Cipher Department of the High Command of the Luftwaffe was the signals intelligence and cryptanalytic agency of the German Air Ministry before and during World War II. In 1945, the unit was known as the Luftnachrichten Abteilung 350, abbreviated as OKL/Ln Abt 350 and formerly called the (). It was the successor in November 1944 of the unit formerly named as the Chi-Stelle Ob.d.L. (), which was often abbreviated to Chi-Stelle/ObdL.
History
As early as 1935, civilian employees of the Luftwaffe had been sent to fixed intercept stations of the German Army for training. A Luftwaffe officer, a technician and a civilian inspector who has been associated with the German Army Intelligence Service during World War I were transferred to the Luftwaffe Chi-Stelle. The two people canvassed for assistants among their old circle of acquaintances, former soldiers who had served in World War I as intercept technicians or cryptanalysts. Their numbers were no means sufficient for the task at hand.IF-180 Seabourne Report, p. 5 They consisted of people who at one time, either in civilian or military life, had received radio training or who were fluent in foreign languages. Among them were old soldiers, former seamen, professional travellers, adventurers and political refugees. In contrast to the Army, security measures taken in admitting people to the Agency were superficial, and a great number were found to be of questionable character. These trainees made training more difficult. Owing to their privileged position, they had a derogatory influence on the Luftwaffe Agency.IF-181 p. 16
In creating the Chi-Stelle, the fundamental error was committing to choosing personnel indiscriminately, without any regard to their previous training for this special work. The civilian employees had training, but no training in Chi-Stelle type of work. The first technical equipment was very deficient. Old receivers from World War I were being used, and the installation alone was a technically difficult task, and therefore naturally unsuitable for the SIS. Even the later-installed multiple dial receivers were in part improvised.IF-181, p. 11 Therefore, the importance of the Chi-Stelle in these first years remained slight, when it should have been assuming operation direction of the Luftwaffe Signal Intelligence Operation.IF-181, p. 14 A small nucleus had been assembled, with independent Luftwaffe intercept experiments begun, and by the summer of 1936, traffic from Italy, Britain, Poland, Czechoslovakia and Russian air forces had been intercepted. The training of radio operations was supervised by a small cadre obtained from the Reichswehr cypher bureau. On 1 January 1937, the agency was officially launched, under the Luftwaffe banner, with one officer and twenty civilians. It was called Chiffrier Stelle.TICOM Volume 5, p. 23 New Luftwaffe fixed intercept stations were founded in Munich, Münster, and Potsdam (Eiche) in 1937 and given the cover name of Weather Radio Receiving Stations () (abbr. W-Stellen). The Luftwaffe fixed intercept stations at first monitored only the air force point-to-point networks taken over by the Army. Since in peacetime, almost all countries sent their radio traffic in plaintext, the work was simple, and direction finding was unknown.IF-181, p. 15 Personnel consisted at first of an officer in charge, two or three technicians and 30–40 civilian employees. Early training flights with the Zeppelin were carried out under the direction of the Chi-Stelle.
Mobile intercept platoons were established at the same time, to operate in the field.IF-189, 403, p. 2Volume 5, p. 9 These small sections, about 10 analysts who undertook evaluation locally, corresponding to the monitoring areas of the three out-stations, were formed. The first dealt with England, France, and Belgium; the second with Italy, and the third with Russia, Poland and Czechoslovakia. To these were added a small cryptanalysis group, that was called the Chi-Stelle which served all three sections.IF-180, p. 2 The intercept stations were supplemented by direction finding stations which were called Weather Research Stations () (abbr. Wo-Stellen), after the start of World War II. The small sections were expanded into mobile Radio Intercept Companies () which collaborated with the fixed stations in the intercept of foreign air force traffic.IF-189, 403, p. 3
Relation to Luftwaffe headquarters
The material sent from the out-stations to the Chi-Stelle Agency was classified according to tactical subject, and passed to the General Staff. Since, at this time, the Chi-Stelle itself was part of the General Staff, and as such was responsible for SIS planning and personnel policy, its importance in this early stage was considerable.I-180, p. 2 The intelligence passed to the General Staff was shared with the Chief of the Air Force, the Army, the Navy, and also the local air force: Luftflotte commanders. The Agency had the further duty of assigning intercept missions to the field units.Volume 5, p. 10 It soon became evident that the intelligence needs of the local air force (Luftflotte) commanders could be more quickly satisfied by having evaluation performed at a lower level than at the Agency. As a result, field evaluation centres of company strength were established and given the cover name of Weather Control Stations () (abbr. W-Leit).IF-181, p. 16
Plan for wartime organization In 1939, after several experiments at reorganization, the fixed and mobile signal intelligence units were combined into Sig Int battalions, removed from the administrative control of Chi-Stelle, and attached to Local Air Force Signal Regiments, in each case as the third battalion of what was primarily a communication regiment. Each signal intelligence battalion was composed of an evaluation unit (the W-Leitstelle), two mobile intercept companies and three fixed intercept stations.IF-189, 403, p. 4 This decentralization of LNA 350 resulted in the Chi-Stelle losing influence, especially at the outset of the war.
In this organization, however, a serious mistake was made in that the above-mentioned companies were not activated immediately and taken under continuous training, as in the Army. Instead, they existed in the form of intercept platoons, which were trained by fixed intercept stations, the men being returned, after only a short period of training, to their radio companies in the Luftwaffe Signal Regiments. In this manner, a trained nucleus of personnel would have been built up before the war, as well as more than a few hundred civilian employees, which could be called upon at the start of the war. The functioning of the LNA 350 in the early months of the war was entirely to the credit of civilian employees, since it was they who had a knowledge of the activities.IF-181, p. 17
Start of World War II
With the start of the war, the Chi-Stelle was already an organisation of some 1400 people. For a whole year prior to the war, the fixed Chi-Stelle stations had been systematically covering the air force traffic of foreign countries. Their work was complemented by revealing press reports and other sources of intelligence, the results being that the High Command, prior to the outbreak of war in September 1939, could be stated as having a quite accurate picture of the air armament, deployment, and strength of foreign air forces, as well as their organisation and expansion.IF-180, p. 4 This intelligence enabled the German Command to quickly defeat the Polish and French Air Forces during the first phase of the war. It also permitted the Chi-Stelle to closely follow the activity of the Royal Air Force (RAF), even after the commencement of hostilities, when the use of efficient cipher systems was immediately adopted.
When war began, each of the Referats (departments) dealing with foreign countries had compiled an opulent background of material on the foreign air force with which it was concerned. The quantity of this material constantly increased, and was studied carefully. Each Referat maintained close contact with its corresponding sub-section in the office of Ic (Operations), while these in turn, lent the Chi-Stelle the benefit of their records and experience. The Referat exercised influence over the operations of the Intercept stations. On the other hand, preserving elasticity and processes in the conduct of operations was rendered more difficult by the profusion of Chi-Stelle and Intercept units activated at the start of World War II.
Organisation At the beginning of 1938, a reorganisation of the Chi-Stelle took place. Referats (departments) were created to correspond to the subsections within the office of the Luftwaffe High Command. Thus they were newly formed or reorganised.IF-180 p. 2
Referat A: Personnel, radio equipment of other countries, procurement of radio equipment, and liaison with the Luftwaffe Procurement Division. Referat B: Great Britain Referat C: France and Italy Referat D: Soviet Union, Poland, Czechoslovakia and the Balkans Referat E: Cryptanalysis Referat F: Direction finding (DF) Evaluation. Referat F disappeared from the organisation in 1940, as common DF evaluation of two countries in such widely different stages of radio development as Great Britain and the Soviet Union proved to be absurd.
With the exception of a few insignificant changes dictated by the military situation, this organisation remained effective until the end of World War II. Progressive planning and innovation took place within the other Referats. After the outbreak of the war, the Referats were brought up to company strength fairly quickly, while the Chi-Stelle itself was elevated to the status of a battalion within the signals regiment serving Luftwaffe HQ.IF-180 p. 3
1940–1941
Referat A
Immediately following the start of the Polish campaign, the Chi-Stelle moved from Berlin to the Neuer Marstall, the former riding academy of Frederick the Great in Potsdam-Wildpark. The Marstall became a sort of second name for the unit since it remained there until just before the German collapse. In other respects, the first six months of the war brought little change to its ministerial methods of working or its relatively extravagant manner of existence. Only by the middle of 1940 did the newly inducted military personnel gain ascendancy over the civil service employees in the Marstall.IF-180 p. 5 The development of the signals battalions assigned to the Luftflotte had been exploited primarily from the military point of view. Since even the signals companies assigned to the individual Fliegerkorps worked independently of the (), moulding their individual activities to conform to the requirements of the combat units they served, the decentralisation of Chi-Stelle at first seemed to be very far reaching.IF-180 p. 6
Thus in the opening phase of the war, the importance of the unit was sharply reduced. The tremendous expansion within Chi had resulted in the employment of untrained personnel, made up in part, of radio operations from the Luftwaffe Signals Corps and in part linguists from other Luftwaffe units who had been transferred into Chi. The intercept stations were placed on their own and had to be prepared to meet the demands made of them. In addition, teething problems presented themselves during the first months of the war, with types of problems that were never conceived during peace-time. For these reasons, the focal point of the Chi-Stelle quite definitely shifted to the W-Leirstellen, and to those intercept stations which were especially favourably situated and capably commanded, considering that Chi-Stelle itself was scarcely more than an administrative office.