The Luftnachrichten Abteilung 350, abbreviated as OKL/Ln Abt 350 and formerly called the (), was the Signal Intelligence Agency of the German Air Force, the Luftwaffe, before and during World War II.TICOM Volume 5, p. 23 Before November 1944, the unit was the , which was often abbreviated to Chi-Stelle/ObdL or more commonly Chi-Stelle.
The founding of the former agencies of OKL/Ln Abt 350 dates back to the year 1936, when Colonel (later ) Wolfgang Martini instigated the creation of the agency, that was later established on the orders of Hermann Göring, the German politician, head of the air force, and leading member of the Nazi Party.IF-180 Seabourne Report, p. 5 Right from the beginning, the Luftwaffe High Command resolved to make itself entirely independent from the German Army (Heer) in the field of cryptology.I-13 Section II
Background The LN Abt 350 was one of a large number of regiments which were named in that series, but there were several related regiments, which dealt with intelligence-related matters, of one kind or another. These were as follows:
LN Regiment 351. Mapping and interception of communications intelligence of Allied air forces in England and France. It conducted air to air interception, ground to air, and ground to ground including tracking of navigational aids. LN Regiment 352. Mapping and interception of communication intelligence of Allied air forces in the Mediterranean area. LN Regiment 353. Tracking and mapping of the Soviet Air Force. LN Abteilung 355. Allied air forces in northern areas, specifically the Soviet Air Force in Northern Norway. It covered ground to ground, and air to air according to reception conditions. This unit was formerly W-Leit 5 based in Oslo. LN Abteilung 356. Route tracking of Allied air forces by radar interception and in collaboration with LN Regiment 357. LN Abteilung 357. Tracking Allied four-engined formations and route tracking by intercepted signals and in collaboration with LN Abt. 356. LN Abteilung 358. Training of intercept personnel. LN Abteilung 359. radio jamming of Allied communications, but it also conducted deception operations.
Chi-Stelle
Radio Defense Corps
History of operations in the west
Outbreak of the war
General The effect of the outbreak of war was immediately felt by Chi-Stelle, in so far as all participating nations began to transmit the majority of their messages in codes and cyphers. Thus the evaluation of the contents of messages was made more difficult, although the organisation of Allied air forces, as such, that were already known, could be built up from intelligence on hand. Newly activated units were identified on the basis of existing tables of organisation. In the early months of the war in France only the movements of bomber and reconnaissance units could be determined since the fighter arm could only be followed by monitoring RT traffic.IF-181, p.20
The Invasion of Poland only lasted 18 days and was over too quickly for signals intelligence to play a part in it. However the Invasion of France and Invasion of Russia were preceded by a long preparatory period in which the respective Leitstelle found time to familiarise themselves with Allied procedure. Also by virtue of existing reserves, it was possible to concentrate the bulk of available resources on a single opponent.
Organisation With the outbreak of the war only two battalions were established for use in the west: W-Leit 2 and W-Leit 3 and these were immediately committed. Both battalions had substantial difficulties to contend with, e.g. the shortage of officers was so acute that two intercept companies had to be commanded jointly by one officer. The position of the Leitstellen at Luftflotte Headquarters was a difficult one. Contributory factors was the complete unfamiliarity of the Leitstellen commanders with Signal Intelligence processes that included the strict security of own processes that the Chi-Stelle operated on. Even the flying units of the Luftflotten that were interested only in combat, regarded signal intelligence with much scepticism. The first break in this wall of distrust was achieved through the results of monitoring Allied RT fighter traffic.IF-181, p.21
In order to combat raids by French fighter aircraft on Germany. Individual intercept detachments were formed from the companies under W-Leit 3 to intercept the fighters RT traffic. On their own initiative these detachments sought contact with German fighter units, to whom they communicated their observations by telephone. As the French fighter pilots talked excessively while flying, a great deal of valuable information was provided to traffic intercepts captured by German fighter control, especially since the detachments were equipped with Direction finding (DF) equipment that could pinpoint French fighters. The successes of Staffel and Gruppen working together with signals detachments in shooting down Allied aircraft to such an extent that Chi-Stelle became an esteemed agency whose intelligence was valued by the German Fighter Command.
The British night attacks on Germany began in the first months of 1940. Usually the British bombers flew to Le Bourget during the afternoon, and then took off from there at night, flying as far as the Prague area. Their route was followed closely by intercept stations W-Leit 2 and W-Leit 3 through taking DF bearings on air-to-air traffic and from pilots, speaking freely. They flights were for propaganda and training purposes, during which leaflets were dropped.IF-181 p.22
Neither in the six-weeks long Battle of France was it possible for Chi-Stelle or signals to distinguish themselves, owing to the speedy sequence of events. An exception was the intercept detachments of the 9th and 10th Companies under W-Leit 3 that worked in cooperation with German fighter units. At the end of the Battle of France, W-Leit 3 moved to La Celle-Saint-Cloud, the 9th Company to Deauville, the 10th to Saint-Malo, W-23 to Brest and W-33 to La Celle-Saint-Cloud. W-Leit 2 had already moved during the campaign with W-12 to the vicinity of Brussels and from there dispatched an intercept platoon to Wissant. The platoon covered No. 11 Group RAF in England. At times the large scale operations of the German Luftwaffe against England in autumn 1940 were directed from its intercept room. Here the technical importance of signals became indisputably apparent for the first time. Unfortunately W-Leit 2 was transferred to the East, early in 1941 and the platoon subsequently fell to the lot of W-Leit 3. Requests for personnel and equipment were continually ignored by W-Leit 3, which could not overlook the fact that its own intercept companies had been overshadowed by this platoon.
The tactical successes achieved by signals intercept that benefited fighter units also brought a more favourable relationship between signals and headquarters and this included Chi-Stelle, that became renowned. Of course the unfortunate internal politics played with the key positions of the service and this prevented a steady growth in the unit. The Luftwaffe at that time contained too many rough edges and contradictions, and despite all its supposed veneer of modernity, it was still burdened with too much inveterate Prussianism to be capable of instituting radical changes directly following great successes. Thus, those young successful soldiers did not become the decisive factor in the next period of signals development, but rather the old reserve and career officers, unfamiliar with signals work, who held key positions by virtue of their rank and age and whose paralysing and often destructive influence was characteristic of the Signal Intelligence Service in the west.IF-181 p.23
Training Although civilian employees had been trained in Army intercept stations during peacetime, the signals training of military personnel was totally neglected. Therefore, when the number of personnel increased tenfold in the early months of the war, newcomers received little training and had to develop their own ideas and methods independently. In order to remedy this intolerable situation, a signals school was created under the control of W-Leit 3, in which radio operators and evaluators were given the experience necessary for their profession.
Mid 1940 General
The surprisingly quick collapse of the Allies in the French campaign of 1940 offered little opportunities for signals to expand. Few staff officers realised the importance of immediate evaluation of intercepted message traffic. Tactical and strategic evaluation of signal intelligence was in its infancy, on the one hand because competent signals officers were themselves not aware of its possibilities and on the other hand, because headquarters were orientated to regard Chi-Stelle in the same breath as they did secret agents.
Organisation
An insight into signals development in 1940 can be determined from the following facts.
Signals intelligence was made available only to the Luftwaffe Operations staff and to Luftflotte headquarters. Any liaison with flying units was forbidden by General Wolfgang Martini on the grounds of security. General staff were often incapable of comprehending this new form of intelligence and were distrustful of it. Consequently, Signal Corps personnel found it difficult to offer advice to headquarters. Only after a long period of trial was Chi-Stelle able to win representation for itself at command posts and at headquarter staffs.IF-181 p.25 The assignment of the signal battalions to the individual Luftflotten caused a certain disunity in respect to personnel and equipment. The Chi-Stelle which at the time still clung its peace-time traditions was unable to assume the overall direction of operations as it was still short of operational experience. A shortage of signals officers existed. A great shortage of technically qualified personnel existed. The new personnel who were being continually received for training by signals, consisted mostly of academic students and linguists among whom were seldom people with a technical interest. General Martini was unable to produce a carefully planned policy regarding personnel. To these were added the following operational difficulties: The battalions were administratively subordinate to Chief Signals Officers of the Luftflotten and to the regimental commanders who were unfamiliar with this field of work. They received their operational instructions from the Chi-Stelle Referats. The results of this were: The different conceptions on the part of the Luftflotten and their Chief Signal Officers concerning warfare itself and their respective demands upon Signals Intelligence. The refusal of the W-Leitstellen to recognise the corresponding Referat of the Chi-Stelle as the final agency controlling signals intelligence. These W-Leitstellen regarded the Referats of the Chi-Stelle as an unnecessary organisation.
Strength The Signals units located in the west comprised:
{| class="wikitable" ! colspan="2" style="text-align: center;background:LightSteelBlue" | Unit Strength |- |! style="text-align: center;background:#ccc" | Unit | ! style="text-align: center;background:#ccc" | No. of Men |- | 3 W-Leitstellen | style="text-align: center;" | 600 |- | 5 Fixed Signals Stations | style="text-align: center;" | 700 |- | 5 Signals Intelligence companies | style="text-align: center;" | 700 |- | style="text-align: right;background:#ccc"| Total Personnel | style="text-align: center;" | 2000
Locations The W-Leitstellen were located either at or near Luftflotten headquarters. The fixed signals intercept stations moved more slowly. Signals companies were already established on the coast of Netherlands, Belgium and France. Each company and fixed intercept station had a WT and RT platoon as well as an evaluation section and its own DF unit.IF-181 p.26
Evaluation