German code breaking during WW2, Part Five

well_chuffed, Going Postal
92d Bombardment Group senior Pilots pose in front of Boeing B-17F 42-30455 at RAF Alconbury, England, after a successful mission to Hülser Berg Germany in late June 1943. Equipped with radar, this aircraft flew several missions as the lead aircraft of the group

The following is a description of the course of a typical American heavy bomber raid and , as in the case of the example of an RAF raid , represents tactics during the latter years of the war. Research work , as was also the case with the RAF , was really not necessary ; the Americans spoke of whatever they were doing quite openly at times.

23:00 Since R/T and W/T traffic is being sent from 8th USAAF airfields , a raid must be intended for the next day.

03:30 A weather reconnaissance aircraft from Molesworth sends a message. A fix cannot be obtained from this one message.

04:30 Now weather ships of the 2nd and 3rd Bomber Divisions send messages ; they are plotted over the assembly area in England.

05:15 A light jamming screen appears over the southern portion of the North Sea and off the eastern coast of England. At the same time the first take-off messages are intercepted on W/T frequencies. The first operational call-signs are sent on the airfield W/T frequencies , an indication that this is no training flight , but rather a raid is taking place.

05:20 A second weather reconnaissance aircraft of the 3rd Bomber Division is plotted while sending a message from a position over France. Inference : the 3rd Bomber Division , at least in part , will assemble over the continent (their assembly areas are learned from D/Fing the radio beacons , as well as from captured documents).

06:00 Although it is known from the preceding W/T traffic , as well as from HF R/T messages , that the assembly is taking place , it is curious that still no VHF traffic is heard.

06:20 Individual aircraft are heard in tuning traffic with their ground stations (these tuning messages are especially frequent in the case of the 2nd and 3rd Bomber Divisions). Bearings indicate that they are heading for the continent. A few formation leaders of the 2nd Bomber Division are now heard on VHF R/T , still over the assembly area in England , approximately over Cromer. With the exception of the reconnaissance aircraft , there is still no sign of the 1st Bomber Division (the 1st Bomber Division , especially in the last period of the war , exercised exemplary restraint in its use of radio). A picture of the situation is now passed on to the people concerned : the 2nd and 3rd Bomber Divisions are assembling over the continent in considerable strength ; of the 1st Bomber Division , which will also probably take part in this operation , nothing can yet be said as to when and where it will assemble.

07:00 A jamming screen is reported over the Belgium-Holland border area. It is not a reliable indicator of a four engined raid ; it can just as well be a screen for a Marauder attack. At the same time the first VHF traffic from the assembly area over France is intercepted. Call signs of formation leaders and squadron colours are learned. The ZAF is given a preliminary picture of the expected strength while the division is still assembling. During the assembly , answers to questions concerning the stage of assembly are being given interested headquarters ; at the same time , the signal intelligence picture is being completed by calls to the SIS out-stations.

07:30 All the combat wings have now been D/F’d ; while up to now , orders have been given principally on the wing frequencies , now the messages are sent on the division frequency. Therefore the assembly is nearing its final stage. Meanwhile the 1st Bomber Division has been heard in its assembly area over France , so that a comprehensive picture of the air situation can now be given ; only the stage of assembly in the case of the 1st Bomber Division is still not known.

07:40 the first R/T traffic on the frequency of the fighter escort is heard ; the approach flight must begin in the next few minutes.

07:45 The first message during the flight to the target is intercepted. It reads as follows : on time minus eight , on course , visibility three , TOO (time of origin) 07:40. At this point the defence is alerted. By D/Fing these obligatory messages the exact position of the formation is learned. In the case of the 3rd Bomber Division , each combat wing commander has to send one of these messages , thus the Luftwaffe SIS can determine the strength of this division. Generally its strength can be reported quite accurately to German tactical headquarters during the flight from the assembly area. Early in 1944 , some unit commanders of the 1st and 3rd Bomber Divisions even availed themselves of the MF D/F network in order to orient themselves while still over the sea on their outward flight. It was quite obvious that practically nothing was being done to conceal the intentions of an attack.
Henceforth , continuous tracking is guaranteed by D/Fing the abundant R/T and W/T traffic. A third prolific source of bearing is the “Mickey” equipment.

08:00 The first weather ships , reconnoitering the outward flight course , are heard on R/T and appropriate D/F stations are detailed to monitor them continuously. By following them the route of the bombers can be accurately predicted. There were days on which weather reconnaissance aircraft could be plotted enroute to the target , two hours before the bomber formations left the assembly area. In the last period there was an increase in the number of cases where their messages were not sent through relaying aircraft on VHF , but on W/T. Special mention should be made of those weather ships of the 15th USAAF which revealed targets to the Luftwaffe SIS many hours before the raids actually began.

well_chuffed, Going Postal
B-17 Flying Fortresses from the 398th Bombardment Group fly a bombing run to Neumünster, Germany, on 13 April 1945

09:00 The first German fighters are mentioned in the bomber R/T traffic. Large scale aerial battles were not frequently revealed in the signal intelligence picture ; only in the case of several heavy raids on Berlin was there a plethora of reports of attacks , of comments on the aggressiveness of the German fighters , of curses from the unit commanders and reprimands to their disorganised formations. The signal intelligence picture was not a fruitful source of intelligence on Allied losses.

09:30 The reconnaissance aircraft report weather over the target (as a rule for several targets) and advise the bomber formation as to whether the bombing should be done visually , or by instrument.

09:40 The switching on of “Mickey” equipment indicates that the bombers are pivoting toward the target.

09:50 The formation leader of the first wave gives the order : “Bomb bays open” (clear text or code word).

09:53 Wing after wing gives its bomb release signal. Code words occasionally used for this order varied according to the division.

10:00 The first reports of results are intercepted.

10:00 the first reports of weather over base are heard.

Note: Deciphering of bomber code messages presented no difficulties. They could be read with a depth of only three or four messages. The deciphering was facilitated by the fact that most of the enciphered messages had been previously heard in plain language on R/T. Therefore it was only a problem of organisation to collect this abundant material and to concentrate it in the hands of the duty office without any delay.

Now there is a contrast between the RAF and USAAF procedures during bomber raids on Germany. This is how it was during 1944 when the Germans had organised themselves. Initially they were not at all organised as could be seen when Mosquitos raided Berlin earlier in the campaign and bombed it when Goebbels was publicly promising to eat his hat if a single RAF bomb fell on their capital.

This report must be a composite of how things generally progressed rather than the exact diary of one particular night or day.

The Luftwaffe signals intelligence was acting as an early warning system for air raids , the defences such as flak and fighters were controlled by other parts of the Luftwaffe but now it is possible to reconcile one of the PoW’s statements that no raid ever came as a surprise with the mechanics of how the formations were tracked. There are no indications in these reports as to whether the Allies knew how much intelligence the Germans were picking up from their radio transmissions and even if they did , did they try to stop it. It is not so easy to hide hundreds of planes flying in formation.

If you can remember the old wartime films about the raids , there were attempts at deception by trying to disguise the course of the bombers but they were obviously not successful.
 

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