselves had received a certain amount of
theoretical instruction during January but only one of them -
the W/T operator - had seen the "Y" clock. They were to have
received airborne instruction on January 25th and 26th flying
over the North Sea one northerly course from Leeuwarden; it
was thought that the necessary airborne instruction could last
about 8-10 days in all and that early in March aircraft of the
Staffel would be ready to use the new procedure operationally
over the front line areas.
29. The type of "Y" beam station used is described by P/W as a
number of main aerial masts about 10-12 metres high
interspaced with smaller vertical dipoles which radiate one
main beam and a series of about six secondary beams on each
side of it at diminishing intervals, the first being at 13°
from the main beam. The array is located on a large turntable
for directional purposes. P/W stated that two of these "Y"
stations were at Leeuwarden and on the mainland near Den
Helder respectively.
30. For the reception of the "Y" beam the aircraft carries a
FuGe 28, the visual indicator of which is referred to
according to circumstances as "Kommando" or "Anzeiger". When
the aircraft is flying along the main beam to the target the
pointer on the dial gives "Kommando", that is to say when the
pointer indicates left it "commands" that a correction to the
left must be made to return to the beams. When the aircraft is
flying on a secondary beam, however, the pointer is referred
to as "Anzeiger" and "indicates" the position of the aircraft
in relation to the beams. When the pointer indicates left for
instance, the aircraft is to the left of the secondary beam
and a correction to the right must be made to bring it back to
that beam.
31. The reverse holds good when flying back from the target to
base but for convenience the visual indicator can be switched
over for the return flight to indicate in the same way as on
the outward flight.
32. The continuous tone of the secondary beam is undulating
while that of the main beam is level and the difference can be
readily distinguished by the W/T operator. It is usual for the
aircraft to fly along o secondary beam until instructions are
received over the "Y" clock or the FuGe 17 to fly on the main
beam.
33. The "Y" clock indicates by means of radio impulses from
the ground station a previously-arranged series of code
instructions similar to those used in the Egon procedure. Its
great advantage is that it dispenses with almost all R/T or
W/T signals between ground central and aircraft.
34. P/W did not know the FuGe number of this instrument and
none of them, with the exception of the W/T operator, had
heard any other name for it than the "Y" clock; the latter had
once or twice heard it referred to as the SNK-Gerät, but he
had no idea what these initials denoted.
35. The description given by P/W is strikingly similar to that
contained in A.D.I.(K) 160/1944 paras. 29-36. Basically the
clock consists of a cathode ray tube screen about 20 cm. in
diameter with numbers from 0 to 9 spaced at intervals round
its circumference. Each of these numbers denotes a code
instruction, the significance of which is given on the W/T
briefing sheet for each operation and is varied from sortie to
sortie.
36. Numbers 1 to 3 or 4 are reserved for the individual
aircraft and in explanation of this P/W says that at the most
four aircraft would be used as pathfinders proper, whilst
other aircraft in the unit would be used to renew the markers
and flares laid by these four aircraft, flying probably on
Egon or even on D/R to bring them near enough to the original
marking to enable them to correct their course themselves.
37. The remaining numbers, i.e. 0 and 4 or 5 to 9, are
allocated to the respective code instructions, such as
"distance from ground station to aircraft", "distance from
aircraft to target", "height", "change course left", "change
course right", and bomb release warning.
38. The "hand" of the look appears as a wedge-shaped blip on
the screen of the Cathode ray tube about two-thirds out from
its centre. It rests at a neutral position at twelve o'clock
and is moved to the various figures by means of impulses from
the ground station lasting only 1/100th of a second, and
therefore calculated by the Germans to be unjammable by us.
39. There is an aerial in a shallow perspex-covered bola in
the centre of the underside of the fuselage, but P/W could not
describe this array or say whether it was for the "Y" beam
reception or for the SNK-Gerät.
40. During its flight the aircraft keeps its FuGe 25a switched
on and is plotted by ground Radar, which gives any necessary
instructions over the "clock". According to P/W the positions
1 and 2 on the FuGe 25A indicate "Grob-Messung" (coarse fix)
and "Fein-Messung" (fine fix) respectively.
41. The method of working with the new "Y" procedure is as
follows:
The aircraft flies by D/R from its base until it picks up the
secondary beam of the "Y" station, along which it then flies
until instructions are received to move over to the main beam.
The W/T operator has his FuGe 17 switched on ready to receive
any instructions, and the FuGe 25A is switched on in position
1.
42. From time to time signals are received from the ground,
the warning to the W/T operator being a continuous tone of
about 2 - 3 seconds on the FuGe 17 indicating to him that he
is to stand by to receive instructions over the clock. Shortly
afterwards a small white indicator an the top of the clock
lights up and the blip moves round from the neutral position
at 12 o'clock to one of the numbers between 1 and 4 indicating
the particular aircraft being called. After stopping at the
number for a second or two only, the blip returns to the
neutral position.
43. The message for the particular aircraft called then
begins. If the instruction, for instance, is "change course to
the right by 15°", the blip will first move to the number
allotted to "Change course right" and then in turn to the
numbers 0, 1, 5, indicating 015°, returning to the neutral
position after each individual number, Acknowledgment of the
message is made by switching the FuGe 25A off and on again. If
this is done instructions are continued if necessary, but if
no acknowledgment is received by the ground control, the
instruction is repeated until acknowledged with the FuGe 25A.
44. Should the aircraft wander owing, for example, to
disturbance of the beam, fresh instructions are sent from time
to time by means of the clock. Shortly before the target is
reached, instructions are received via the "clock" to switch
over to position 2 on the FuGe 25A for a fine fix on the last
run to the target.
45. One minute before the actual target is reached the W/T
operator receives his standby warning on the FuGe 17 followed
by the appropriate code number on the clock denoting that the
markers or flares must be released in 60 seconds time. The W/T
operator or the observer then "stops" this time on his watch,
but the flares or markers are not-released until a red lamp
lights up above the clock; this may be a little short of 60
seconds or a little longer.
46. The bomb release signal could also be given over the FuGe
17 instead of over the clock. The method in this case would be
that at the beginning of the 60 seconds a morse signal such as
-. would be given and then when the time of release was
reached a further -. , the flares being released on the final
dot.
47. The clock is usually placed in front of the observer so
that he can acknowledge signals with the FuGe 25A, which is
also situated within his reach.
48. Although two or three aircraft of 1/K.G.66 are at present
fitted with SNK, it is the intention to fit all aircraft of
the Staffel with this new apparatus. The aircraft retains,
however, its normal radio equipment, so that it can operate
with either Egon or the new "Y" procedure as required. The
aircraft were flown from Dedolstorf to Celle for the fitting
of the SNK.
FuGe 217. (Radar).
49. The Z6 + FH was fitted with a FuGe 217. The crew had
little practical experience with it - they had used it on only
one sortie, in the course of which nothing was picked up - and
they appear to have had rather inadequate instruction in its
function, but they were able to give the following description
of the apparatus.
50. The FuGe 217 differs from the FuGe 216 in both the display
and the aerials. In the FuGe 217 the display is horizontal
across the middle of the screen and through the centre of it
runs a vertical white line which represents zero. The return
from the aircraft itself shows on both sides of this middle
white line, whilst the blip from the enemy aircraft shows on
one side or the other.
51. The range runs to both left and right, with an extreme on
either side of 8 km. The exact object of ranging from the
middle is not known to P/W and they can only suggest that it
may be to indicate whether the aircraft approaching from the
rear is to the left or right.
52. The W/T operator states that the crew had had this
apparatus explained to them merely as equipment for searching
to the rear and had never heard of it in connection with
D/F'ing, although having a vertical line in the centre of the
screen with display on both sides of it would indicate that
perhaps it could be used for this purpose.
53. Although the screen is calibrated up to 8 km, the actual
maximum range at K.G.66's normal operational height - some
2000 metres - is only about 4 km, as this is the distance on
the display between the return from the parent aircraft and
the ground return; the observer assumes that the minimum range
at which an aircraft can be identified is about 500 metres,
but it may be a little less.
54. Below the screen are three control knobs for focus,
brilliance and range; the latter has two positions, one for a
coarse setting giving the 8 km, range, and the other a fine
setting for a range of 4 km.
55. There is an aerial array above each wing surface; that on
the starboard wing, P/W believes, is the transmitter, and that
on the port wing the receiver. The main support for each array
protrudes rearward from the wing surface at an angle of about
35° from the horizontal, at a point about a quarter of the way
inboard from the wingtip and just forward of the aileron.
56. Running upwards from the main support, at a slight angle
to the vertical, are three feeders, each with a horizontal
dipole at its tip, extending about 15 cm. to either side of
the feeder. The feeders are staggered in length, the forward
one being highest and the aft one lowest; the latter is almost
directly over the trailing edge of the wing.
57. During lectures on FuGe 217, the instructor had drawn the
lobe of search and P/W says that whereas in the FuGe 216 this
was to the rear and downwards, in the FuGe 217 it was to the
rear and above the aircraft, with the deepest point only some
400 metres below the aircraft itself.
58. The explanation of this may be that the operations carried
out by K.G.66 were mainly those entailing a low flying height
- anything from ground level up to 2000 metres - and therefore
any contact by night fighters would be free the rear above
rather than below. The angle of search is about 30° from the
centre on each side, and there is a small lobe of search,
probably about 1 km, to the front of the aircraft.
59. Crews are not enthusiastic about the FuGe 217 and the
present one, although it had been flying several months with
it, had only once used it on one sortie, mainly because when
they switched it on it disturbed the whole of the radio
equipment in the aircraft. Not only the intercom, but also
ground signals over the FuGe 17 or FuGe 10 are upset, and it
also makes D/F'ing extremely difficult. Apart from this, P/W
also believe that the radiations facilitate the work of our
airborne search equipment.
JU.88 S-3.
60. The Z6 + FH, a Ju.88 S-3, was fitted with Jumo 213
engines. The crew are very enthusiastic about this aircraft
and state that with the Jumo 213's it has the following speeds
at about 2000 metres:-
2300 r.p.m............ 380 k.p.h. A.S.I. without bombs.
370 k.p.h. " with bombs.
2400 r.p.m............ 390 k.p.h. " without bombs.
380 k.p.h. " with bombs.
2700 r.p.m.(highest... 440 k.p.h. " without bombs.
cruising speed) 430 k.p.h. " with bombs
61. They themselves had never exceeded 440 k.p.h. and in fast
they usually flew with 2300 r.p.m. The rate of climb was
stated to be 8 metres per second with bombs at 270-280 k.p.h.
A.S.I. and 15 metres per second without bombs at 240-250
k.p.h.
PERSONALITIES - 1/K.G.66.
62. Oberleutnant HANSEN is Technical Officer of the Gruppe.
63. 1st Staffel.
Staffelkapitän Oberleutnant PIOTA.
Ia.(Operations Officer) Oberleutnant HEBERSTREIT.
N.O.(Signals Officer) Leutnant KUBLER.
64. The following are crews in the 1st Staffel:-
Pilot: Oberleutnant PIOTA. Leutnant ALTROGGER.
Observer: Unteroffizier SEMPF. Feldwebel HERMANN.
W/T: Unteroffizier KONNER. Oberfähnrich GRAUENHORST.
Pilot: Leutnant KUBLER. Oberleutnant TRAUBER.
Observer: Feldwebel MALLY. Fähnrich SCHNEIDER.
W/T: Unteroffizier SCHMIDT. Feldwebel BEHRENS.
Pilot: Stabsfeldwebel FISCHER. Feldwebel HOFSTELLER.
Observer: Oberleutnant HEBERSTREIT. Unteroffizier VOGEL.
W/T: Stabsfeldwebel BACHMANN. Feldwebel NIED,
Pilot: Oberfeldwebel JACOBS. Unteroffizier KELLER.
Observer: Oberfeldwebel JAGLA. Unteroffizier SCHONFELD.
W/T: Unteroffizier BINGEL. Unteroffizier SILKE.
65. Stabsfeldwebel FISCHER, who pilots Oberleutnant
HEBERSTREIT the IA of the Gruppe, is in the Stabstaffel but is
attached to the 1st Staffel.
66. Oberfeldwebel LEHR, a pilot in the Staffel, has gone off
to the Luftkriegschule and will shortly be returning as a
Leutnant. His W/T operator Feldwebel TOMASCHEK is at present
without a crew.
67. Oberfeldwebel SIEMER has left the 1st Staffel and is now
in the Kriegsschule; it is not known if he will return to the
Staffel.
68. Apart from the above, three new crews with an
Oberleutnant, an Oberfeldwebel and an Unteroffizier as pilots,
names unknown, arrived a few days before the present crew was
shot down.
2nd Staffel.
69. The following are pilots in the 2nd Staffel:-
Oberleutnant GUSZ.
Oberleutnant MADETZKI.
Unteroffizier ROTGANGEL.
Feldwebel ROTH.
70. Oberleutnant GUSZ is the Staffelkapitän; his observer is
Unteroffizier ULLRICH.
3rd Staffel.
71. The following are members of the 3rd Staffel:-
Pilot: Leutnant BERCHTOLD.
Observer: Unteroffizier GRUNEL.
W/T: Oberfeldwebel KURZ.
Pilot: Oberleutnant MEHLS.
" Leutnant HINZ.
" Gefreiter KANDZORA.
Losses.
72. The following were lost during the operations over the
Bastogne pocket:—
1st Staffel - Oberfeldwebel SCHMALZBAUER.
3rd Staffel - Fähnrich TULLNER.
Oberfeldwebel MOTZ.
Leutnant SCHUBERT.
73. The W/T Operator of the last named was Feldwebel LABINSKI.
K. G. 54.
74. It has been stated earlier in this report that prior to
joining K.G.66 this crew, had been in II/K.G.54. In December
1944 one of them met a friend from his old unit who told him
that II/K.G.54 was in process of converting to the Ar.234.
Unfortunately, no further details were available.
A.D.I.(K)&
U.S. Air Interrogation. S.D. Felkin,
19th February 1945. Wing Commander."

Bruce

"SECRET A. D. I. (K) Report No. 357/1945.
THE FOLLOWING INFORMATION HAS BEEN OBTAINED FROM P/W. AS THE
STATEMENTS MADE HAVE NOT AS YET BEEN VERIFIED, NO MENTION OF THEM.
SHOULD BE MADE IN INTELLIGENCE SUMMARIES OF COMMANDS OR LOWER
FORMATIONS, NOR SHOULD THEY BE ACCEPTED AS FACTS UNTIL COMMENTED
ON IN AIR MINISTRY INTELLIGENCE SUMMARIES OR SPECIAL
COMMUNICATIONS.
RADIO AND RADAR EQUIPMENT IN THE LUFTWAFFE - II
Navigational Aids.
1. This report is the second of the series dealing with radio and radar equipment in the
Luftwaffe.
2. As in the case of the first of the series (A.D.I.(K) 343/1945) dealing with Blind Landing
and Airborne Communications Equipment, it is based on interrogation of General
Nachrichtenführer MARTINI, Director General of G.A.F. Signals, and a few important
members of his staff, and has been supported by a file of current papers which were in the
possession of the General’s Chief of Staff.
3. An index of the numerical designations of the navigational equipment mentioned in this
report appears in Appendix I.
4. For convenient reference, a translation of the document entitled "Funkausrüstung der
Flugzeugmuster, Notprogramm" (signal Equipment in the G.A.F. - Emergency Program) - item
45/99 ff in A.D.I.(K) Documents List 45/9 - which has also appeared as an Appendix to
A.D.I.(K) 343/1945, is reproduced as Appendix II to the present report but the list of equipment
contained in that document has been omitted as Appendix I gives a fuller list.
TRENDS OF DEVELOPMENT.
5. Throughout the course of the war, the general standard of German navigational training was
undoubtedly inferior to that of the Allies. A simple form of navigation was taught but
navigators track plotted only and relied on W/T aids and in particular positioning by means of
loop fixes as the main basis for their navigation.
6. During the early part of the war extensive use was made of Knickebein and other beam
systems, but later this form of navigational aid gave way to the "Y" control system (better
known by the Allied codeword Benito) and "Egon".
7. Sonne was universally accepted as an outstanding success and from the time of its inception
in 1942 research was continuously directed towards overcoming its imperfection, in particular
the range limitation. Komet was a typical example, of attempted improvement on these lines
8. The Germans were patently backward in the field of pulse systems and the majority - if not
all - of their navigational aids of this type were copied from Allied methods.
9. The fear of the Allied countermeasures was much to the fore during the last two years and
considerable research and efforts was devoted to offsetting such interference and to perfecting
systems which would reduce and if possible preclude the danger of jamming. Another factor
always present in the minds of those responsible for tactical navigational requirements was that
the apparatus must be as light and small as possible because of the limited space available in
German aircraft.
10. During the last stages of the war, and as a natural consequence of German air policy, being
forced to concentrate on the defensive, thereby involving almost exclusive use of fighter power,
a great deal of attention was devoted to the development of simple navigational aids suitable
for single-engine aircraft of which Rübezahl was a typical example.
D/F LOOP EQUIPMENT.
PeGe (Peil Gerät) 6.
11. PeGe 6 was the successor of PeGe 5, the standard loop D/F, set in use at the beginning of
the war, and. operated on 150 - 1200 kc/s (2000-250 meters). It provided automatic D/F
facilities, the W/T operator merely having to tune to the signal and the "answer" being produced
on a course indicator.
12. In the opinion of P/W, who was responsible for operational requirements in the
navigational field and who had had fairly extensive navigational experience with K.G.40,
PeGe 6 was less reliable than the manually-operated PeGe 5 as the automatic D/F facilities
could not distinguish between the true signal and jamming and were apt to record bearing midway
between the two if they were near together. The human ear was much more acute and
could distinguish the minimum of the real signal from that of the "phoney” one. It had the
further disadvantage that it was a heavier piece of equipment than the manually operated set.
FuGe 141
13. The FuGe 141 operating on a frequency band of 58.0 - 59.2 mc/s was a receiver with a D/F
loop fitted to Air Rescue aircraft used for homing on to the NS 4 emergency radio set carried on
the chest by pilots.
14. The NS 4 had a flexible steel tape aerial and batteries which gave it an endurance of 2 to
2,5 hours.
FuGe 142.
15. The FuGe 142 using the 2000 - 250 metre band was a small D/F battery set for use in
emergency in the event of failure of the aircraft' s electricity supply.
16. The FuGe 142 had a manually-operated loop and its accuracy was only 10° to 15°.
17. When the P/W who, in October 1944, took over the navigational tactical requirements first
made its acquaintance, he discovered that the designer of the emergency set, while having the
laudable object of assisting a crew in dire emergency when they where probably well and truly
lost, had omitted to include any sensing arrangement. The set was, therefore, quickly scrapped
as being as much of a danger as an aid.
FuGe 145
18. The FuGe 145 was a simple type of D/F set in development for use in single-seater aircraft.
It was for use with M/F beacons and was designed for use by coastal reconnaissance aircraft, as
for example the Do.335, so that they could obtain a bearing when flying at low level.
19. It was much lighter than the PeGe 6 and had no automatic facilities, but was very easy to
operate. P/W had thought that it might ultimately supersede the PeGe 6 for other types of
aircraft.
Suggested loop for fighter aircraft
20. The research centre at Rechlin had been asked to examine a rough type of loop for singleseater
fighter aircraft, which would consist of a loop built into the pilot' s helmet. It was thought
that this would enable the pilot to establish the general direction of a beacon by movements of
his head and without recourse to the use of a compass.
21. This idea was tried out and seemed promising, but was never fully developed.
HOMING BEACONS.
Schwanboje.
22. The Schwanboje was a waterborne V.H.F. beacon dropped by parachute and originally
used by K.G.40 for marking convoys or submarines. In the autumn of 1944 a 1ine of Schwan
buoys was used to aid the He.111's when launching V-1’s from the North Sea against this
country.
23. The beacon consisted of a frame aerial and transmitted on a wavelength which could be
homed on by the FuGe 17, the standard equipment of K.G.40 in 1942 when the Schwanboje
came into use.
24. The set was powered by accumulators and had a live of five hours; by the means of a
clockwork device it could be pre-set before release so that it ran for a testing period
immediately on release and later started up again after a prescribed interval governed by the
expected time of arrival of the homing aircraft. The buoy was fitted with a self-destroying
charge operated automatically.
25. A later type of Schwanboje operated on the 38 - 42 mc/s waveband so that aircraft
equipped with the FuGe 162 could also use the system.
Biene
26. Biene is the code word for a responder beacon. The idea of responder beacons for homing
purposes had only been hit on in 1944 and Bienen to respond to the different airborne radar sets
were still under development in 1945. The FuGe 243 - Hohentwiel Biene – had been used by
coastal units in Norway, in February or March 1945.
27. Responder beacons were also being developed for use in the Baldur method of navigation
(see paragraphs 79, 82 of this report).
BEAM SYSTEMS.
Zyklop.
28. This was the latest form of the well-known Knickebein working on 30 - 33,3 mc/s and
received by E.B.L.3 in the aircraft. It was a mobile station which could be fully erected into
operation within a week.
29. A still more mobile unit known as the Bock-Zyklop had been introduced. This could be set
up in three days and could be adapted for use on the FuGe 16 frequency although as yet,
according to documents, no visual indicator for the FuGe 16 had been developed.
30. The 120 W ground transmitter was called the ???? which gave a beam 0.5° wide and a
range of 300 km. at a height of 5,000 meters. The Zyklop systems had been made use of on the
Russian front up to the end of the hostilities.
Sonne.
31. The Sonne beacon system which worked on a frequency of 270 - 480 kc/s was received in
the aircraft on the FuGe 10. It was considered an extremely effective daylight system but the
range limitation was a disadvantage. Fixes could be obtained from ranges up to 1,000 - 1,200
km. Sonne 6 at Quimper which was the most efficient of the Sonne beacons, had been used on
an occasion at a distance of 1,400 km.
32. The sectors served by Sonne covered, an angle of 120 – 150°. The beacon was very reliable
over the centre sector of 100°, but the error increased progressively towards the edges of the
beam in conformity with the sine law.
33. At night errors up to 4° were liable to occur even in the centre of the sector of the beacon
and no real use could be made of it.
Mond.
34. To improve the Sonne beacons both in range, and accuracy, an experimental system
working on the same principle, but on 3000/6000 kc/s was tried out in 1942. The shorter wave
transmission did not prove very reliable and was given up about the end of 1943.
Stern.
35. Finally a beacon of the Sonne type under the name "Stern" was designed for use on a V.H.
frequency. It, not unnaturally, only gave optical range and was, therefore, of no practical value
and was not developed.
Dora.
36. One P/W had seen documentary mention of Dora which he believed was a navigational aid
system and a precursor of Komet. He did not know whether it worked on the same principle but
the Komet experimental site at Kolby was on the former Dora site.
Komet.
37. In 1942 the question of navigation over the Atlantic stood in the limelight . As the He 177
was supposed to be coming into service shortly to enable K.G.40 to reach further West, the
need for navigational equipment of longer range became acute.
38. A year or so earlier Professor von HANDEL had categorically stated in a lecture that a
long-range navigational system based on pulse would inevitably be extremely inaccurate.
In view of Professor von HANDEL's views on pulse systems, an improved form of Sonne
which would give much greater ranges and be less susceptible to night effect was given high
priority.
39. The system evolved was called "Komet" and experimental stations were erected at
Bordeaux and Kolby (see A.D.I.(K) 364/1944). The ground station called for an array of no less
than 127 masts and 19 control huts in order to cover a 90° sector. It worked admirably provided
a 10° sector only was covered, but as soon as the planned 90° sector was put into operation,
mutual interference between the masts arose and the various lobes radiated were no longer of
symmetrical pattern, with the result that large errors crept in.
40. Research on this delayed the project considerably. After the invasion when long distance
reconnaissance in the Atlantic was no longer practical politics, the Komet system was given up
without ever having been effectively used. The development people were the more pleased to
dispense with it since it left the German radio research and industry free to deal with other more
urgent matters.
41. The beacon was to operate on frequencies of 5000, 9000 or 12,000 kc/s received on the
FuGe 10K, and it was estimated that ranges up to 3000 km would be obtained. The system
employed was to be similar to that used in the Sonne but instead of obtaining one reading per
minute, oscillation of the beam was to be speeded up to give 100 readings par minute.
42. The true bearing of the aircraft was automatically recorded by the FuGe 124 which was
known as the Kometschreiber. The recording took the form of a series of vertical lines, one for
each reading, printed on a strip of paper. At the same time as the lines were printed the
Kometschreiber recorded the section of the swept area in which the aircraft was flying, thus
giving what amounted to a rough position.
43. The fine reading was obtained from the length of the recorded lines. Any inaccuracies due
to night effect could be easily eliminated by averaging the length of the lines, as recorded, on
the paper strip, by eye.
Erika.
44. Erika was a navigation system (see A.D.I.(K) 364 and 409/1944.) which had already
reached the development stage in 1942 but its operational employment was of brief duration
and it was soon discarded in favour of Bernhard.
45. Erika was based on the principle of a V.H.F. (30 - 33 mc/s) beam oscillating rapidly over a
segment of about 60 – 90°. The beam was phased, a different phase being picked up in different
sections of the segment and read off in relation to a standard phase producer in the aircraft. In
order to obtain a fix, two such Erika stations had to be received and to receive each station no
less than two E.B.L.3's were necessary making a total of four receivers.
46. The range presentation unit in the aircraft, FuGe 121, took the form of a clock-face with a
needle indicator and calibrated, P/W thought, from 0 -100. A specially prepared map was
required to establish bearing.
47. A disadvantage of Erika was the vulnerability to jamming, interference signals modifying
the phase and thereby giving inaccurate readings. The great weight, carried and the bulk of the
four receivers, which were particularly cumbersome in the relatively small aircraft in use in the
G.A.F. made its widespread use impracticable.
Bernhardine.
48. This system was first introduced in 1942 for use by bomber aircraft, but was later dropped
in favour of the Benito and Egon control systems. With the increasing British jamming during
night raids it was reintroduced for use in night fighter commentary (see A.D.I.(K) 125/1945,
paras.5 to 29), which it was thought could only be jammed with great difficulty.
49. The term “Bernhard” was used for the ground stations whilst the airborne recording
equipment was called Bernhardine or FuGe 120. The latter made use of the E.B.L.3. receiver as
the transmissions lay in the 30-33 mc/s band.
50. At the time of the German capitulation, the following three transmitting stations were in
operation, the first two, of which could transmit commentary.-
-Thisted, on N.W. coast of Denmark.
-Bretstedt, N. of Husum, Germany.
-Trebbin, S.E. of Berlin.
51. A further station near Breslau had been almost completed when it had to be dismantled on
account of the Russian advance. Additional stations were in the course of construction near
Kassel, Munich, Pilsen and Vienna.
52. The Bernhardine system was looked upon as a considerable improvement on Erika. It gave
360° coverage as compared to 60/90° with Erika and, whereas from the jamming aspect stray
signals could disturb the phase of Erika causing false indication, in the case of Bernhardine,
interference merely resulted in no reading being possible, and furthermore to attain this through
360° a very powerful jamming transmitter flying near the ground station would be needed.
53. The Bernhardine system was not regarded as unjammable but it was thought that use of
high power and aerial gain would render jamming by airborne means impracticable.
54. In addition to the E.B.L.3 receiver, the airborne Hellschreiber FuGe 120, also called the
Bernhardine, which gave both bearing and commentary was employed. According to P/W the
FuGe 120 was large and weighty and the first improvement aimed at was to reduce the weight
and provide a set which occupied less space in the aircraft. To this end an attempt was made to
eliminate the use of paper strip for the Hellschreiber and a rotating "Folienschreiber" a
cellophane paper moving over a sticky carbon surface which constituted a self-eraser - was
employed. This projected recording method proved a failure and the use of paper strip had to
be reverted to. According to documents the type using paper strip was known as FuGe 120a,
and the self-erasing recorder FuGe 120b.
55. A smaller model, the FuGe 120k, to operate on the paper strip principle which constituted
the latest improvement, was still in the development stage at the conclusion of hostilities.
Previously the ground transmitter broadcast simultaneously from the upper and lower aerial
arrays on two frequencies close enough to one another for them both to be received on one
channel of the E.B.L.3. One lobe was used for coarse D/F, the other for fine. The two
frequencies were then separated by a filter before being fed into the Hellschreiber. The FuGe
120k was designed for use with a ground transmitter operating only on the coarse D/F
frequency. The filter could therefore be dispensed with and considerable weight saved in the
airborne set at the expense of some accuracy in D/F.
56. With the loss of D/F accuracy the sharp “V” in the vertical printing indicating the reading
(see diagram A.D.I.(K) 125/1945 para.18) became a gap about 4° wide. To facilitate the
reading of the centre of the gap by eye, and to reduce the size and weight of the apparatus, the
vertical lines referred to above were superimposed on the scale which could then only be read
in the gap. This allowed the paper strip to be considerably narrower.
57. The FuGe 120k was designed primarily for use in single seat jet aircraft but was also to be
embodied in the Ju.88 where space was at a premium, as soon as sufficient numbers of this set
were available.
Hermine.
58. The Hermine system was originally developed, in response to a tactical requirement
formulated during the second part of 1942, as a navigational aid for the purpose of giving an
approximate bearing to single-engine night fighters engaged on “Wilde Sau” operations.
59. By the time the initial difficulties in development had been overcome Wilde Sau night
fighting had almost ceased; it was found however that Hermine could be used to advantage by
day fighters, and it came into operational use.
60. An accuracy of ±5° was assumed, but it was found in practice that this could be improved
upon to ±3° by experienced pilots.
61. Thirteen or fourteen ground stations were in operation by Easter 1945 which, P/W claimed,
gave complete coverage of the Reich. It was intended to fit two Schlechtwetter (bad weather)
Fighter Geschwader with the necessary airborne equipment, and this program had been onethird
completed by May 1945. One P/W had heard that ten to fifteen Me.262's of K.G.51 were
amongst the aircraft so equipped.
62. The following may be added in modification of the description of the Hermine system
given in A.D.I.(K) 125/1945, paras.59 to 62. The Hermine rotating beacon transmits a
continuous tone on which is superimposed a speaking clock which counts from 1 to 35, each
figure representing tens of degree. Over an angle of about 15° the continuous tone falls to a
minimum and rises again. During this period the voice appears to become more audible and the
pilot can estimate where the minimum of continuous tone occurs, and so obtain his bearing
from the beacon.
63. The beacon recognition is given by means of a self-evident code name for example,
"Berolina” for Berlin – which is spoken by the voice in place of 000°.
64. The airborne equipment is the FuGe 125 consisting of the E.B.L.3 with the Tzg
(Telephoniezusatzgerät) which enables the 30.0 - 33.3 mc/s transmission picked up on the
E.B.L.3 receiver to be heard in the pilot's headphones. Though the Hermine beacons were fully
operational there was a scarcity of FuGe 125 sets, as a result of which practical experience of
this system was too limited to judge of its efficiency or to lead to further improved tactical
requirements been formulated.
PULSE SYSTEM.
Ingolstadt
65. All the P/W had heard reference to Ingolstadt and agreed that it was a long-range
navigational system.
66. One P/W thought that Ingolstadt was the cover name for a pulse navigation system using
hyperbolic curves and similar to British Gee; it was originated by Telefunken in 1938 but was
then turned down by the R.L.M. In his recollection the original Telefunken idea derived from
theoretical discussions at an international conference before the war.
67. As mentioned earlier under the heading of Komet, Professor von HANDEL maintained that
owing to the incidence of mutual interference between direct and reflected waves the system
was impracticable at long range. In consequence of von HANDEL’s view the system was
dropped.
68. Much consternation and annoyance was occasioned in 1944, when it was found that the
Allies were successfully operating a similar system.
69. Truhe is the cover name used to describe navigational aid system, using ground stations,
similar to those of British Gee. In effect the British Gee stations were also used, the airborne
sets being almost identical with the British Gee boxes.
Truhe.
70. There is no very distinct difference between "Truhe" and "Hyperbel". The latter term was
originally coined to denote our Gee. It was also used when German aircraft equipped with
British Gee sets made use of British ground stations.
71. The British Gee chain was used successfully but it was realised that so soon as the
Germans lost an aircraft, over England, a change would be made. The German "Y" service
monitored the British ground stations to follow any change in Gee phasing and passed advice of
such change to their aircraft by W/T.
72. Truhe referred to the German system which was ultimately to cover the 20 to 100 mc/s
band and employed various types of ground transmitters including Feuerhilfe, Feuerstein,
Feuerzange and Feuerland. All these transmitters could also be used to jam our own Gee,
further details of which will appear in a subsequent report on German Radio Countermeasures.
The original 46 to 50 mc/s system was known as Truhe I and the new 30 to 60 mc/s system as
Truhe II.
73. A chain of Truhe stations was built around Berlin, primarily for training purposes and there
were in addition groups of ground stations in the Schwarzwald and in Pomerania. The last
named was intended for operations against Russia and it is not known if the stations were
destroyed before their capture.
74. The airborne sets which were known as FuGe 122 covering 46-50 mc/s and FuGe 123
covering 25-75 mc/s were replicas of the British Gee boxes and according to P/W were
equivalent to British R.1324 and R.1355. These German sets were slightly smaller and more
compact than the British sets.
75. Truhe was used by F.A.G.2 and K.G.66, but up to the time of capitulation only a few
FuGe 122 and FuGe 123 sets had been produced and only one R.F. box for the latter set.
Baldur.
76. The Baldur range-measuring system is comparable to the British G.H. and appears to have
been imitated from it. It was referred to by P/W as “Egon in reverse" and was the only
navigational system developed by the German by means of which an aircraft could measure
distance from a known source as opposed to fixing itself by a position line. As the G.A.F. staff
were still thinking in terms of a grandiose bomber policy as late as June 1944, it was intended
for use by bomber aircraft for pinpointing targets and for accurate blind bombing.
77. The wavelength employed was in the neighbourhood of 2-4 meters and fell in the SN 2
band.
78. Only two experimental transmitters, both located in Lower Silesia, were erected and one
P/W maintained that this system never progressed beyond experimental trials by the
manufacturers. It was eventually relegated to low priority owing to the virtual cessation of
German bomber operations and the pressure of more urgent demands on radio research and the
radio industry.
79. The airborne equipment was known as the FuGe 126 which was made up of a transmitter to
interrogate a ground responder beacon, a receiver and a presentation unit. The receiver and
transmitter were SN 2 units, though P/W thought they might have been slightly modified for
use with Baldur.
80. From documents, the presentation unit appears to have been a modification of the
Würzburg range measurement tube, and the accuracy is given as ± 100 meters at all ranges, but
this was thought to be purely theoretical and P/W doubted whether it would have been possible
to achieve this accuracy in actual practice.
81. A smaller airborne set, the FuGe 126k (k = klein = small) was built for use by single-seat
aircraft. In reducing the size and weight of the set, and making it pilot-operated, accuracy had
to be sacrificed. P/W, who was responsible for putting up the tactical requirements, considered
a clock-face presentation to be the ideal solution. It was expected that the accuracy of the
FuGe 126k would then be of the order of 500 meters independent of range.
Baldur - Truhe
82. It was planned to experiment on a combination of Baldur and Truhe (Gee) for use by
bombers. The intention was to use a hyperbolic grid line of Truhe for the target approach. This
could be pre-set, and the pilot could fly along it by keeping the blip centralised, and could
ascertain his exact position along the line by measuring his distance from a Baldur beacon. This
system was considered simpler particularly for a single-seater aircraft, than the method of using
two hyperbolic grid lines or two distances from Baldur beacons. The first experimental sets
were to be ready in the autumn of this year.
Baldur - Bernhardine
83. A further project was a combination of Baldur and Bernhardine to give simultaneous
bearing and range. The range indication was to be obtained by the pilot pressing a knob when
the range would appear in kilometres on a dial. This system was suggested for use by both day
fighters and bombers.
GROUND CONTROL SYSTEMS,
Benito.
84. The Benito system of control using FuGe 16, known to the Germans as "Y", is too well
known to warrant description. The following paragraphs deal with recent developments.
85. When operating the bomber Benito procedure with the narrow beam. (0.3°) essential for
azimuth accuracy, it was easy for the bomber pilot to get on to one of the side lobes in error
since these were only about 3° from the main beam.
86. In order to minimise the possibility of mistake and to relieve the pilot of the strain of flying
on a beam, an automatic device, the FuGe 28a, was in use which was the improved and final
form of the old Y-Gerät of 1941. Documents dated about June 1944 show that it was used in
conjunction with FuGe 17, but P/W thought that it had been modified for use with FuGe 16ZY
as well.
87. The procedure was that the bomber pilot flew on instructions conveyed over the FuGe 17
until it had been established by ground D/F stations that he was on the true beam, when the
code word "Bako" would be given whereupon the pilot would switch on the FuGe 28a which
took over control of the automatic pilot and kept him on the beam.
88. P/W gave the accuracy of range measurement with the Bomber Benito procedure as only
± 1 km. at maximum range.
Egon.
89. The original Egon procedure which involved the use of two Freyas, the one for rough
positioning and the other for fine positioning - later became known as "Egon Einstand" (One
location) to differentiate from an improved system termed “Egon Zweistand”
90. Egon Zweistand was evolved to offset the inaccuracies in azimuth D/F, and cash in on the
range accuracy of radar. With Zweistand a third Freya was introduced, placed some
considerable distance from the other two Freyas in order to give a distance cut. It was intended
for use by bomber aircraft operating over England or on long range sea missions.
91. The original Zweistand system, which was first tried out in Italy by a Schlacht unit, was
somewhat primitive in that the readings from the extra Freya were telephoned through to the
plotting centre and worked out before being plotted on the Seeburg table.
92. To eliminate the delay thereby involved a landline connection was introduced to feed the
Freya pulse to the C.R.T., which then had two blips showing ranges from the two Freya sites.
The vulnerability of landline to disturbance and destruction later led to the development of a
W/T transmitter and this method was employed successfully in operations.
93. Since the Freya pulse was not strong enough to trigger off the FuGe 25A at ranges
exceeding 250 kilometres, it was planned to supplant the Freya by extra powerful
Wassermanns, and thereby increase the effective range of Egon Zweistand to 350 kilometres.
94. A further line of development was the provision of a new type of control table giving the
exactitude of plotting necessary for pinpoint bombing. This control table, which was under
development at Rechlin, made use of complicated mechanical apparatus for accurate projection
of the position of the bomber. One of these tables was destroyed in the course of a daylight air
attack on Rechlin in February 1945; two other tables were in existence at the time of the
capitulation, and were located somewhere in Western Germany.
95. Egon when first introduced was received with some scepticism by the crews, as it was felt
that it was too vulnerable to jamming. After it had been used operationally without being
jammed in the attacks on London in March 1944, the procedure was adopted with greater
confidence, and it gained a good reputation. As recounted in A.D.I.(K) 343/1945, Egon was
always favoured by the R.L.M. technical development section in preference to Benito control.
96. A drawback of the system was its restricted range at low altitude, which according to P/W
was the reason why it was not used in conjunction with V.1 operations.
Nachtlicht
97. The Nachtlicht system was the first method of control not using R/T speech to be
improvised by the Germans, and had been tried out during the raids on London in the spring of
1944.
98. It had been observed that the red signal lamp of the FuGe 25A was illuminated when the
aircraft was being swept by a Freya, and it was suggested that use could be made of this as a
means of transmitting morse signals from the ground. A Freya operating on a special
wavelength, which P/W thought was 2.55 meters, was set up on the Channel coast and was used
to send simple instructions to the aircraft attacking London by means of visual morse
indications on the lamp of the FuGe 25A.
99. The primitive method of giving distant control indications was the forerunner of
"Nachtfee", "Barbara" and "Barbarossa".
100. Luftkurier was the first development of the Nachtlicht idea. It was primitive device
intended to give visual indication to the pilot by means of a pointer which was started and
stopped by the reception of pulses.
101. P/W thought that Luftkurier was first tried out by K.G.66 on the Freya band, but it was so
easy to jam by the addition of extra pulses that it was never developed.
Nachtfee
102. Nachtfee was the term used to describe a system for the transmission of control
instructions to a pilot in the beam of the controlling Freya through the medium of a C.R.T.
indicator similar to the Lichtenstein range tube. The airborne equipment used was known as
FuGe 136 and weighed 12 kg.
103. The original purpose of Nachtfee was, to provide a solution to the jamming of R/T control
systems, and it had been used operationally by the Pathfinders of K.G.66 for mines in the
Scheldt estuary. It was to be adapted for use by night fighters to overcome our jamming of the
night fighter commentary.
104. Nachtfee was a system using the FuGe 25A as receiver.
105. The presentation screen in the aircraft was inscribed with various commands both on the
inside and outside of a circular time trace. There was a stationary zero blip in the 12 o'clock
position, and when an instruction was radiated the pulses received caused a second blip to
emerge from the first and travel round the C.R. tube in a clock-wise direction, presumably by a
slight change in p.r.f. This blip came to a stop and the command corresponding to its position
could be read off on the inside of the time trace where a total of about eight different
instructions were inscribed. It took from one to two second, for the blip to travel round the
tube.
106. It was thought that the further eight commands inscribed on the outside of the time trace
were denoted by the blip making a complete circle starting round a second time before coming
to rest at any one of the eight sectors. In this way a total of sixteen different orders could be
given. For night fighters such instructions as "turn left/right", "climb", "dive”, etc. appeared on
the inner side and figures for transmitting bearing on the outer side of the trace.
107. This system was used operationally, but it was found that, apart from the susceptibility to
jamming, other pulse transmissions could interfere by unlocking the system and thereby cause
wrong positioning of the indicator blip.
108. Another pronounced objection to the Nachtfee lay in the fact that it was necessary for a
member of the crew to watch the C.R.T. indicator uninterruptedly for missing one blip
indication might give the message a false value. It was not therefore possible to use it in singleseater
aircraft.
Barbara
109. This apparatus, also called FuGe 138, consisted of an attachment to the FuGe 25A
receiver and only weighed 2 kg. This unit contained an audio filter which allowed the pilot to
hear morse signals superimposed on the Freya interrogator transmission if they were emitted on
a suitable audio frequency usually about 800 cycles. By keying other morse signals on different
audio frequencies and equipping aircraft with suitable filters, more than one aircraft could be
controlled by a single Freya.
110. Barbara was to be used for Egon control of ground-strafing aircraft and bombers but not
for night fighters.
111. In the Germans' opinion there were three disadvantages, namely that the Allies could
intercept and make use of signals so transmitted, that the aircraft had to be in the beam of the
Freya if it were to receive, and so an aircraft "lost" by the Freya owing to jamming could not be
communicated with and finally that, though intended for single-engined aircraft, fighter pilots
rarely had sufficient command of morse to be able to use this type of control.
Barbarossa
112. Barbarossa was a set designed to meet the same requirements as Barbara but to remedy
two of the drawback mentioned in the last paragraph.
113. The instructions to the aircraft were to be transmitted by code pulse modulations which
were passed through a "pulse filter" in the airborne set and a written indication obtained on a
Hellschreiber. The pulse filter and Hellschreiber unit were attachments to the FuGe 25A and
were known as the FuGe 139. This apparatus was in development at Rechlin under the
supervision of Stabs.Ing. von HAUTEVILLE.
114. With this arrangement pulse modulations could not be read by the Allies, and for spoof
purposes in order to produce a wrong indication we would have had to know the exact type of
modulation accepted by it. Visual indication was also quicker and did not depend on knowledge
of morse.
115. This scheme was only in a very early stage of development and P/W were unable to give
details. It was hoped that in due course it would be possible to develop matters a stage further
and find a means of transmitting scrambled speech instead of morse, but P/W understood that
the question of pulse modulation for speech transmission had not been solved.
Rübezahl
116. Consideration had been given in 1945 to the introduction of a crude system of navigation
which could be only used within the boundaries of the Reich. This was to go under the code
name of Rübezahl, and the fact that it was seriously considered and actively supported by the
P/W responsible for Navigational Aids on the G.A.F. signals staff is an interesting reflection of
the depths to which a combination of Allied jamming under-trained fighter had forced German
technique.
117. It was expected that in the course of the summer of 1945 thousands of 162 Volksjäger
would be available for the protection of the Fatherland. They were to be equipped with
FuGe 24, which was to become the standard G.A.F. R/T set as described in A.D.I.(K)
343/1945. This set did not for the present give Benito control facilities and indeed as they were
short-range, high speed, fair-weather aircraft it was not certain that Benito control would be
essentially needed.
118. It was essential that their relatively inexperienced pilots should have a simple means by
which they could locate their approximate position without any additional navigation
equipment having either to be manufactured or carried in the aircraft. It was therefore decided
to develop a system which could be used with FuGe 24.
119. In order to direct the Volksjäger pilots to their target, recourse was to be had to the night
fighter system of broadcasting a commentary, and this commentary was to be combined with
the primitive navigation system Rübezahl.
120. It was therefore planned to set up ground transmitters over Germany at 30 km intervals.
The transmitters were to be beamed upwards, so that at 6,000 meters the polar diagram was
about 40 km in diameter and lobes from neighbouring transmitters just overlapped, thus
covering the whole area. Each transmitter emitted a plain language recognition signal in the
form of the name of its district, e.g. Halle, Magdeburg, etc.
121. All transmitters were to be operated on the same frequency so that to locate himself the
pilot merely tuned his FuGe 24 to the frequency for the day. The ground transmitters were to be
adapted from the FuGe 15 transmitters which had been manufactured in quantity as described
in paras. 23-39 of A.D.I.(K) 343/1945 before it was found that the FuGe 15 was unsuitable as
an airborne R/T set. They were renamed Bs.15 (Bodensender).
122. Later it was believed that the night fighters which were also to carry FuGe 24 (see
appendix 1) would also use the Rübezahl commentary as yet another alternative source for
vectoring themselves to the bomber stream."