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Thread: RAF GROUPS assessed by German intelligence

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    Default RAF GROUPS assessed by German intelligence

    This shows the German knowledge of RAF Groups and advance indications of targets/routes. Early part is background, operational matters from item 9. These cover 2TAF, RAF and USAF routes and procedures.

    "SECRET A. D. I. (K) Report No. 406-45/1944
    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. SIGNALS INTELLIGENCE IN THE WAR - V
    Advance Warning, Route Tracking and Forecasting
    of offensives.
    1. In December 1939 a force of R.A.F. Wellingtons attempted a
    daylight attack on Wilhelmshaven. In the approach flight its
    radio traffic was picked up by German intercept units who, in
    contravention of their orders, immediately passed the results
    (location, height, course, etc.) direct to the higher
    authority concerned. As a result German fighters were directed
    to a favourable point for interception and, as is known,
    obtained some good results.
    2. After this success, the development of tactical evaluation
    (Sofortauswertungen) with direct landline links to the
    operational units was strongly advocated by the more
    enterprising young officers. There was strong opposition by
    superior officers on security grounds, but the progressives
    won.
    3. The outcome was that Meldeköpfe (reporting centres) were
    set up and were to be responsible for the collation and
    evaluation of intercepted and D/F signals and their
    distribution in standard form to the interested authorities.
    4. Meldekopf BIRK, set up on the Channel coast, was to
    supervise fighter operations, and Bomber-Meldekopf at Zeist in
    Holland for the special support of German night fighters. As
    the Allied Air Forces in the West became stronger, the
    activity of the Meldeköpfe became more important for both
    advance warning and route tracking. The advance warnings
    supplied by the Meldeköpfe were usually short-term, i.e. of
    hours or even minutes.
    5. Long-term forecasts of major Allied operations were
    provided by strategic evaluation (operative Auswertung). As
    the war progressed the evaluators gradually acquired so
    thorough a knowledge of Allied traffics, that they could often
    calculate enemy intentions from the minutest indications.
    6. The P/W who supplied the information contained in this
    report emphasises the fact that he did not work on either
    R.A.F. or VIII U.S. Bomber Command heavy bomber traffics, and
    therefore his knowledge is necessarily incomplete. The
    following were the sources of advanced warnings and routetracking
    data.
    ADVANCE WARNING AND ROUTE TRACKING.
    R.A.F. BOMBER COMMAND (APRIL) 1942 TO MARCH 1945).
    7. As long as P/W was with Referat B at Asnières there were
    always some means available for obtaining advance warning. As
    one source dried up, another was found. The following were the
    main sources from which the Signals Intelligence service drew
    their conclusions:
    (1) The traffic of every R.A.F. Bomber airfield was covered
    day and night. At certain fields definite indications of
    impending operations such as tuning-traffic or radio
    silence were observed.
    (2) The covering of R/T traffic on airfield frequencies (over
    5,000 kc/s) or on 6,440 kc/s disclosed such things as
    postponement of operations or very active take-off
    traffic.
    (3) From meteorological messages one could tell whether a
    particular airfield was fit for operations or not.
    (4) D/F Section tuning traffic.
    (5) Tuning traffic of Air-Sea Rescue boats before R.A.F.
    bombing ops. This was a certain indication for a long
    time, but was eventually dropped.
    (6) Interception and D/F'ing of I.F.F. This method was
    employed for a fair time with the R.A.F. and much longer
    with the U.S.A.A.F.
    (7) H2S and H2X interception.
    (8) Interception and D/F'ing of traffic from single aircraft,
    signalling that they would have to discontinue operations
    owing to engine trouble. S.O.S. calls, etc.
    (9) W/T orders from Group H.Q. to some or all of the units in
    the Group to break off operations. These orders were
    passed in the Bomber Code, most of which was broken.
    (10) Appearance of 100 Group's long-distance escort night
    fighters. Interception and D/F’ing of A.I. P/W stated that
    as the escorting fighters remained close to the bomber
    stream, the D/F’ing of the A.I. gave the position of the
    bomber stream.
    (11) Transmissions of the A.E.A.F. aircraft reporting centre in
    the vicinity of London, callsign Q28, known to the Germans
    as Freischuetz-Meldungen. This centre worked on several
    frequencies, both HF and LF, and transmitted blind for the
    benefit of all interested units, such as A.A. and night
    fighters, to warn them of impending operations by single
    aircraft or formations. These messages were passed in a
    3-letter code, which had been worked on for a considerable
    time, but was never broken. It was, however, inferred that
    the longer the message was, the greater would be the size
    of the raiding force and the longer the route. The longest
    messages were passed before major R.A.F. and Eighth Air
    Force raids. In the Paris area there was a similar radio
    station which repeated the messages when the track lay
    over French territory. Whenever station Q58 passed a long
    massage in the late afternoon which was re-transmitted by
    the Paris repeater,
    (a) There would be a major R.A.F.
    attack that night.
    (b) The R.A.F. formation would fly
    over France.
    If an operation had to be cancelled on account of
    deteriorating meteorological conditions, a message was
    transmitted saying "Cancel my message No....." which was
    passed at once by the German Signals Intelligence service
    to the competent quarters.
    (12) Transmissions of an American aircraft reporting centre in
    France (presumed to belong to the IXth Air Defence
    Command: German cover-name:- Wildkatzen messages). The
    structure of these messages had been broken since the
    African campaign, e.g.
    T67 PS M8013 W1 H A8
    Explanations:- T67 - Target number 67.
    PS - Re-cyphered track.
    M8013 - Location. Re-cyphered
    modified system (broken).
    W1 - No. of aircraft.
    H - Hostile (F = friendly,
    X = unidentified).
    A8 - Height in angels.
    This kind of traffic appeared from the beginning of the
    invasion, but brought mediocre results, as movements of
    German aircraft were mainly reported, and very soon it
    dropped altogether, presumably because landlines were set
    up.
    From about autumn 1944 an American station regularly
    reported Allied formations as well as German ones, thus
    providing a new and very reliable source of early
    warning. Most of the first positions lay in the Amiens -
    Abbeville area, the last ones roughly at the German
    border.
    (13)Interception and D/F'ing of 100 Group airborne jammers.
    The jammers were positioned over the North Sea or over
    Belgian or Dutch territory and sometimes flew with the
    bomber stream into Germany. The appearances of the
    jammers was no sure indication of impending operations,
    but it was certain that if no "mandrel" screen appeared
    there would be no major raid.
    (14) Interception and D/F'ing of W/T and R/T traffic during an
    operation. In the case of the R.A.F. this was almost nonexistent,
    but when it did occur, as for example on 6,440
    kc/s by the Master of Ceremonies and on V.H.F. by the
    Master-bombers of 5, 8 and 100 Groups, it was eagerly
    seized upon.
    (15) Interception of J-Beams (called Rodelbahn by the Germans).
    The determination of the beam direction was made
    difficult by the concentration of the beams. Naturally it
    was most favourable when the beams happened to pass over
    an observation station. With increasing distance the beam
    breadth increased to such an extent that only the
    approximate area of attack could be established, to for
    example, North Germany or South Germany. An attempt was
    made towards the end of the war to-determine the
    exact bearing of the beams by means of special
    observation aircraft. Results were negligible.
    8. The results of observations from all outstations were
    collated at the Meldeköpfe and if an operation was indicated,
    the control officer (Leitoffizier) released the cover-word
    "Adler"; if no operation was indicated "Taube".
    COMMENTS ON R.A.F. BOMBER GROUPS.
    5 Group.
    9. 5 Group was known to hold a special position in Bomber
    Command; it had small specialist formations which carried out
    daylight attacks on special targets such as dams, port
    installations and ships (Tirpitz), etc. At night it operated
    mostly separately from the other bomber groups. By
    extraordinarily good discipline in the use of radio and
    navigational equipment, it caused the G.A.F. signals
    intelligence the maximum amount of worry, as in the case of
    one attack on Munich which took place at 0500 hours. On that
    occasion the first radar intercepts were made when the
    formations were almost over Munich and as the ordinary
    aircraft reporting service had failed, Munich was taken
    completely by surprise, without even an air raid warning being
    given.
    3 Group.
    10. The daylight attacks, carried out chiefly by No. 3 Group
    provided very little early warning. Often the Lancasters were
    over the German frontier before the warning was given. In many
    cases the R/T traffic of Fighter Command escorts gave the
    first indication of daylight attacks.
    11. The special agent- supplying operations of the Tompsford
    Squadron (138 and 161) were never intercepted before or during
    an operation, but at best on the return flight. Many attempts
    were made to forecast the dropping area or subsequently to
    locate them by calculation, but neither the listening service
    nor the radar observation service produced any useful results.
    8 Group.
    12. The radio discipline of this Group was also above the
    average. Often it could only be gathered that 8 Group aircraft
    were taking part in a raid from the Group H.Q.'s
    meteorological transmissions.
    13. On the other head, the Mosquitoes which regularly attacked
    Berlin towards the end of the war were always picket up in the
    area of the Frisians by means of H2S interception and D/F.
    8th AIR FORCE EARLY WARNING AND ROUTE TRACKING
    14. The raid forecasts of R.A.F. Bomber Command produced by
    the Signals Intelligence service were fairly reliable, but
    sometimes complete surprises and wrong decisions did occur. On
    the other hand, P/W stated that it could safely be said that
    no 8th Air Force raid ever came as a surprise. Advance warning
    of some hours was generally given, and the sources were as
    follows:-
    (1) Preparations for a raid indicated by airfield W/T and R/T
    activity.
    (2) Switching-on of Splasher beacons to assist assembly.
    These beacons were frequently switched on when no raid was
    projected, but on the other hand no raid took place
    without the assistance of the beacons. From the locations
    of the beacons switched on rough estimates could be made
    of the direction of the attacks. If the beacons in S.W.
    England were transmitting, the attack could be expected in
    the direction of France and Belgium; if those in N.E.
    England were working, then the target would lie in the
    Heligoland Bight - Norway direction.
    (3) Meteorological reconnaissance in the assembly area. To
    determine the best height for assembly, meteorological
    reconnaissance aircraft took off before a projected raid.
    The appearance of these aircraft showed the intention to
    carry out a raid.
    (4) Radio traffic during assembly. If the meteorological
    reconnaissance reported favourable conditions, the bombers
    started to assemble. The assembly took place over the Wash
    and was so difficult that air-to-air R/T traffic became
    essential. Upon observation of this traffic, which could
    be intercepted even in Germany itself, the cover word
    "Zugvoegel" was released (i.e. U.S.A.A.F. major operation
    expected). Even during assembly the exact composition of
    the force (Divisions, Combat Wings, etc.) and their
    position in the formation could be ascertained from the
    frequencies employed.
    (5) Take-off of fighter escort. The assembly took place
    without fighter protection and the fighters took off when
    the assembly was completed. Thus the first appearance of
    fighter R/T indicated that the assembly was complete and
    the force had already started out.
    (6) Control Point Messages. When the formations passed certain
    control points the formation leaders had to send a W/T
    message encoded in Bomber Code to their H.Qs. According to
    the length of the formation, and as all the messages could
    not be received simultaneously by the ground station, it
    was possible by D/F'ing this W/T traffic to make a rough
    estimate of the track.
    (7) Open transmitters. It often happened that V.H.F. R/T sets
    TR.5043 or H2X were left switched on. A D/F on the carrier
    frequency obtained a good track.
    (8) Air-to-Air R/T traffic (Bomber-fighter, fighter-fighter).
    This very active R/T traffic was, of course, thoroughly
    monitored. A study of their contents yielded the following
    results:-
    (a) Heights and speeds.
    (b) Locations (We are over Cologne).
    (c) Indications of effectiveness of
    G.A.F. Fighter and Flak defences.
    (d) Deviations from the original plan.
    (e) Preparations and order to release
    bombs.
    (9) W/T traffic during an attack. Messages from aircraft to
    ground station and vice-versa were usually sent in the
    Bomber code, which was regularly broken. They contained
    the following information:-
    (a) H.Q. orders to break off operations.
    (b) Alterations in the original plan (e.g.
    changing of the rendezvous point of bombers
    and fighters).
    (c) Bombing results, stating whether primary
    or secondary targets attacked;
    whether visual or radar bombing used
    and with what effect.
    (d) Damage reports from single aircraft.
    (10) D/F of navigational transmissions. H2X and GH were the
    most useful in this respect.
    (11) Up to the time when the escorting fighters became capable
    of accompanying the bomber stream over the entire route,
    each relieving formation of fighters had to fly directly
    to the rendezvous point with the bombers, thus indicating
    the direction of the target area. This was much more
    reliable than a D/F on the bomber formation, which
    regularly flew on "spoof" routes.
    MEDIUM BOMBER FORMATIONS.
    2nd Bomber Group, 2nd T.A.F.
    15. There were no possibilities for obtaining early warning
    from 2nd Bomber Group as their radio discipline was very good.
    Observation produced only insignificant results.
    IX Bomber Command (or 9th Bombardment Division).
    16. Approaching formations were often followed by D/F’ing the
    V.H.F. W/T traffic. As their W/T security was good, however,
    not much success was obtained.
    17. When, in December 1944, the medium bomber formations of
    IX Bomber Command went over to bad-weather attacks under Oboe
    control new sources of early warning came into existence. The
    Oboe control stations were by then in the Belgium – France
    area, and the monitoring of these W/T stations both before and
    during operations provided the means of forecasting an attack
    as much as 45 minutes ahead, and the actual targets 8 - 25
    minutes ahead. The ground-to-air V.H.F. control traffic
    produced no such result.
    18. The control station of the various radio networks lay in
    the U.K. and had the callsign X25. The evaluation was done
    without cryptographic breaking. With the exception of IX
    Bomber Command attacks, the same method applied to the Oboecontrolled
    attacks of 8th Group in so far as the control of
    the W/T stations was carried out on the Continent and not in
    the U.K.
    42 Bomber Wing/Brigade Tyrol (1st U.S.T.A.F.)
    19. Early warnings of the approach of 42 Wing forces were
    deduced on the basis of D/F's on the R/T traffic of
    approaching bomber formations. The R/T security was not as good
    as that of the tactical bomber forces in N.W. Europe, and
    route-tracking was therefore relatively easy.
    FORECASTING OF OFFENSIVES
    THE INVASION.
    Formation of the A.E.A.F.
    20. Since its setting up in May 1943, 2nd T.A.F. used
    different callsigns from those of the rest of the R.A.F.;
    these consisted of a letter followed by figures. When the
    A.E.A.F. was set up in January 1944 the 9th Air Force adopted
    the 2nd T.A.F.'s callsign system. This showed that unity of
    command of the short range bomber forces had been achieved,
    which new authority was referred to in press reports as the
    A.E.A.F. From that moment A.E.A.F. stations were easily
    distinguished from all others.
    The Conclusion of Training.
    21. In March 1944 a huge Allied exercise (cover-name Spartan),
    in which Army and Air Forces took part, was hold in S.E.
    England. After this, apart from a few minor radio exercises,
    there was no more of this kind of activity. The obvious
    conclusion was that the period of training was at an end and
    preparation for the real thing was under way.
    Change of Location of T.A.F. Formations.
    22. The radio networks of 2nd T.A.F. had been virtually solved
    by signals intelligence since 1943. In the spring of 1944 all
    the radio stations of 83 and 84 fighter groups had been
    regularly D/F'd, as it was considered that the movement of
    these units would provide indications of the coming invasion.
    All chances of location were evaluated immediately: in April
    and May 1944 almost all the radio stations of 83 end 84
    fighter groups moved into the Portsmouth area (Tangmere) and
    those of the 2nd bomber group to the Reading - Odiham area.
    The focal point of the fighter formations lay clearly around
    Portsmouth.
    23. The intelligence thus obtained from the monitoring of W/T
    ground stations, was fully confirmed by V.H.F. R/T traffic.
    When the Headquarters of 83 and 84 Groups moved to the South
    coast in May 1944, the indication of the end of the Allied
    preparations and the direction of the planned attack was
    unmistakable.
    IX end XIX Tactical Air Commands.
    24. Up to the spring of 1944 the monitoring of the 9th U.S.
    Air Force had produced the following results:-
    (a)The fighter formations of the 9th Air Force were
    subordinated to the IX Fighter Command and
    were attached to the 8th Air Force. They were
    stationed in the Wash area and escorted 8th
    Air Force heavy bombers in the same way as the
    VIII Fighter Command.
    According to all available intelligence there
    was only one fighter Wing of the 9th Air Force
    ready for operations. Some detailed prisoners
    at Dulag Luft had stated that it was called 70
    Wing, but others had said it was 100 Wing. As
    the 9th Air Force was to support an Army Group
    in the invasion, the fighter units temporarily
    operating with 8th Air Force would have to be
    re-subordinated to the 9th Air Three. Thus
    signals intelligence concluded that as long as
    the 9th Air Force fighters continued to
    operate with the 8th Air Force there would be
    no invasion.
    (b)There were two Air Support Commands (IX and XIX)
    each one of which was to support an army. The
    IX A.S.C. was probably taken over from the 8th
    Air Force, and the XIX newly formed. Both
    formations were known from many plain language
    messages transmitted during exercises. These
    Air Support Commands were later re-named
    "Tactical Air Commands". At first 2nd T.A.F.
    only had Air Support Parties and a Tactical
    Reconnaissance Group each (IX TAC had 67
    Tactical Reconnaissance Group and XIX TAC had
    10 Tactical Reconnaissance Group) at their
    disposal.
    25. In order to carry out their function of supporting an army
    each, the Tactical Air Commands would have to be brought up to
    operational strength sooner or later. In the middle of May
    1944 the expected development took place, being indicated as
    follows:-
    (i) In the 9th Air Force ground networks great
    changes occurred, which could not be
    completely elucidated as there was a reallocation
    of callsigns. This, however,
    constituted an initial warning.
    (ii) The fighter formations of 70 (100 ?) Wing
    ceased to be subordinated to 8th Air Force,
    were moved to the Maidstone area and started
    using 9th Air Force frequencies.
    (iii) Suddenly some new U.S. fighter formations
    appeared simultaneously on a large number of
    frequencies, which could be divided into two
    major groups. Firstly, a large formation of
    about eleven Groups lay in the area of Middle
    Wallop and South of it, and secondly, a
    smaller formation of about nine Groups,
    amongst which was 70 (100 ?) Wing was located
    in S.E. England (Maidstone). It was thus
    clear that the expected bringing up to
    strength had taken place, but it could not
    yet be determined which was the IX and which
    the XIX Tactical Air Command.
    Preparations by IX Troop Carrier Command.
    26. The following facts were already known:-
    (a)In the control network of the 9th Air force a
    new station, D/F'd in the Grantham -
    Cottesmore area appeared. This station was
    simultaneously identified as the control
    station of three subsidiary networks, D/f'd in
    the Exeter, Aldermaston and Grantham -
    Cottesmore areas.
    (b)Monitoring of air-to-air W/T traffic produced
    numerous new U.S. aircraft callsigns. It was
    at first believed that a new bombardment
    Division of 8th Air Force was being set up,
    but it was soon clear that it concerned twinengined
    aircraft which were used chiefly for
    transport purposes. Many shuttle flights were
    observed in the Grantham - Cottesmore area.
    From a statistical consideration of these
    flights and study of the callsigns, the
    strength of this formation was estimated at
    about 1,000 aircraft.
    (c)The above aircraft used the Bomber Code. Many of
    the messages were broken and showed that the
    aircraft were almost exclusively C.47
    (Dakotas). In another Bomber Code message 50
    Wing was mentioned. 51 Wing had been known in
    Italy as a transport Wing, and so it could be
    safely assumed that transport aircraft were in
    question.
    (d)From the Monitoring of H.F. R/T traffic of
    Fulbeck airfield (near Cottesmore) on about
    5,100 kc/s, it was ascertained from messages
    like the following that great training
    activity with C.47's and freight gliders was
    in progress:-
    "Have you the glider in tow?"
    "There is a 9-ship formation of
    C.47's with gliders in tow.
    "Can you see the match-box?"
    Gradually it became obvious that a fairly
    large force of C.47's, suitable for towing
    gliders and transporting parachute troops, was
    subordinated to the 9th Air Force. There were
    indications that the formation was IX
    Transport Command, but its correct designation
    appeared soon afterwards to be IX Troop
    Carrier Command. Thus, large-scale use of
    airborne forces could be expected at the
    beginning of the invasion.
    Preparations by R.A.F. 38 Transport Group.
    27. The ground network of 38 Wing (later Group) when it was
    subordinated to Army Co-operation Command had been analysed
    since 1942. Occasionally ground-air traffic messages in Bomber
    Code were de-coded, showing that 38 Group too was being
    prepared for airborne operations. On the whole, however, the
    depth of traffic was less than that of IX Troop Carrier
    Command. Traffic links between 2nd T.A.F. and Netheravon (H.Q.
    of 38 Group) indicated close liaison between both formations.
    Control Stations on Warships.
    28. At the end of May 1944 it was established that American
    flying control stations on board warships were once more
    providing the units ashore (e.g. A.S.P.'s) with the means of
    communication. D/F's indicated Plymouth and Portsmouth. Thus
    it was clear that embarkation for the invasion had begun.
    29. At the end of May the G.A.F. Signals Intelligence service
    issued a pre-invasion warning, approximately in the following
    form:—
    "All the preparations of the British and American
    Air Forces are completed. Two American and two
    British short—range bombing forces are ready on the
    south coast of England to support four armies.
    The embarkation of staffs has begun. A major
    landing is to be expected any day now."
    30. The landing itself was picked up as follows on the night
    of 6th June 1944.
    (1) Shortly before midnight very strong jamming activity,
    attributed to R.A.F. 100 Group was directed against German
    ground radar. The jamming screen moved slowly from East to
    West, so that it was at once assumed that its purpose was
    to screen a fairly large formation of Allied vessels.
    (2) The weather reconnaissance and the assembly of American
    bomber formations of VIII and IX Bomber Commands began
    long before the normal time. This striking advancement of
    take—off times similarly showed that something special was
    afoot.
    (3) The approach of the landing fleet was achieved with
    complete radio silence. The traffic which was transmitted
    immediately on landing was intercepted and evaluated
    according to the pre-arranged formulas.
    FORECASTING OF ALLIED OFFENSIVES.
    General.
    31. After the invasion it was rapidly established that certain
    air formations always supported certain army formations,
    thus:—
    83 Fighter Group - 2nd British Army.
    84 Fighter Group - 1st Canadian Army.
    IX T.A.C. - 1st U.S. Army.
    XIX T.A.C. - 3rd U.S. Army.
    XXIX T.A.C. - 9th U.S. Army.
    XII T.A.C. - 7th U.S. Army.
    32. From movements, increases in strength and other changes of
    the air force formations, conclusions could be drawn
    concerning the related army formations. The monitoring of
    tentacle and A.S.P. traffic produced intelligence on the Army
    Order of Battle. This task was facilitated by the A.E.A.F.'s
    use of fixed callsigns. From May 1944 till the end of the war,
    there was no change of callsigns.
    First Operation of the 9th U.S. Army in November 1944.
    33. The impending employment of a new Tactical Air Command and
    consequently of a new U.S. army became known in the following
    manner:-
    (i) In the control network of the 9th Air Force a new
    station appeared which was also the control station
    of a subsidiary network. In this new network only
    callsigns of fighter croups, which were formerly
    subordinated to IX or XIX T.A.C., appeared. Thus, it
    was concluded, a new Tactical Air Command must have
    been created.
    (ii) In a broken M209 message, XXIX T.A.C. was mentioned.
    (iii) Monitoring of V.H.F. R/T showed the same development.
    The appearance of a new callsign (Rosalio) and of
    the fighter croups formerly subordinated to IX and
    XIX Tactical Air commands. D/F's on the headquarters
    of IX and XXIX T.A.C. and on the subordinated Groups
    indicated a powerful concentration of Allied forces
    West and North-West of Aachen.
    34. At the same time certain A.S.P.'s were dropped from the
    3rd and 7th Army sectors and appeared in the 1st or 9th army
    sectors with the same callsigns. This was a clear indication
    of the change of location of the corresponding ground forces.
    On the basis of this intelligence it could be announced that
    two U.S. Army was ready to open a major attack in the Aachen
    area, and that the newly identified 9th Army would take part
    in it.
    The Final Allied Offensive in the West (February — March 1945).
    35. The German Ardennes offensive in December 1944 had
    produced considerable re-grouping Of Allied forces. In the
    first stage of this German offensive certain Groups from all
    of the Tactical Air Commands are subordinated to IX T.A.C. At
    the beginning of the 3rd Army's counter—offensive the XIX
    T.A.C. had eight Groups allocated to it, while at the same
    time XXIX T.A.C. was almost completely stripped keeping only
    two Groups. The 8th Air Force sent two fighter groups from the
    U.K. to Franco to strengthen the 9th Air Force. After the
    repulsing of the German offensive, the following facts
    indicated preparations for a new Allied offensive:—
    (i) The XII T.A.C. was strengthened by two Groups, taken
    from the XXII T.A.C. in Italy, but had to give one
    Group to XIX T.A.C.
    (ii) IX, XIX and XXIX T.A.C.'s each had five fighterbomber
    and one tactical reconnaissance group
    allocated to them. Thus all the American armies had
    air support of equal strength. It appeared from the
    shorter combat fronts of the 1st and 9th Armies that
    the focal point of the attack would clearly lie on
    the American northern wing, roughly in the area of
    Aachen.
    (iii) The formations and headquarters of 84 fighter Group
    moved North—East, immediately behind the front.
    (iv) All British and Canadian tentacles were subordinated
    to the 1st Canadian Army. From (iii) and (iv) the
    inference was obvious that the Canadians would make
    the initial thrust.
    (v) Shortly before the offensive the advanced
    headquarters of 9th Air Force was D/F'd at Namur to
    which it had moved from Luxemburg, emphasising the
    fact that the main centre of attack would be on the
    U.S. northern wing.
    (vi) The advanced headquarters of A.E.A.F. had been D/F'd
    in Rheims. The re-appearance of this advanced
    headquarters was a clear sign that an attack was
    imminent.
    FORECASTING OF GROUND OPERATIONS ON THE BASIS OP AIR SUPPORT
    RADIO TRAFFIC.
    W/T Traffic.
    36. As explained in Part IV of this series (A.D.I.(K)405/1945)
    the Army-Air exercise traffic and the exercises which took
    place in the U.K. between Dieppe and D-Day offered great scope
    for calculating intentions. As a result of this study the
    following preparations were made to deal with invasion, when
    it should be launched:-
    (i) Meldekopf II was set up in the Paris area with the
    task of evaluating Allied air traffic, especially
    that of the A.E.A.F.
    (ii) All interested Army and G.A.F. stations received the
    special key (Senderschluessel) to enable them to read
    the W/T warning transmission (Warnfunk) of Meldekopf
    II.
    (iii) All outstations were provided with all the necessary
    documents to enable them to take over another
    station's functions, should it cease to operate.
    37. Immediately after the landing on 6th Jude 1944 the
    expected forms of traffic were picked up. These were chiefly
    requests for air support from the British tentacles and the
    American Air Support Parties and took the following form:-
    Tentacles: A) Guns in V2012 (description of target).
    B) Bombers (desired type).
    C) 1120 (time of operation).
    D) Not S. of
    river
    (special instructions).
    E) Light A.A. (type of defence expected).
    F) 0920 (T.O.C.).
    A.S.P.’s.
    38. The German intercept operators were instructed to call
    their N.C.O. in charge of the shift as soon an A.S.P. message
    began to come through. A typical message would read as
    follows:-
    A) PLK/4. (Callsign and request signal number).
    B) Enemy tanks at V 8013.
    C) ASP (As soon as possible).
    D, E, F) Similar to above.
    39. As soon as A, B and C were picked up the message was
    passed on for further action and in this way valuable minutes
    were saved. In many cases it was reported that the message had
    been delivered in time for countermeasures to be taken. These
    massages were sent later in the Slidex Code, but the breakers
    worked rapidly enough to prevent any serious delay.
    40. Warnings were also provided by the W/T networks which
    transmitted the results of short-range reconnaissance, and the
    Army 'Tactical reconnaissance broadcasts' were also useful in
    providing the following intelligence:-
    (i) Focal points of reconnaissance. Each message was
    flagged on a map. In this way conclusions as to
    intentions could be drawn from flag concentrations,
    etc.
    (ii) Railway activity, positions and movement of troops,
    etc. Co-operation with the railways was especially
    close. They received all the messages concerning
    them and took steps accordingly.
    R/T Traffic.
    41. After the break-through at Avranches the Americans began
    to carry out almost their entire air support traffic by
    V.H.F. R/T. The control of fighters virtually passed from the
    H.Qs. to the A.S.P.'s which operated with the armoured
    spearheads and at other vital points. As a result of their air
    superiority the Americans could afford to keep a constant air
    umbrella over the points of attack, which could be called off
    in case of need by the A.S.P.'s and switched on to other
    profitable targets.
    42. The warning activities of Meldekopf II were interrupted
    for a time on account of the above-mentioned changes of
    tactics and frequent changes of location. But experimental,
    squads, working near the front line, soon found new means of
    obtaining signals intelligence, and these were put into use by
    September 1944 when the western front became more stable.
    43. It was found that the time lapse between the briefing by
    A.S.P.'s and the actual attack was too short to live adequate
    warning to the threatened formations with the method which had
    been successful for the former W/T intercepts. The former
    routine was:-
    (i) Interception by intercept stations.
    (ii) By landline or radio to Meldekopf.
    (iii) Decoding.
    (iv) Broadcast on W/T warning transmitter.
    (v) Pick-up by divisions, etc.
    (vi) Decoding.
    (vii) Passed to threatened formation.
    44. Even under the most favourable conditions there was a
    time-lag of 15-20 minutes, so intercept squads of three to ten
    men with one to three receivers were set up at Army Group,
    Army, Army Corps and sometimes divisional H.Q.'s, solely to
    deal with the immediate evaluation of A.S.P. R/T traffic.
    These squads only monitored the V.H.F. R/T traffic of the
    T.A.C. in their own sector, and proved their worth in the
    American sectors of the Western front. Attempts to do the same
    thing in the British sectors produced little result, for the
    British tentacles continued to use W/T. The R/T traffic of 83
    and 84 Groups had for some time not given so many
    opportunities for advance warning as the Tactical Air Command.
    45. The present P/W was officer in command of an R/T squad
    with Panzer AOK 5 in the winter of 1944-1945 and for a time
    with 11th Panzer Division, first in Alsace-Lorraine and then
    in the Düren sector. These are a few examples of traffic
    passed about this time:-
    Callsign Key:
    Ripsaw ...... H.Q. XIX T.A.C.
    Limber ...... A.S.P. with 2nd French Armoured
    Division.
    Eggcup ...... A.S.P. with 4th U.S. Armoured
    Division.
    Vibrate...... Squadron callsign.
    Rabbi ....... Squadron callsign Tactical
    Reconnaissance Squadron.
    Vibrate leader calling Ripsaw .... We are airborne
    now. Ripsaw .... Go to Eggcup. He has a target for
    you. Vibrate calling Eggcup .... Have you a target
    for me. Eggcup .... Yes. There is a very important
    C.P. at Q.3859. Repeat Q 3859.
    Vibrate .... I understand C.P. at Q 3859.
    Result.
    Immediate warning to the threatened C.P. There were
    eleven minutes (and often more) before the attack
    could be launched, as the Squadron had to locate the
    target first. In this time personnel and key
    equipment could be moved to safety.
    Example 2:
    The 2nd French Armoured Division got into
    difficulties as the result of a German counter
    attack. The A.S.P. appealed to all available air
    forces for help: "Limber calling trouble". The
    enemy's weakness as indicated by this message was
    fully exploited by our own Command.
    Example 3:
    The Vibrate squadron was frequently referred to
    Eggcup on a late afternoon sortie.
    Eggcup .... There are about ten enemy tanks in
    the village at V 7853.
    Vibrate Leader .... We are in the target area,
    but we cannot see anything.
    It's too late for today.
    Eggcup .... O.K. Return to base. We shall attack
    these targets tomorrow morning.
    Result:
    Early warning to the panzers concerned, who
    changed their location and camouflage.
    46. Of course not all the warnings arrived in time, but the
    warning squads (Horch Verbindungskommandos: H.V.K.'s) won a
    great reputation on the strength of their timely warnings.
    These were in a position to provide their army formations with
    an accurate current air situation picture, which was most
    important for the employment of reserves and transport, e.g.:
    0900: In our own sector still absolute quiet. Net.
    recce aircraft report bad visibility.
    1040: One fighter squadron taken off. Flying into the
    Metz sector to attack gun sites.
    1050: Three more fighter bomber squadrons taken off.
    Danger of fighter bomber attacks for the whole
    sector. Centre of attack probably Metz.
    1135: Fighter Bombers break off operations owing to
    weather conditions.
    1230: Further enemy air activity at present unlikely
    owing to weather conditions.
    1500: Further low fog over enemy airfields. In spite
    of fine weather in our own sector no fighterbomber
    activity expected.
    47. The H.V.K.'s also monitored pure army traffic (V.H.F. R/T
    20 - 40 mc/s.), e.g. artillery spotters and observers, tanks,
    etc. The Army was considerably behind in the matter of R/T
    monitoring and was often surprised at the results of the
    squads.
    48. The A.S.P.'s used fixed callsigns from May 1944 to March
    1945 and each A.S.P. was attached to a particular Division or
    Corps. The A.S.P. of the 30th Infantry Division, for example,
    kept the callsign "Ironclad", that of the 4th Armoured
    Division "Eggcup". The A.S.P.'s always transmitted on the
    frequency of the T.A.C. of their respective Armies. Thus the
    monitoring of A.S.P. traffic produced the following results:-
    (a) Which divisions were being employed.
    (b) Which army they were subordinated to.
    (c) The exact sectors in which they operated.
    49. When, in March 1945, a system of frequently changing
    A.S.P. callsigns was introduced, this source of strategic
    intelligence was no longer available.
    Forecasting of Airborne Landings.
    50. The G.A.F. Signals intelligence service had least success
    in forecasting airborne operations. Neither the major landing
    in Normandy in June 1944, nor that in Arnhem-Eindhoven, nor
    yet the great supply-dropping operation for the American
    troops surrounded in Bastogne, were picked up. The
    preparations of the IX Troop Carrier Command and of R.A.F. 38
    Group were known, but no tactical indication of the actual
    operations was given. There were two reasons for this
    failure:-
    (i) The excellent radio security of the transport units
    during these operations.
    (ii) The failure of the intercept Kompanien of the German
    Intelligence service.
    51. After the withdrawal from France a new organisation was
    set up to monitor air transport traffic. This monitoring was
    transferred from III/Ln. Regt. West (later Ln. Funkaufkl. 357)
    to a newly created Kompanie of Ln. Funkhorch Abt. West (later
    called Ln. Funkaufkl. Regt. 351). This reorganisation was
    being carried out when the airborne landing over Eindhoven-
    Arnheim took place; thus the repulsing of the British airborne
    landing at Arnheim was not due to G.A.F. signals intelligence
    work. This new Kompanie, which employed many females, produced
    better results for long-term intelligence, but failed to pick
    up the supply-dropping operation over Bastogne. This brought
    the Signals intelligence service no small amount of criticism
    from the commands.
    52. The Signals Intelligence service was able to give about an
    hour's advance warning of the Bocholt operation in March 1944
    and to give a running commentary on the approaching formation.
    But even in this case the intelligence came, not from
    monitoring of radio traffic, but from the American aircraft
    reporting service (Wildkatzen messages); yet the preparation
    of American transport formations had again been correctly
    recognised. Only the place and exact time of the operation had
    not been established, but the concentration areas of
    reconnaissance flights and other indications described earlier
    in this report provided sufficient evidence to make a fairly
    reliable forecast as follows:-
    (i) By the changes of location of 52 and 53 Wings of IX
    T.C.C. from the U.K. to France, where 50 Wing had
    already been for some time. These movements were
    accompanied by numerous P/L messages, from which all
    the details of the operation could be followed.
    (ii) Radio silence or considerable limitation of traffic
    from the H.Q. transmitters of 52 etc. Wings, as well
    as other traffic indications.
    (iii) It had not been clear for some time where the
    82nd and 101st (American) Airborne Divisions were
    located, but it was known from radio intelligence
    that they had been pulled out of the western front.
    Then a few police (presumably movement control or
    M.P.) messages provided the answer. The contents
    were roughly as follows:-
    "Tomorrow from 0900 to 1100 hours the road from
    ...... to Mourmelon will be kept free from
    traffic, as the (either 82nd or 101st) Airborne
    Division is moving from ...... to Mourmelon with
    vehicles."
    (iv) Photographic reconnaissance then investigated the
    Mourmelon (near Reims) camp and the pictures showed
    about 1700 ten men tents and a proportional number
    of Dakotas.
    (v) In a similar way the location of the other airborne
    division was established.
    (vi) 38 Group had moved from the area of Metheravon to the
    N.W. of London, with H.Q. at Earls Colne, suggesting
    that this group would again be employed.

    A.D.I.(K) and S.D. Felkin
    U.S. Air Force Intelligence. Group Captain
    30th October 1945"

    Bruce
    http://www.filephotoservice.co.uk/
    RESEARCH AT THE NATIONAL ARCHIVES & OTHER UK INSTITUTIONS

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    Wow! Thanks Bruce. Fascinating stuff.

    Amazing what they were able to work out.

    Ian

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