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  European Axis Signal Intelligence in World War II

DOCID: 3560829


Washington, D. C.




Declassified and approved for release by NSA on 06-01-2009 pursuant to E.O. 12958, as amended, Declass 58017

Prepared under the direction of the CHIEF, ARMY SECURITY AGENCY1 May 1946WDGAS-14

DOCID: 3560829


The German Air Force Signal Intelligence Service

Chapter I.      The Service in General; Sources of: Information Concerning It

Chapter II.     Development of the German Air Force Signal Intelligence Service

On a whim, I decided to search for declassified documents on the subject of radar, radio, and related communications subjects. Actually finding relevant content takes a bit of work, so I am going to spend some time locating and reproducing some of them here on RF Cafe. Having a repository of readily available reports will make future research a little easier. Government documents, unless otherwise marked, are available for reprint so long as the content is unaltered. Warning: These documents have been processed with optical character recognition (OCR) software and might contain errors.

A World War II German Army Field Cipher and
   How We Broke It

Adversary Agent Radios

Agent Radio Operation During World War II

European Axis Signal Intelligence in World War II

German Clandestine Activities in South America
   in World War II

NSA and the Cuban Missile Crisis - Shipboard Radar

SIGINT and the Pusan Perimeter

Signals from Outer Space

The Diyarbkir Radar

The Government and UFOs

The Origin of U.S.-British Communications
   Intelligence Cooperation (1940--1941)

The U.S. Hunt for Axis Agent Radios

The Yo-Yo Story: An Electronics Analysis Case

Chapter III.    The Chi-Stelle

Chapter IV.    Organization and Operation of the Field Units
      Section A.   Operations in the West
      Section B.   Operations in the East
      Section C.   Operations in the South
      Section D.   Operations in the North

Chapter V.     Cryptanalysis

Chapter VI.    Liaison

Chapter VII.   Critique of the Organization and Operations of the German Air Force Signal Intelligence Service

Appendix:      "Early Warning" by Technical Sergeant Gerd Watkinson, Duty Officer, Meldekopf 1, German Air Force Signal Intelligence Service.

Tab A:           Glossary

DOCID: 3560829 VOLUME 5


Chapter I. The Service in General: Sources of Information Concerning It


Introduction                           1

Objectives                             2

Detailed Successes                 3

Administrative Difficulties        4

Sources of Information  5

1. Introduction~- This volume presents a discussion of  the history, org&n1zation and operations of the German Air Force Signal Intelligence Service from its beginning in 1937 until the German capitulation in 1945.

The outstanding achievement of the German Air Force Signal Intelligence Service was its development of "signal intelligence without cryptanalysis." The exploitation of every radio manifestation, which for the Germans included radar monitoring, the monitoring of beacons, the evaluation of tuning transmissions and chatter, highly efficient direction finding, radio telephone monitoring and traffic analysis, provided valuable strategic and tactical intelligence.

The service was expanded from one officer and twenty civilians in 1937 to thirteen thousand persons in 1945, of which ;sixty-six hundred were in the West, four thousand in the East, and twenty-four hundred in the South.

2. Objectives.. - The lightning advances of the Germans in 1939 had resulted in the German Air Force Signal Intelligence Service placing its main emphasis on radio telephone monitoring and tactical evaluation. During the quiet period after the fall of France, stress was placed on strategic evaluation in order to present a coherent picture of British Air Order of Battle and long range intentions. In addition, small units were located in the Balkans to provide intelligence of Russian deployment and intentions. Strategic evaluation continued throughout the war, but as allied raids were intensified in 1943 tactical evaluation again became important as a means of providing early warning or impending Allied raids. For this purpose an intricate system of reporting centers (Meldekopfe) and a central warning unit (Zentraler Gefechsstand fuer Funkauswetung) were established in 1944. The evaluation of the traffic of tactical air force units operating in conjunction with Allied ground armies was also stressed as the Germans were forced on the defense on all fronts.

3. Detailed successes of signal intelligence. --The steps leading to the success of" the German Air Force Signal Intelligence in their attack on Allied. radio traffic will be treated in later chapters. A summary of that success will be indicated here by briefly sketching the results achieved against Russia, the United States, and Britain.

a. Russia. -- Throughout the course of the war against Russia 85 percent of the Morse ground-to-ground traffic of the Soviet Air Armies, Corps and Divisions and of the supporting ground organizations was deciphered. Ground-to-ground radio traffic (such as fighter control) consisting of simple word encodements was continuously solvable. The air-ground traffic of the Soviet long-range bomber formations, although only partially deciphered, permitted German traffic-analysts to chart Soviet air raids in t1me.to give adequate warning. The great volume of information derived from message contents and from traffic analysis of the structure and functioning of the networks enabled the German Air Force Signal Intelligence Service in the East to present to its intelligence authorities an accurate and current listing of the Soviet Air Force order of battle on the three operational front, and of the deployment of the Russian ground forces to which the Soviet air forces served as an adjunct. Furthermore this information provided immediate and timely warning of air raids, route-tracking of bomber formations, as well as indicated long-range intentions of both Soviet ground and air forces, and provided information of supply and economic conditions.2 Although up until the time of Stalingrad signal intelligence warnings had not been heeded, when the signal intelligence unit on the Southern Front correctly advised that the Russians had assembled 5 air armies in the Stalingrad sector. "sigint was held to be the main source of intelligence."3

b. United States.--The chief success against the United States Air Force was made possible by alert traffic analysis.

Although air-ground systems, Used jointly by the American and British, were read in many cases (e,g. Bomber Code, REKOH, and SYKO), the effectiveness of cryptanalysis was definitely limited.

The Chief of the German Air Force Signal Intelligence Agency. Lt. Col. Friedrich, claimed that he had "no contents from ground-ground radio traffic;"4 and interrogations showed that whatever success was achieved with M 209 was usually too late for exploitation.

Traffic analysis, however, was able to provide A-2 with a comprehensive and continuous picture of the battle order and deployment of the United States Air Force in Britain, later on the continent, and in the Mediterranean. Numerous predictions were also made of long-range air force intentions. Tactically, traffic analysis of "all radio manifestations" (which for the Germans included everything from radio signals to beacons) gave·

2I 70  p 4

3I 41  p 7

4I 70  p 5

immediate and timely warning of American air raids. As a result of· what Friedrich called "the reliance on good encipherment and neglect of supervision of American radio traffic ... the almost continuous radio traffic in the air ... and radio traffic beginning regularly and uniformly, always sent by routine procedure..."5, the Germans were able to reconstruct in the West the organization and strength of the 8th United States Air Force (and its bomber and fighter commands), the 9th Air Force, and the Allied Expeditionary Air Force (consisting of the United States 9th Air Force, the 1st United States Tactical Air Force and the 2nd British Tactical Air Force). The United States 1st Tactical Air Force, Allied Air Transport Units and other air units were successfully monitored. Major long-range operations, such as the invasion and the break-through at Avranches were, with some degree of success, correctly forecast. Tactical monitoring of the United States air support parties "yielded much more information about Allied Army order of battle than did the regular army net works,"6 since the air support parties acted in conjunction with specific ground units.

In the Mediterranean and Middle East the German Air Signals Regiment 352 vas able to recon8t~uct With minute accuracy the dispositions and strength of the Allied Air Force -- the 9thTactical Air Command (one Combat Mapping group, 4 fighter groups, and one medium bomber group). the 57th Medium Bomber Wing, the5th, 47th, 49th, 55th, and 304th Heavy Bomber Wings, the 15th Fighter Command and the Mediterranean Air Transport Service. The accurate reconstruction of Allied order of battle attests to the effectiveness of the German analysts. American A-2 evaluation of German signal intelligence operations directed against the United States 9th Air Force states that the portions of the German discussions "dealing with the operations and activities of the 9th Air Force reveal a full and complete knowledge on the part of the Luftwaffe Signal Intelligence Service...The success of (their) efforts and the degree to which (their)operations had been developed vas an uncomfortable surprise...The information of the enemy was thorough, complete, and accurate in its broad aspects; there were minor discrepancies, inaccuracies, confusion; .... but. in general, it may be said that the Luftwaffe Signal Intelligence Service was a most scientific, professional and able organization, performing a valuable, meticulously complete, and reliable service for the enemy."7 Operational strengths were in the main correctly estimated and the precision with which unit movements were followed is said to be truly impressive.

The success of the German Air Force Signal Intelligence in its analysis of American Air Force traffic was not exploited by the German operational units, which were sluggish in acting upon the information provided them. Friedrich complained that it was not his job to get the windmills (German fighters) airborne. It was up to him merely to give the warnings.

5I  70  p 5

6IF  182  p 83

7IF  177  p 24

In the Mediterranean, according to members of Air Signals Rgt. 352,· "it was a. course of bitter chagrin to the LuftwaffeSignal Intelligence Service that the German Command lacked the resources to translate its realistic intelligence into offensive action."8

c.  Britain.-- Royal Air Force systems produced the greatest amount of' intelligence on air-ground circuits. SYKO, REKOR, Slidex and the Bomber Code were currently solved. Although the RAF 4-figure code was changed in November 1942 and thereafter proved most difficult for the Germans,9 it had been read up to that time. Both on the strategic and tactical level, German Air Force Signal Intelligence achieved notable results on British Air Force traffic. In the West the Germans were able to reconstruct accurately the order of battle, deployment, strength, equipment, and intentions of the Royal Air Force, and through it, of the ground organization.10 In order of battle, the following RAF units were continuously followed throughout the war: The 1st, 3rd. 4th, 5th, 6th, 8th, 9lst, 92nd. 93rd, Bomber Groups; the 100th Group, the 9th, l0th, 11th, 12th, 13th, and 82nd Fighter Groups; the 15th, 16th, 17th, 18th, 19th Reconnaissance Groups of the Coastal Command; and units of the 2nd Tactical Air Force, and of the RAF Transport Command.

On the tactical level the monitoring of RAF VHF and centimeter radar transmission and navigational aids permitted the German Air Force Signal Intelligence Service "to accomplish the following:

(1) To give accurate, long and short interval, early warning of both daylight and night raids of heavy bomber formations;

(2) By continuously tracking heavy bomber formations to present to the fighter defense a lucid picture of the air situation, from the time of take-off to the landing of enemy formations; further,

(3) To interpret the picture of the air situation in such a manner as to predict the enemy's strength in formation, depth of penetration, targets, and deceptive tactics.11

In the Mediterranean area, German Air Force Signal Intelligence was able to chart RAF operations throughout the war. In the first years of the war German Air Force Signal Intelligence service succeeded, by breaking "the most frequently used cryptograhic systems... to read the bulk of the messages intercepted.12 The extensive use of radio communications (occasioned both by the geographical extent of the Mediterranean theater, and an insufficiency of wire communication facilities )13

8IF  185  p 24

9I  70  p 5

10IF  183  p 42

11IF  183  p 2

12IF  185  p 2

13IF  185  p 2

permitted a minutely accurate reconstruction of RAF order of battle, strength, equipment and intentions. German Air Force Signal Intelligence was able to follow RAF operations down to squadron level. - The following units were monitored: the 206th and 225th Reconnaissance Squadrons, the 414th and 416th Night Fighter Squadrons, the 8th Fighter Group of the South African Air Force, the various units of the RAF Desert Air Force (MASAF),elements of the 90th Mediterranean Allied Photo Reconnaissance Wing, the RAF Mediterranean Allied Coastal Air Force (MACAF) and the various components of RAF Middle East, including the RAF Balkan Air Force, RAF Air Headquarters, Greece, Eastern Mediterranean, and Air Transport Command.

4. Administrative Difficulties.--The success of the Air Force analytic effort seems to have been achieved in spite of rather than because of the administration of the organization. Interminable disputes prevented the smooth functioning of the service. One of the issues frequently disputed was whether it was better for the Signal Intelligence Agency to be subordinated to the Chief Signal Officer General Nachrichten Fuehrer, abb. Gen. Nafue), or to the A-2. Another subject of controversy was the separation of administrative from operational control, set out at least on paper, between the Senior Signal Intelligence Officer (Hoeherer Kommandeur der Funkaufklaerung, abb. Hoe Kmdr d Funkaufklrg) and the Signal Intelligence Agency. There were arguments over the exercise of the various types of control (administrative, tactical-operational, strategic-operational, etc.) over the units in the field, that is the Air Signal Regiments and the Air Signal Battalions (Luftnachrichten Regiments, abb. LN Regt, and Luftnachrichten Abteilungen, abb. LN Abt).The latter disputes involved the rival claims for the control of the Air Force Signal Intelligence, the centralized Signal Intelligence Agency, the decentralized local Air Forces (Luftflotten), the Senior Signal Intelligence Officer, and in the latter stages of the war, the Chief of the Air Raid Warning Service for Germany (Funkaufklaerungsfuehrer Reich, " bb. FAF).

These claims, when they were settled at all, were resolved by compromise and appeasement. In general, the Signal Intelligence Service was subordinated to the Chief Signal Officer and not to the A-2, although the latter was the chief consumer of the intelligence product.

The control over the field regiments and battalions maybe outlined as follows:

a. Administrative or service matters: Control was exercised by the Senior Air Signal Intelligence Officer (Hoe Kmdr d Lu FA) to whom the Commanders of the Air Signal Regiments and Battalions were subordinated.

b. Tactical matters (strategic movements and deployment): Control was exercised by the Signal Officer of the local air force (Luftflotte) to vhioh the field unit was attached.

c. Operational matters: Control was exercised by the Signal Intelligence Agency (LE Abt-350 in the 1944 reorganization) of the Air Force (Oberbefehlshaber der luftwaffe, abb.Ob d L)


5. Sources of Information.. - Several sources of informationwere used for this volume:

 a. The TICOM interrogations of prisoners. (The I Reports)

 b. A 13-volume report entitled "The Signal Intelligence Service of the German Luftwaffe" compiled by Col. J. Q. Seabourne. chief of the Air Technical Intelligence Team of the USAAF. (IF 175 through IF 187).

 c. Report of the British Air Ministry (A.D.I.(K)),14 entitled" German Air Force Signals Intelligence in the War."

 d. German documents captured by TICOM teams conslst1ng of minutes of Signal Intelligence meetings, reports, etc. including filmed excerpts from-the Supplementary Volume B to War Diary 2 (Division 1) (Anlagenband B. Zu Kriegstagebuch II).

  (1) TICOM, through its interrogations of prisoners obtained a working picture of the German Air Force Signal Intelligence service. Traffic analysts and cryptanalysts active in the Chi Stelle and in the various field units explained the details of their operations. Chief among these were Lt. Col. Friedrich, head of the 3rd Division of the Office of the Chief Signal Officer (Gen. Nafue III) which dealt with signal intelligence, and at the same time Chief or Air Signal Battal10n 350 (LN Abt. 350, The Signal Intelligence Agency). Specialist (Regierungsrat) Dr. Voegele, Chief Cryptanalyst of the German Air Force Signal Intelligence Service and specialist on Anglo-American systems, I118de a number of reports. Lt. Ludwig, chief evaluator on the western front; Major Felchtner, Commanding Officer of Air Signals Regiment 352., which operated on the Mediterranean front; Captains Herold and Scheidl, 1st Lt. Werther and Chlubekj ~nd Lieutenants. Smolin and Rasch, all active all the Eastern front against Russia. and Major Oeljeschlaeger, of Friedrichts staff. provided reports of thE>ir respective activities" .

  (2) The 13-volume report prepared under the direction of Col. J. G. Seabourne, Chief of the Air



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