Luftnachrichten Abteilung 350

Organisation

Referat D only sent reports directly to General Staff only during the first two years of the war. At the end of 1942 a liaison team was established in the operations office (Ic) to deal with intercepts originating in the East. The reports produced by the section were highly specialised and essentially unintelligible to the non-specialist, so they were rewritten by the liaison team. The team had 10 members, who were generally highly qualified. The Referat had a large cryptanalysis platoon attached to it, consisting of around 90 men at the height of the war. But its importance dwindled in the last years of the war, as Soviet cryptographic systems became ever more individual in character and centralized cryptanalysis of the intercept was found to be impractical.^[38]

Also attached to the unit was a large radio intercept platoon which monitored point-to-point networks in the Soviet Union rear defence zones. An intercept company located in Rzeszów forwarded intercepts by teleprinter to the Referat, who sent them to the cryptanalysis platoon to be deciphered. The second main source of the reports was teleprinted summaries from three intercepts in battalions in the east. From 1943 onwards, R/T traffic from Soviet tactical aviation units increased in significance, even being important to final evaluation. During the latter years of the war, it was particularly important on the northern sector where the availability of good landline communications limited the use of radio.^[39]

Meldekopf Warsaw

The Meldekopf in Warsaw consisted of a team of 10 specialists. As Soviet long-range bombers were active only at night, both its radio operators and evaluations alike were only occupied at night. The unit intercepted traffic on all known bomber frequencies and was reported to the nearest ZAF as an early warning. The Luftwaffe considered neither the radio discipline nor the navigation of the Soviet bomber crews to be comparable with the Allied crews in the west. The Meldekopf would report to the ZAF, and to other appropriate HQs, the exact strength, composition, and probable target of enemy bomber formations. This information was determined around the time the Soviet bombers were cross the front lines.^[40]

Training

After a few hours of instruction, novice Luftwaffe cryptanalysts were promptly put to work, the solving of which was in various stages of advancement. After a few weeks the novice was then shifted to a new procedure, as part of a mechanical process in a manner that would enable them in time to learn the different methods of solution. The emphasis was on breaking a cypher or code quickly, with matters of theory of secondary importance.^[43]

The advantage of this method was that individuals could learn in the shortest possible time to successfully decipher certain well known systems such as the Bomber Code and the British Main Weather Code. However, these cryptanalysts failed completely when attempting to break a simple, alphabetic, unrecyphered 3 or 4-digit codes, even if an ample depth was available. The long duration of the war, gradually reduced this disadvantage since each analyst eventually had the opportunity of working of entirely different systems.^[43]

In general, experience showed that men over the age of 35 years, made for below average cryptanalysts. Professional people, like academics, e.g. mathematicians and Philologists, with individual exceptions proved unsuitable for practical deciphering work. As a rule, they exhausted themselves in laborious analytical research, only to find later that the cypher or code had already been solved. The best results were achieved with young people who had completed their high school education or had just entered a university.^[44]

General

In contrast to other units and sections of the Chi-Stelle, Referat B maintained a constant and purposeful policy towards its own personnel. When the former Director of the unit was ordered back to the Marstall in mid-1942, his place was taken by a career officer who removed the last vestiges of the civil service regime from the Referat.^[66] Daily conferences and a number of experienced combat officers were brought in and employed to advise the evaluations in the various desks. The personnel of the Referat was now continuously trained, and were accorded all privileges possible with military functions, such as drilling kept to the minimum. As a result, morale in the unit was considered excellent.^[66]

At the end of 1942, some of the personnel was replaced by women auxiliaries. Shortly before the Normandy landings, the Referat consisted of 4 officers, 3 technicians, 45 enlisted me, and 25 auxiliaries.^[66] After the withdrawal from France in August 1944, the Referat was merged with the evaluation company of Signal Regiment West. Personnel was reduced by more than half. At the end of the war, with the advancing Allies, the unit moved to Türkheim in Bavaria when it was subsequently dissolved.^[66]

Organisation

Allied traffic intercepts increased significantly when the RAF expanded from 1942 onwards, and the arrival of American Air Forces in the British Isles.^[67] This resulted in a reorganisation of Referat B, which was gradually implemented during 1942. Later the desks of the Referat were organised to correspond to Allied air unit categories, rather than types of radio traffic. The organisation was as follows:

• Technical evaluation section which evaluated RAF Coastal Command intercept and during the Normandy landings and with air support, evaluated intercepted party traffic.
• Bomber evaluation section, divided into Royal Air Force and United States Army Air Forces desks, which were concerned with the strategic evaluation of this traffic.
• Captured documents, captured signal equipment and navigational aids, evaluation sections.
• Tactical air force radio traffic evaluation desk.

The Referat has its own mimeograph and technical drawing section. The teleprinter and telephone section was operated exclusively by women.^[68]

Evaluation

Referat B was the senior evaluation agency in the west, and evaluated all the work of the signal intelligence units employed in the west and the north.^[69] This consisted of:

• Luftnachrichten-Funkhorch-Regiment West that later became LN Abteilung-Regiment 351
• LN Abteilung-Battalion 357
• LN Abteilung-Battalion 355

The Referat worked with reports forwarded to it from intercept and evaluation companies, and also with the original log sheets and messages. The latter method was used for Radio telegraphy, as the spoken word was always open to interpretation. The material available to the Referat consisted of the following:

• Daily reports from evaluation and some intercept companies, that were sent by teleprinter and in some most cases by radio or courier.^[69]
• Technical and evaluation reports which the intercept companies prepared monthly.^[69]
• Wireless and Radio telegraphy log sheets.^[69]
• Prisoner of war interrogations' reports, reports on captured documents and kit. Reports on BBC broadcasts and other collateral intelligence material. This interpolation of this material was strictly forbidden, and when used, a reference was provided to the source and if this was missing a reprimand from Ic operations to the Referat chief resulted. It was provided to bring a richer background to intelligence reports.^[69]

It was advantageous that personnel of Referat B belonged to Chi-Stelle as intelligence could be report or when necessary refused to be divulged under certain conditions without reference to rank or station. The last two chiefs of the Referat were adroit at using their position to maintain a close check on the evaluation work in the west.^[70] Duplication of work between Referat B and Luftnachrichten-Funkhorch-Regiment West was an ongoing bureaucratic problem and the only considered solution was the merging of the two units, but it was only realized as the result of Allied pressure, when both Referat B and Luftnachrichten-Funkhorch-Regiment West, following a breakthrough by the Allied at Avranches as part of Operation Cobra by the United States 1st Army, retreated from France. Owing to the difficult housing situation within Germany, the Referat and the evaluation company were established in the same house in Limburg. For each case arising, a discussion took place as to whether a special report or appreciation would be written by the Referat or the specific company from Luftnachrichten-Funkhorch-Regiment West.^[70]

Direction of Intercept operations

Outside of final evaluation, the direction of intercept cover in the west and north was the most important task for the Referat. All intercept stations understandably had the desire to monitor only that traffic which yielded results.^[70] The referat had to insure that not only was this traffic covered, but also those frequencies necessary to obtain a correct intelligence estimate.^[70] For example, several intercept companies could only be moved under pressure to monitor point-to-point networks of the RAF and the Allied Expeditionary Air Force, as no tactical messages that could be reported to combat units were intercepted on those networks. However, these networks still had to be monitored, as it was necessary to understand the organisation of Allied air forces.^[71]

With the appearance of new allied units which needed to be monitored, intercept companies found it difficult to burden themselves with the intercept requirements of the new allied units. In that instance, Referat B would intervene, and reorganise the intercept and evaluation companies accordingly, as per need and personnel available.^[71]

In many cases Referat B itself would take over the analysis of new traffic, and only then would they subsequently assign it to the appropriate evaluation company.^[71]

Messages and Reports

The most important headquarters to which the Referat reported were:

• The Luftwaffe General Staff, Oberkommando der Luftwaffe.^[71]
• The Chief Signal Officer of the Luftwaffe, Ferdinand Feichtner.
• The General der Nachrichtenaufklärung, the signals intelligence agency of the Oberkommando der Wehrmacht.
• The B-Dienst, the German Naval Intelligence Service of the Oberkommando der Marine.^[71]
• Luftflotte 5
• Referat C, for those units working in the south.

In many cases reports were also sent to the commander west, Luftflotte 3 and NAAS 5 of Army signals intelligence regiment KONA 5.^[71] The following types of messages and reports were involved:

• Flash reports of important new discoveries, enemy movements of Allied units, that were sent by telephone and teleprinter.^[71]
• A 24-hour daily summary report.^[72]
• Monthly reports comprising 50-60 typewritten pages of exhaustive treatment of all events and developments during the month, complete with maps and illustrative diagrams.^[72]
• Special reports, e.g. on Army-Air Force collaboration during manoeuvres in the Great Britain.^[72]

Moreover, all important information found in captured material was communicated to individual signals intelligence units. The latter received from Referat B all necessary data such as lists of X and Q groups, lists of frequencies, Call signs, abbreviations and so on.^[72]

General

When the importance of the Mediterranean theatre increased in the middle of 1942, the totally incapable director of this Referat was relieved from office at the instigations of General Staff operations, and replaced by the director of Referat B.^[74] At the same time, several experience evaluations were transferred to Referat C in order to mentor and assist new staff and this served to increase morale in the unit. In general, the operational methodology of the unit was similar to units in the west.^[74] In spite of wire communication to Sicily and Greece being considered reliable, the great distances to the Mediterranean theatre presented problems. Tactical evaluation was lacking and daily reports were always 2 days behind schedule.^[74]

Referat C was considered unproductive, inefficient and bureaucratic. During the entire period of its existence it failed to produce a single technical or special report, in spite of the fact there was sufficient material from was activity in the Mediterranean area. In early 1943, the number of personnel in the agency was increased with 20 women auxiliaries, with the emphasis shifted entirely to paper work.^[75] During this period the agency was completed detached from problems in the Mediterranean area.

This condition became worse in 1944-1945 as duty hours were increased, rations became viewer and bombing raids became more frequent. The prevalence of political sycophants, the threat of being sent to the Eastern Front, the threat of transfer via disciplinary action, all served to suppress and curb the agency personnel working 12 hours or more a day. Messages and reports from the retreating signals units in the south became scarcer and scarcer.^[75] After the formation of Luftnachrichten Abteilung 352 in spring 1943, a merger of the Referat and the regimental evaluation company was considered, but never carried out. In February 1945, the unit disbanded, with parts of the unit travelling to Premstätten in Styria and later in Attersee. Although reduced in size, it started to function again under command of a new energetic director. However this was short lived and in May it ceased activity.^[75]

Organisation

Referat C was organised into desks which corresponded to Allied units or activities, e.g. Mediterranean Allied Tactical Air Force (MATAF), 205 Group RAF, long range reconnaissance, radar reporting networks, transport and ferry service, airfield radio tower traffic.^[76] In addition, two other sections, one devoted to press reports and prisoner of war intelligence, and other to point-to-point networks were especially successful. The two sections, in close co-operation, maintained a detailed organisational plan of Mediterranean Allied Air Forces(MAAF), that the Luftwaffe operations office included in its monthly reports.^[76]

The following desks were attached to Referat C:

• Turkey. 3 men revised and edited the material intercepted and evaluated by W-Leit South-east, and prepared weekly and quarter-yearly for operations.^[76]

• Sweden and Free France. Monitored by outstations with monthly reports were forwarded to operations. After the German withdrawal from France, the desk was reintegrated to Referat B.^[76]

• Referat C2. This section was created in 1942, and was engaged in preparing a textbook on the radio, navigational procedures and Call signs of the Royal Air Force, United States Army Air Forces and Russian Air Forces. This textbook has a wide distribution, and all larger signals units were given copies for research. Supplements were produced which kept the work up to date. In mid 1944, the work was abandoned and the personnel transferred to signals outstations.^[76]

An intercept station also existed in the Marstall itself, and was manned by linguists from Referat C and E. Its primary function was to monitor and intercept traffic that indicated a bomber read in the greater Berlin area by the USAAF. As the Marstall was responsible for the allocation of VHF receivers, the equipment in the intercept station was the best of its type.^[77] The proximity of the Referat proved advantageous, as the R/T technicians manned their sets only during a bombing raid and therefore could devote the balance of their time to either evaluation of cryptanalysis.^[77] Flash reports were telephoned to Meldekopf 3 stationed in Wannsee, while final evaluation reports were sent to the ZAF.^[77]

Operations

Each morning the teleprinted material arrived during the previous night from the two signal battalions in Italy and the Balkans,^[77] from the company in Montpellier, outstations in Spain, and later from the ZAF, as well as from those outstations which were authorized to have direct communication with the Referat. The intercepted material was sorted, categorised by the Referat director and distributed to the appropriate desks.^[77] In the course of the afternoon, the desk would check the incoming intercept. If it could be read, it was deciphered, and evaluated immediately. If it could not be, it was sent to cryptanalysis. Deciphered reports were prepared for inclusion in the daily report of the Referat. After being edited by the evaluation officer, the intercept formed the basis for the daily situation conference at which all controversial points were discussed.^[77] It was then Mimeographed and around noon it would be ready for distribution. One copy was sent by courier to the General Staff, the others were mailed to the recipients.

The afternoon as a rule was devoted to the study of incoming reports and a review of log sheets in from the units in the field; maps were prepared and preliminary work done on the monthly report, the distribution of which corresponded in principle to that of Referat B reports.^[77] Correspondence with the regiments and battalions was taken care of, comments from the General Staff were studied and those relevant were passed on to the field units concerned.^[77]

The Referat achieved success in the field of traffic analysis. By means of network diagrams, the organisation of the Allied tactical air forces in Italy was worked out at a time when W-Leit 2, in spite of its greater proximity to the situation and its operational experience with abundant wireless telegraphy (W/T) and R/T reports of XII Tactical Air Command and Department of the Air Force (DAF), was completely helpless.^[78] In general, as clumsiness, distrust and dodging of responsibility characterised the leadership of Referat C. In order to keep its surplus of personnel occupied, ridiculous and unnecessary tasks, involving a labyrinth of paper work were created. As a result, all feeling for conciseness was lost. The majority of members of the Referat, in spite of years of service in the Chi-Stelle, had never seen an out-station. This reluctance to face realities, weakened the influence of the Referat.^[78] In consequence, its options in organisational matters carried little weight within German High Command, and for most part it was limited to special problems of evaluation.^[78]

Liaison

Liaison also was limited to the field of evaluation. Due to the location of the Chi-Stelle and personal acquaintances, especially with Luftwaffe Ic, it was considered excellent.^[78] Prior to the daily conference, any new problems and all the material that had come in the previous night, were discussed by telephone between the Referat and the operations office, Ic of the Luftwaffe. The discussions that took place included Allied air transport and the current air ferry situation reported by Referat B5 in Oberhaching.^[78]

When United States radio stations appeared on airfields in the Poltava area, as US bombers and fighters escort landed in these airfields, following attacks on Germany or Rumania, an evaluator from Referat C was dispatched to Referat D in Warsaw. A large intercept platoon was transferred to Warsaw to monitor this traffic.^[78] However, the results were insignificant and after fourth months the W/T platoon was recalled.^[79]

In 1944, the Referat places a liaison officer with Dulag Luft, that resulted in many pieces of collateral intelligence being collected, as well as important confirmation of previously gathered intelligence.^[79]

In the last months of the war, the Referat was merged with the evaluation company of Regiment South.

General

The overall mission of the Luftwaffe Chi-Stelle on Soviet Front was the interception and identification of the Soviet Air Forces radio traffic.

To accomplish this mission, it was first necessary to determine the types of signal communication being used by the Soviets. For both Wireless telegraphy (WT) and Radiotelephone (RT), the high frequency band was used almost exclusively, the main exception being navigational aids, i.e. radio beacons, which were used on medium frequency. Until the end of 1942, only WT traffic was found, thereafter R/T was also employed, increasingly greatly from 1944 onwards. The Soviets used radar only to a small extent, beginning at the end of 1944. Almost all W/T traffic was encoded or enciphered.^[81]

From Germany’s point of view, all Soviet W/T traffic could theoretically have been intercepted in one centrally located station. However, in practice it was found, as is so often the case, that areas of [skip], interference and natural barriers precluded such a plan and led to the establishment of numerous intercept stations all along the front.^[81]

Cryptanalytic problems were solved by the use of a relatively large number of personnel, not a few of which were capable linguists and could also be used to translate the contents of decoded messages.^[82]

A further problem occasioned by the expansiveness of the front was how to communicate the results of radio intelligence to those units and headquarters which could make the most of. The recipients of such intelligence were the Chi-Stelle, the operations (German: Ic) of the Luftflotten together with their tactical units on the Soviet Front, and the signal intelligence services of the Army and Navy. Therefore, pains had to be taken either to site Chi-Stelle units in the immediate areas of such headquarters or at least in localities where good wire communications was available. Due to the danger of interception, and delays caused by the necessity of enciphering messages, radio was considered only an auxiliary means of communication.^[82]

Problems encountered on the Eastern front were of such a nature that axiomatic Chi-Stelle procedures and processes could often not be put into effect as a whole, but instead usually as a compromise solution.^[82]

Development 1936 to 1941

Evolution of Luftwaffe east signals units from 1936 to 1940

Until the invasion of the Soviet Union on Sunday, 22 June 1941, interception of Soviet radio traffic was accomplished by several fixed outstations, each of which was assigned a prescribed area to monitor. In the summer of 1936, the first of these stations was established in Glindow, Berlin.^[82] During the year between 1937 and 1938, five further stations were established in Breslau, Pulsnitz, Bydgoszcz, Svetloye (Kobbelbude) and Hirschstätten. Each of these fixed outstations did its own preliminary evaluation work, with final evaluation still undertaken at the Chi-Stelle. The stations were operationally controlled by the Chi-Stelle but administratively by a Luftflotten in whose area they were located. Thus the stations in Hirschstätten and Wrocław were assigned to Luftnachrichten Regiment 4, and the remained with Luftnachrichten Regiment 1.^[83]

This policy was a great mistake and remained a point of contention with signals personnel throughout the war. It meant that signals units were subordinated to two unit commanders, and impossible situation from the military point of view. Frequent differences of opinion arose between High Command headquarters, each wishing to be considered as the authority actually controlling the Chi-Stelle. The situation was often intolerable.^[83]

It soon became evident that the personnel and equipment available for the monitoring of Russian radio traffic, that was becoming constantly more extensive and complicated, were not sufficient. The Russian methods of assigning Call signs and frequencies became more and more complex. Special complications resulted from the fact that each Russian air army implemented its own signal procedures and cryptography standards, that according to the ability of the individual Russian signals officers, making it either more or less difficult for the Luftwaffe Chi-Stelle. There were some Soviet air armies, that owing to the incompetence or negligence of the signals officers, were looked upon with a sort of affection by the Chi-Stelle, while there were others whose traffic could only be analysed by bringing to bear all the resources that the Luftwaffe had available.^[83]

The most difficult task of all was intercepts from the northern sector or lack thereof. This was due in part to the fact that good land-line communications existed in the Leningrad throughout the static warfare in that region.^[83]

Owing to ever present personnel problems in the unit, the organisation of the Chi-Stelle unit during 1938 was not significantly expanded in the east. Luftflotten 1 and Luftflotten 4 requested their own signals intelligence unit, and each wished to received signal intercepts directly from the units located in its specified area, and not via the Chi-Stelle.^[84] In order to meet these requirements, W-Leitstellen were created in the summer of 1938 in the immediate vicinity of each Luftlotte concerned. It was intended that these Leitstellen render interim reports to the Luftflotten, while expediting the intercepted material to the Chi-Stelle for further processing. The personnel, cryptanalysts and evaluations were drawn from the fixed signals outstations, and to a lesser extent from the Chi-Stelle. This withdrawal of personnel from an already weak organisation suffering from chronic staff shortages caused a deterioration in the unit, without any commensurate gain to the new entities.^[84]

In the summer of 1939, the Leitstellen, the fixed stations and the mobile intercept companies on the two sectors were combined into signals intelligence battalions of the respective Luftlotte signal regiments.^[84]

Evolution of Luftwaffe east signals units from 1941 to 1943

When Germany invaded Poland, the Luftwaffe signals units in the east were ordered as follows:

• Referat D of the Chi-Stelle
• The 3rd Battalion of Luftnachrichten Regiment 1 consisted of:
  • W-Leit 1 in Bernau
  • Fixed intercept station in Kobbelbude
  • Fixed intercept station in Bromberg, that was transferred from Pulsnitz.^[84]
• The 3rd Battalion of Luftnachrichten Regiment 4 consisted of:
  • W-Leit 4 in Vienna^[85]
  • Fixed intercept station in Breslau
  • Fixed intercept station in Premstätten
  • 10th Company of LNR 4, newly activated and fought at the front during the Polish campaign.^[85]

At the conclusion of the Polish campaign, monitoring of Polish communications was discontinued. Its place was taken by the Balkan countries and Turkey, that were monitored from Vienna, Premstätten and Budapest.^[85]

In 1940 there were few changes. The fixed intercept stations in Bromberg was moved to Warsaw. An intercept station and DF facility was erected in Kirkenes and the station in Budapest established a satellite outstation in Constanța. A new intercept company called the 9th Company of LNR 4 was activated.^[85]

This situation remained static until the invasion of the Soviet Union.

Signal Intelligence Regiment East organisation

Organisation of LN Abteilung 355

Luftnachrichten Abteilung 355 was activated in September 1944. The need on the part of the subordinate signals units for a more unified operational and administrative chain of command was only realised up to the level of regimental headquarters, and then only realised up to the level of regimental headquarters, and then only on paper, as the Chi-Stelle still continued to traffic directly with subordinate units of the regiment.^[85] The regiment still suffered from divided control, operationally subordinated to the Chi-Stelle, and administratively to the Chief Signal Officer through Generalmajor Willi Klemme, who was not a specialist administrative officer.^[86]

Luftnachrichten Abteilung 353 was organised as follows:

• Regimental headquarters with the 25th Evaluation Company and 12th Intercept Company in Cottbus
• 1st Battalion (north), formerly the 3rd Battalion of LNR 1, with four companies in East Prussia.
• 2nd Battalion (centre), formerly Signals Battalion East with five companies in Poland.
• 3rd Battalion (south), formerly the 3rd Battalion of LNR 4, with five companies in Austria.^[86]

All the battalions had numerous intercept and DF outstations along the entire front.^[86]

Owing to the Soviet advances, the regimental staff together with the 25th and 12th Companies moved to Dresden in mid February 1945. From there as the Allies advanced into Germany, the group retired to Alpine Redoubt. In order to ensure the continuity of operations, a platoon of about 70 signals personnel were formed, comprising evaluators, intercepts and communication personnel. The platoon was fully mobile, and carried the most necessary records and sufficient radio equipment for monitoring and communications purposes. It drove to Wagrain in the Northern Limestone Alps.^[86] The regimental headquarters and companies followed more slowly as they were not fully mobile.

In Wagrain, the 2nd and 3rd Battalions joined the regiment, so that with the exception of the 1st Battalion, that remained in north Germany, the regiment was reassembled.^[86]

After the surrender of Germany, the regiment proceeded via Zell am See and the Lake Chiemsee to the Luftwaffe concentration area at Aschbach in Austria. It was subsequently discharged.^[87]

Intercept and DF Operations

Line of withdrawal of Luftwaffe signal units from the east

In the autumn of 1940, the construction of a large Rhombic antenna system was started, and once in operation, was to orientated to the east and south-east, for the purposes of exploring the possibilities of a central high frequency intercept stations. It was put into operations only shortly before the outbreak of the war with the Soviet Union in 1941 and good results were obtained. However it was never fully manned.^[87]

The distribution of intercept receivers by type for the various monitoring tasks was made on a basis of the preferences of the individual signals units. It proved most advantageous, wherever possible, to assign a complete monitoring mission to a single company or outstation.^[87]

Great use was found for the HF DF, A-10F that used an Adcock antenna type. However, for a war of movement it had to be made mobile. A good DF baseline, as well as an efficient method of controlling the operations of the DF's, was essential to the accomplishment of the regiment's mission. Special care had to be taken in planning D/F control by radio, which of course involved the encoding and decoding of messages, every second counted. The assignment of several targets to one D/F station proved unworkable.^[87]

Cryptanalysis

The problem of securing sufficient and well qualified cryptanalyst personnel was at all times very great, since almost all messages, that numbered between 1000-2000 per day, were enciphered. To mitigate this problem, Chi-Stelle attempted to produce and train cryptanalysts itself. It was found that cryptanalysis skills were an inborn talent, and approximately one half of the personnel trained were proved useful. The chief reason why there were never sufficient cryptanalysts available may be laid to a tendency on the part of those men to specialise in certain types of codes and ciphers. It was also usually impractical to detach cryptanalysts to the various intercept companies, which in the interested of tactical evaluation would be advantageous.^[88]

Cryptanalysts were mostly employed in the W-Leitstellen, or in evaluation companies where they, as well as evaluation personnel were in close contact of Referat E, that suffered a chronic shortage of staff. The introduction of new codes and new recipher table for old codes presented constant challenges for the cryptanalysts.^[88]

An average of 60% to 70% of the 2-Figure, 3-Figure and 4-Figure messages were solved. 5-Figure messages often required painstaking analysis, and when solved were often not read in time to be of any strategic or tactical value.^[88]

Evaluation

• Traffic and Log Analysis for DF evaluation.^[88]

The principal duties of these sub-sections were the identification of all call signs and frequencies,^[88] and the reconstruction of Russian radio networks.^[89] A corollary duty was to determine the system used by the various Soviet air armies in selecting their call-signs and frequencies and to attempt prediction of those to be used in the future.^[89]

• Tactical and final evaluation

As per traffic analysis, preliminary evaluation was undertaken by a fixed intercept station and the mobile intercept companies. Traffic was the forwarded to the W-Leitstellen or the evaluation companies where the traffic was evaluated, and reports prepared that were sent to the Chi-Stelle, the Luftflotten and the Fliegerkorps. Later these battalion evaluation reports were also sent to the regimental evaluation company, where they were compiled into a comprehensive report from the Chi-Stelle, where they were edited and passed to the Luftwaffe and Wehrmacht HQ.^[89]

Signal Communications

Excellent signal reception was absolutely essential to the Chi-Stelle.^[89] Experience from the Russian Front showed that the dissemination of intelligence from outstations to tactical aviation units had to be accomplished in a matter of minutes, and in some cases, seconds. For this reason, R/T stations of Signals Regiment East were located directly on the aerodrome of German fighter and reconnaissance units, and had direct wire lines to the fighter control centre.^[90] The out-stations were also tied to the teleprinter switchboards of the air bases in order that communication be maintained with the battalion and neighbouring R/T stations. The out-stations did not have the necessary means of installing their own telephone lines. They were furnished by the airbase commander. Radio links to the battalion were also maintained as a standby.^[90]

Liaison with the Army signals

As the external characteristics of Russian radio traffic was not sufficient to identify a group of new traffic as either Red Army or Soviet Air Forces it was necessary to maintain close liaison with the German Army cipher bureau, General der Nachrichtenaufklärung. Of primary importance was liaison between the respective traffic analysis sections and for this purpose Non-commissioned liaison officers were frequently exchanged. During such periods when contact with the Army could not be maintained perhaps due to distances involved, the Luftwaffe Chi-Stelle was still able to identify traffic and execute traffic analysis.^[90]

Development up to the Luftwaffe invasion of Russia

In May 1941, Luftflotte 2 and its attached signals units, the 3rd Battalion of the Luftwaffe Signal Regiment was transferred to Warsaw. As the signals unit has no experience in monitoring and intercepting Russian traffic, the majority of the work was undertaken by the fixed station in Warsaw. The committent of the Warsaw station increased again when W-Leit 2 was transferred to Italy in December 1942.^[91] To reinforce the Warsaw station, that was not fully prepared, W-Leit 1 in Bernau, seconded approximately one-third of its cryptanalysis and evaluation personnel to the Warsaw station.^[91] In the last half of 1944, the work of W-Leit 1 has attained such stature that its reports were forwarded by Referat D to the General Staff virtually unaltered.

Shortly before the beginning of the war with the Soviet Union, the 3rd Battalion of LNR 1 in Bernau moved with the Luftflotte to Königsberg. At the outbreak of World War 2, the battalion was composed of:^[91]

• W-Leit 1
• Fixed station in Kobbelbude, with several out-stations
• A small intercept and DF station in Kirkenes

In addition, the Fliegerkorps subordinated to Luftflotte 1 had a signals company that monitored Russian air activity that was of specific interest to the unit. This company, was lacking in experienced personnel, was considered inefficient and to a great extent had to rely upon the support of the battalion. Much later in the war, it was amalgamated into battalion.^[92]

These signals units were linked together by wired communications lines, to the Luftflotte that was only a few kilometres distant, the fixed intercept station in Warsaw, the Chi-Stelle station itself and the advanced echelon which had moved to East Prussia.^[92]

The order of battle and strength of Russian air units were already known from work done during peace time, with all signals people being alerted during the night of 21 June 1941 as to what they might expect to find in Russian radio traffic. However no change occurred in call signs, frequencies of transmission, codes or ciphers. Nevertheless, there was much chaos and confusion manifested in the great amount of plain text messages that was received, The state of readiness gradually improved, but lasted for several weeks, and can be attributed to the continuous withdrawal of the Russians. Radio traffic was not as plentiful as Chi-Stelle wished, the reason being that satisfactory land lines on the northern sector.^[92]

Operations

As Germany advanced into the Soviet Union in July 1941, Luftflotte 1 and W-Leit 1 moved to Dvinsk in Latvia. As it became increasingly evident that personnel and equipment was not sufficient for task at hand, a request to increase the strength of the battalion was submitted, and in the middle of July 1941 and signals company arrived. This company had had previous experience in the East in 1939, and became operational in a few weeks.^[93]

After a three-week stay in Dvinsk, the battalion moved in Luftflotte 1 to Ostrov. Another company was created out of existing personnel, such that from August 1942 to December 1942, the battalion consisted of the following units:^[93]

• W-Leit 1
• Two intercept companies in the direct vicinity of W-Leit 1, together with satellite out-stations and DF units.
• Fixed intercept station in Kobbelbude.
• Smaller fixed station in Kirkenes.

A small intercept station in Mikkeli, with two out-stations, one in central Finland, the other on Lake Ladoga.^[93] This station was created after the entry of Finland into the war, and lengthened the DF base line.^[93]

Use was also made of the Finnish Signals Intelligence Office, Viestitiedustelutoimisto, whose work was considered to be of a high standard within the German cryptography community. The Luftwaffe station in Finland had either wire or radio links with W-Leit 1 in Ostrov. Additional DF equipment was established on the northern sector in order to obtain more favourable DF cuts. Some of these were placed within the area of the central sector.^[93]

During the period of transition, by augmenting its personnel in order to meet the increasing demands made upon it, the battalion was able to provided a flawless picture of the Soviet Air Force in the northern sector.^[94]

In early 1941, owing to administration difficulties and problems with billets, part of the Luftflotte, including the operations office, and the signals battalion, moved from their location in Ostrov to Riga in Latvia. In Riga, W-Leit 1 was located close to the Luftflotte, while the two intercept companies were positioned to the east of the city.^[94]

In autumn 1942, the Luftflotte withdrew to East Prussia, close to Kobbelbude, were the fixed intercept station was located. In February 1945, advancing Soviet troops forced the battalion to withdraw, via land and sea to the island of Rügen. The stations in Finland were closed, and the personnel withdrawn. In January 1945, the battalion returned to Lübeck where it surrendered to the British Army.^[94]

Intercept

W/T interception was the most important in the first stages of the war. The area covered extended from the Arctic Sea to a region slightly north of Moscow.^[94]

In the autumn of 1942, the battalion started to take an interested in Russian High frequency R/T, as this traffic was becoming more prevalent as the war progressed. Two R/T stations were established on German fighter airfields, one south of Leningrad, the other south-west of Lake Ilmen. This was done primarily to increase the rapidity with which these units received intelligence derived from Russian fighter traffic. However it was found that from 1942 onwards that careful processing of RT traffic afforded valuable information on the strength and order of battle of Russian Air Force.^[94]

When the battalion withdrew to East Prussia in June 1944 these two outstations were left behind. A few months later it became necessary to setup still another RT detachment in Courland. Later, the two out-stations left in Russia also withdrew to this area, and continued operations even though Courland was cut off. Part of the personnel of these RT detachments later fell into Russian hands.

The battalion was responsible for covering the traffic of the Russian Baltic Fleet Air Arm. To assist in this task an RT detachment was placed aboard the German cruiser Prinze Eugen. This RT unit followed the activities of the Russian Baltic Fleet aircraft in order to warn German shipping of impending attack. This work assumed even greater importance after Courland had been cut off and was relying mainly on supplies by sea.^[95]

With autumn 1944 approaching, RT intercept had far surpassed WT in importance and was supplying 70%-80% percent of the intelligence obtained by the battalion. The Russian 1st, 3rd and 15th Air Armies used RT almost exclusively, which meant that at least one RT out-station had to be allocated to cover each of these air armies. Good communication between these detachments and the battalion were therefore of the essence.^[95]

Russian radar stations on the northern sector were located mainly in the Leningrad-Kronstadt-Levansaari area, and later on also along the Baltic coast, especially in the Revel and Kemel areas. Two radar intercept detachments were allocated to the battalions by the Radar Intercept Control Centre in Berlin, and these units monitored Russian radar activity in the Leningrad area from April 1943 to June 1944.^[96]

In March 1945, Russian radar stations began to use RT for reporting purposes. During Russian daylight fighter sweeps the fighter control stations were informed of any German fighter reaction as revealed by radar. The signals out-stations monitoring this traffic were able to warn German aircraft of their impending danger.^[96]

Evaluation

Signals was a unique and therefore important source of intelligence to the Luftwaffe. Movements of Russian units, occupation of airfields, number of serviceable aircraft, and location of supply dumps were determined from the monitoring of point to point traffic. Russian offensive intentions were also determined from traffic intercepted on these networks. Thus, for example, a Russian order to bomber units was intercepting ordering an attack on Shavli in Lithuania, where an entire German Panzer Army had been immobilised through lack of fuel. The signals reported this to the Luftwaffe, which provided fighters for the intercept of the Russian bombers, while Junkers Ju 52s dropped gasoline containers to the encircled army. Such signals successes occurred from time to time.^[96]

With the stabilizing of the northern front the volume of Soviet radio traffic shrank. Nevertheless, a substantial amount of messages still were intercepted daily. Signals was almost the only source of intelligence on the Russian situation, as agent’s reports, and other forms of intelligence were for the most part lacking.^[96]

On occasion, the signals battalion furnished intelligence to the Luftwaffe operations which went unheeded, e.g. in the autumn of 1941, when Germany was striving to effect a junction with the Finnish troops at Tikhvin, certain radio characteristics appeared in traffic on this sector that two weeks previously had been noted in traffic from Siberia. This was taken by signals intelligence as an indication that the Russian troops had been transferred in this short interval from Siberia to a sector south of Tichvin.^[97] The German command maintained that this was impossible, and did not react to this intelligence. The Russians attacked in great force and won a significant victory. The railway between Leningrad and Moscow was thus liberated by the Russians, and the Germans were forced to take up positions on the Volkhov Front, leaving the hedgehog redoubt of Demyansk to its fate. The junction with the Finns never materialised.^[97]

The signals station in Kirkenes which suffered with the Finnish SI station from auroral interference in its radio reception, nevertheless derived satisfactory intelligence from for the German headquarters on the Kurmansk Front, especially that concerning convoys and to and from Archangel. The latter were reported to the bomber units and the navy.^[97]

Similarly successful were the Finnish signals stations in monitoring the Finnish Front and the northern sector of the Leningrad Front. The Finnish and German signals worked in closest cooperation.^[97]

Liaison

Even before the start of the war, the commanding officer of the battalion had maintained unofficial liaison with the army and navy signals unit. Frequent visits were exchanged which resulted in a reciprocity of intelligence exchange.^[97] This liaison became closer as time went on, and all three branches of the Wehrmacht were able to give each other very important intelligence, and avoid unnecessary duplication of work. Naturally close liaison was also currently maintained with the other Luftwaffe signals battalions on the Eastern Front.^[98]

Prisoner of War interrogation

Since the signals battalions had a considerable number of Russian speaking interpreters, who knew the Russian mind and its weakness, permission was secured for these interpreters to be present during interrogation of captured Russian pilots and radio operators. As the prisoners had been taught by Russian propaganda to expect the worse possible treatment, considerate handling of them often brought results. Good food, a glass of vodka, and a cigarette soon made then loquacious. The only drawback was that they did not know much, since the Russian policy, in interests of security, was that each man should be given only that information needed to perform his individual job. Since only the formation leaders had radio transmitters, and the navigator of the leading aircraft performed his speciality for the entire formation, the other crew members knew nothing. The radio operator also possessed no knowledge of anything but his radio set. Code and ciphers were held in a safe by an especially appointed officer and only made available to the formation leaders shortly before take-off. By order, radio was to be used as little as possible; navigational aids did not exist. Therefore, relatively little intelligence could be obtained on Russian signal techniques. Prisoner of war statements gave a quite a complete picture of ground organisation, composition of tactical units and so on.^[98]

Organisation and development

Before the start of the Eastern campaign, the fixed signals stations in Warsaw, W-21 worked on traffic of the Russian Air Force. When war in the east became imminent, W-Leit 2 also was moved to Warsaw with Luftflotte 2 as reinforcement for the expected military operations. Up to the time of the move, W-Leit 2 had worked on British air traffic exclusively. Since it was inexperienced in Russian traffic, the full monitoring burden fell upon W-21 during the first months of the great offensive in the east. Conditions were made very difficult through lack of sufficient personnel and transport, as the campaign was then moving very fast.^[99]

W-21 and W-Leit 2 were moved from Warsaw to Minsk and later in October 1941 to Smolensk. In December 1941, Luftflotte 2 and its signals battalions were withdrawn and sent to Italy.^[99]

W-21 and the signals company of V Fliegerkorps had to cover all of the central sector Russian air traffic during the severe winter of 1941-1942, under the most difficult conditions. This coverage was performed from Smolensk. Due to difficulties in administrations of the signals company of V Fliegerkorps and W-21, it was decided to combine them and form the Signals Battalion, East. At this time the Fliegerkorps V changed its name to Luftflotte east.^[99]

The signals battalion furnished all its intelligence reports to Luftflotte operations, and worked directly under the Chief Signal Officer of the Luftflotte Staff.^[99]

In Smolensk there was also a German Army signals regiment. This regiment covered Russian Air Force traffic. The coverage of air traffic by this regiment was even greater than that of the Luftwaffe signals intelligence. Every effort was made by the battalion to rectify this matter, and in course of four months this was accomplished through additional intercept personnel, transfer of the intercept site to an area of better reception, retraining of personnel, and reorganisation of and closer cooperation between the evaluation, deciphering and intercept elements. In September 1942, the army signals ceased monitoring Russian Air Force traffic, and all intelligence reports on the Russian Air Force were handled by the battalion.^[100]

The coverage of the battalion increased so rapidly that in a very short time, it was unable to cover all commitments without having again to increase personnel and equipment. These commitments arose from air-to-ground traffic, which up to this time had not been covered. It necessitated the creation of a DF network, RT outstations and a fighter warning service for German long range reconnaissance. The ensuring requests for additional personnel and equipment were granted, in most cases by the Luftflotte in consideration of the importance of the mission and the value attached to signals reports. At this time the battalion compromised two intercept companies and one Evaluation Company. Only one of the companies was fully mobile, the other two had only a minimum of vehicles.^[100]

When the bulge in the German line in front of Smolensk was eliminated by the Russians, the battalion together with the now renamed Luftflotte 6 moved to Orsha in August 1943, and two weeks later again moved, this time to Minsk.^[101]

In Minsk, the battalion was ideally located in a large school and enjoyed excellent radio reception. The move was made in echelons, and coverage of Russian traffic was carried on during the move. The battalion functioned very smoothly, and took little time to become completely operational at the new location (Fig 4).^[101]

During October 1943 in Minsk, the battalion received a fourth company. This intercept company was formerly with a Fliegerkorps on the southern sector, and was fully mobile. The addition of this intercept company enabled the use of fifty-five receivers on Russian WT traffic.^[101]

Each of the companies in the battalion had its allotted work. The 1st company was charged with all deciphering and evaluation. The 2nd company was assigned coverage of Russian air force point to point networks. Between 500 and 900 messages were intercepted daily, which were processed by the 1st company and read with 60-70% success. The 3rd company monitored Russian long range bomber traffic. For fighter traffic RT outstations of this company were attached to German fighter units and worked on at the latter's bases. The 4th company monitored the Soviet Air Defence Forces (PVO). This involved WT and RT traffic of the Russian fighter arm defending critical railway junctions and industrial centres. Also monitored were the flak and air raid warning networks, radio beacons, and radar. The RT outstations also warned German long-range reconnaissance aircraft of the approach of Russian fighters. The work in Minsk continued for about 10 months and was considered very successful.^[101]

In June 1944, the battalion moved with Luftflotte 6 from Minsk to Warsaw and in August to the vicinity of Łódź. While there, a fifth intercept company was added and the battalion was fully employed for another six months. [ Fig no. 5].^[102]

The chain of command of signals battalions, was generally changed several time during the war without attaining a satisfactory solution. Even the final reorganisation into signals regiments, with separate operational and administrative commands over them, did not prove at all successful.^[102]

The Fliegerkorps organisation and Luftflotten Ic operation, several times attempted to have the signals units serving them subordinated to them, rather than the signal corps, as these units were their prime source of intelligence. The realisation of such a plan which met with stiff resistance in signal quarters might have had a detrimental effect on the work of signals intelligence, since a not inconsiderable part of this service devoted itself to the interests of combat units rather than to those of the Ic operations. Moreover, a signals battalion with its radio receivers, DF and other signal equipment would have proved too much of a technical problem for Ic.^[102]

Signals Intelligence Battalion East grew with increased volume of Russian traffic, but from the very first was always able to solve the intricate problems presented. Lack of caution was in no small way responsible for many problems and the following illustrates the point. A certain German general, in a public interview, told the press that his success in breaking out of an encirclement by Russian troops was directly attributable to knowledge of the disposition of opposing Russian forces, obtained from signal intelligence.^[102]

The effect of this interview was directly felt by the Chi-Stelle as such declarations inevitably brought about a complete change of Russian codes and cyphers.Despite these difficulties, signals was able to surmount all problems, owing largely to the fact that from the beginning it had followed Russian forces most closely, and could again pick up the threads, even following such drastic changes.^[103]

The battalion was always given the utmost consideration in its equipment and personnel needs, by the Luftflotte. Several times the Luftflotte commander himself came to the assistance of the battalion, owing to his great interest in the work.^[103]

Operations

Liaison

Organisation and development

Operations

Soviet Grid Systems

All messages in which names of localities were given in grid reference were handled by a grid specialist.^[126]

Soviet grid references were usually expressed by a 6-figure group with a letter frequently added. The reference was often used to inform Soviet air units of the bomb line. Since the operational sectors of the individual soviet units were known, and since the Soviet and German front lines were both the same, an entry into the grid system was easily accomplished.^[127] The breaking of the map code was further facilitated by the fact that the soviets, in order to specify a location exactly, often put the first, or the first and last name at the end of the figure group e.g. Mykolaiv 412312N, Tarnov 52394Tv.^[126] Another point of entry into breaking these grid references was that in the case of a string of encoded locations a reference to terrain elevation was usually left uncoded.^[127]

The two most prevalent grid systems were:

• Enciphered longitudinal and latitudinal references, used in connection with small-scale maps and valid for the entire Eastern Front.^[127]

• The Gauss–Krüger coordinate system in connection with large scale maps, used only on certain sectors of the front.^[127]

The first system was used by the Soviet Air Raid Warning Service, and by the long range bombers, while the second was used by the tactical aviation units, and had many variations.^[128]

Fig No 1. Soviet Grid System during World War II

The following is an example of the Air Raid Warning System; the entire map was divided into large, small and smaller squares. A large square consisting of 1 degree of longitude and 0.5 degrees of latitude. Longitude and latitude references were expressed in a code, which usually changed monthly. A large square was divided into nine small squares, while they in turn were subdivided into four smallest squares. A single digit was used to designate the small and smallest squares. These numbers for the squares remained constant and ran clockwise, beginning in the upper left hand corner. Longitude and latitude references of the large square expressed by the coordinated of its upper and left hand corner. Thus as show in [Figure no 1], the encoded references for the city of Poltava would be 465262.^[127]

The Gauss-Krüger system was a design for a much smaller grid, the primary difference being that the dimensions of the largest squares were selected arbitrarily by the individual units using the system.^[127] From the Chi-Stelle standpoint, the size of these squares could be determined only through experience.^[128] The system of numbering the small and smallest squares was the same.^[128]

The method of encoding the coordinates used to designate a large square varied with each Soviet air army, and often with units within the air army. Further difficulties for the agency were exposed by the fact that the coded equivalents for longitude and latitude did not always run regularly from west to east and north to south, but occasionally in the opposite order; also some units might choose to use all even numbers, while other units chosen odd numbers.^[128]

In some systems the large squares were not encoded by number, but with a code name, e.g. lipa for Linden tree, and the encoded reference wouldn’t read as 425391 but lipa 91.^[128]

In another grid system, longitude was expressed by a double 2 digit number, and latitude by three. The next reference referred to the smallest square, the small square being omitted, thus, this system still resulted in a 6-digit reference. This grid was used only in conjunction with large-scale maps.^[128]

Prearranged Form Messages

Soviet pre-arranged form messages were handled by an individual specialist belonging to the evaluation company. Some messages had the characteristics, in which they differed from other types of traffic:

• They contained in the clear, the words pervoe (firstly) Vtoroe (secondly) tretie (thirdly) and so on in numerical ascendancy, indicating the type of report being rendered.
• They contained numbers in consecutive order, which indicated the subject of which was rendered.^[129]
• These were followed by groups of irregular numbers, which indicated the strength of personnel, weight or quantity of equipment.^[129]

The following is an example of a typical prearranged form message.

Pre-arranged Form Messages
Message	pervoe	03			835
Meaning	On hand	High octane fuel			835	Kilos
Message	04	1620	05		000
Meaning	Motor fuel	1620 Kilos	Oil		0	Kilos
Message	06	11350	07		4800
Meaning	M/G ammo	11350 rounds	A/C ammo		4800	Rounds
Message	vtoroe	03			1560
Meaning	Required	High octane fuel			1560	Kilos
Message	04	730	05		200
Meaning	Motor fuel	730 Kilos	Oil		200	Kilos
Message	06	11500	07		2300
Meaning	M/G ammo	11500 rounds	A/C ammo		23000	Rounds

Daily reports of this type indicating stocks of rations, ammunition and fuel, condition of airfields, changes in personnel strength, were made by subordinate units to the senior HQ’s.^[129]

Prearranged form messages of combat aviation units contained, for the most part, details as to strength, location, operational status of aircraft and crews^[129] and seldom gave any information as to operations, duration of flights or losses. Any grid locations mentioned in such messages were encoded. The following is an example of such a message:^[130]

Pre-arranged Form Messages for Aviation Combat Units
Message	01	195		02
Meaning	regiment	195		location
Message	524313	03		31
Meaning	Ivanovka	aircraft		31
Message	365	04		25
Meaning	type IL-2	serviceable		25
Message	05	6	07	34
Meaning	unserviceable	6	pilots	34
Message	08	37
Meaning	aerial gunners	37

In addition to their valuable contents, these messages were an important aid to the identification of call signs and networks.^[130] Even when call signs were changed daily, a Soviet unit was easily identified through this information as to members of aircraft and crews, and quantities of oil, fuel, ammunition, which were given in the clear. Since the form of these messages usually remained constant for seven to fourteen days, it was necessary to refer to a similar message of the previous day in order to recognise the unit, and therewith to re-identify the call sign.^[130]

Daily summaries and operations reports of combat aviation units were also reported by pre-arranged form messages. Numbers in these messages were encoded, but in such a simple form, however, that speedy analysis was possible.^[130] The digits 0 to 9 were enciphered by 3-digit numbers from a prescribed group of 100 numbers.^[131] For example, 812=1, 816=2, 831=3,854=4 and so on. The various types of aircraft were encoded with other 3-digit numbers from another group of 100 numbers. For example, LA=507, IL-2=513, IL-4=514, A-20=515, Liberator=524, JU=532. Designations of types of units, e.g. fighter aircraft, fighter-bomber, were encoded within another one hundred number group. The code numbers were changed frequently, but the order of meanings within each hundred member groups remained constant. It was therefore usually sufficient to identify one meaning only in order to re-establish the whole sequence of meanings within a hundred number group.^[131]

This system was also used by Soviet long range bomber groups in their strength reports, and by the Soviet Air Raid Warning Service. It was valid for the whole of the eastern front, and therefore of the greatest importance to all the Chi-Stelle battalions which competed with each other in an attempt to be the first to break a new addition of this code.^[131]

Weather Messages

Encoded weather messages were given directly to the weather liaison officer. These could be easily identified by their indicator, by the random use of the letter X within the text of the message, and by the absence of message numbers and delivery groups. Weather messages in sent in clear text, were quite frequent at the beginning of the war but became rarer in later on. These were translated into German before they were forwarded to the liaison officer.^[131]

The weather liaison officer deciphered messages by means of a deciphering table which was broadcast every six hours from the office of the Chief of the Luftwaffe Weather Service.^[131] Weather messages were of assistance in identifying the geographical origin of other traffic intercepted on the same networks, as the weather intercepts often mentioned meteorological stations together with their locations.^[132]