Signals intelligence in modern history

Signals intelligence in modern history

::"This article is a subset article of the article Signals intelligence, which addresses the unifying conceptual and technical factors and common technologies in this intelligence discipline. This article deals with signals intelligence in the context of modern history. See Signals intelligence by alliances, nations and industries for the organization of signals intelligence activities. For a complete hierarchical list of articles, see the intelligence cycle management hierarchy."

SIGINT is a contraction of SIGnals INTelligence. Before the development of radar and other electronics techniques, signals intelligence and communications intelligence (COMINT) were essentially synonymous. Sir Francis Walsingham ran a postal interception bureau with some cryptanalytic capability during the reign of Elizabeth I, but the technology was only slightly less advanced than men with shotguns, during World War I, who jammed pigeon communications and intercepted the messages carried.

Signals intelligence became far more central to military (and to some extent diplomatic) intelligence generally with the mechanization of armies, development of blitzkrieg tactics, use of submarine and commerce raiders warfare, and the development of practicable radio communications. Even Measurement and Signature Intelligence (MASINT) preceded electronic intelligence (ELINT), with sound- and flash-ranging techniques for artillery location. SIGINT is the analysis of intentional signals for both communications and non-communications (e.g., radar) systems, while MASINT is the analysis of unintentional information, including, but not limited to, the electromagnetic signals that are the main interest in SIGINT.

World War I

Radio communications were fairly new at this time. At the strategic level, nations gained access to commercial cable traffic. Tactically, wired telephones were in wide use, and techniques of intercepting them through ground returns were developed. These intercept techniques have had a resurgence in later wars, where radio was less available or impractical. On the declaration of war, one of Britain's first act was to cut German undersea cables, forcing them to use radio, which the British could intercept. The practice of destroying more secure wired communications, to improve the intelligence take, has been a regular practice since then. While one side may be able to jam the other's radio communications, the intelligence value of poorly secured radio may be so valuable that there is a deliberate decision not to interfere with enemy transmissions.

Russia, when preparing for the Russo-Japanese War in 1904, had established a tradition of poor communications that would last well after the fall of the Romanovs. The success of this and related salvage and rescue work persuaded the Russian Navy to install wireless sets on many of its ships. In early 1904, the Russian fleet prepared for war with Japan. The British almost immediately began to intercept their communications, with the complaint “An intelligence report on signals intercepted by HMS Diana at Suez shows that the rate of working was extremely slow by British standards, while the Royal Navy interpreters were particularly critical of the poor standard of grammar and spelling among the Russian operators.”cite web
last = Lee
first = Bartholomew
title = Radio Spies -- Episodes in the Ether Wars
url =
accessdate = 2007-10-08 |format=PDF
] After such an embarrassing start, the great Russian mathematical tradition, and probably the national passion for chess, has made Russia, regardless of other shortages, a great innovator in communications and cryptology.

Failure to properly protect its communications fatally compromised the Russian Army in its advance early in World War I and led to their disastrous defeat by the Germans under Ludendorff and Hindenburg at the Battle of Tannenberg. Similarly, the interception and decryption of the Zimmerman telegram was an important factor in the US decision to enter the War.

Radio researchers at the British Marconi company realized that strange signals they were receiving were German naval communications, and brought them to the Admiralty. Soon, the British were operating a network of listening posts called "Y Stations", with Admiralty Room 40 doing the traffic analysis and cryptanalysis Lee p. 10-12] . In World War II, the British referred to their traffic analysis function as the "Y service".

In contrast, battles have been lost, or not fought, when senior commanders asked the traffic analysts and direction finders, the wrong question. In World War I, British Admiral John Jellicoe, 1st Earl Jellicoe, knew a little too much detail about SIGINT without fully understanding it. He asked the analysts where call sign "DK" was located cite book
last = Kahn
first = David
authorlink = David Kahn
title = The Codebreakers - The Story of Secret Writing
publisher = Scribners
url =
date = 1996
isbn = 0684831309
] . DK was the headquarters of the German High Seas Fleet. The analysts answered his question precisely, telling him that it was "in the Jade River". Unfortunately, Jellicoe did not know that the High Seas Fleet commander used a different identifier when at sea. Jellicoe assumed the German fleet was also in the Jade River, and missed an opportunity for a decisive battle. When he found out the true situation, he lost faith in SIGINT, not accepting that it was his own error.

Jellicoe's faith in cryptographic intelligence was also shaken by a decrypted report that placed the German cruiser Regensburg near him, during the Battle of Jutland. It turned out that the navigator on the Ravensburg was off by convert|10|mi|km|0 in his position calculation. During Jutland, there was limited use of direction finding on fleet vessels, but most information came from shore stations.

France had significant signals intelligence in World War I. While the key intelligence achievement in blunting the German drive on Paris in June 1918 was the cryptanalysis of Georges Painvin, had French intercept personnel not captured the message in the ADFGVX cipher, there would have been nothing to cryptanalyze.

Between the World Wars

There was substantial SIGINT work between the World Wars, although the secrecy surrounding it was extreme. While it was primarily COMINT, ELINT emerged with the development of radar.

Both sides developed direction-finding (DF) and communications interception stations during the war, although those programs often began with naval search & rescue.


Canada's first signals intelligence intercept site, Special Wireless Station #1, was built in 1939, in Ottawa. "#2 SWS was located at Grande Prairie, Alberta and #3 SWS at Victoria B.C. Victoria also had a remote High Frequency Direction Finding (HF/DF) site in Nanaimo approximately convert|60|mi|km|0 to the northwest." [cite web
last = Troyanek
first = Jim
title = The "Special" Wireless Stations
url =
accessdate = 2007-10-08
] 1 Canadian Special Wireless Group (1CSWG) deployed to Australia in January 1945.


By the mid-twenties, German Military Intelligence Abwehr was intercepting and cryptanalyzing diplomatic traffic. Under Hermann Goering, the Nazi Research Bureau ("Forschungsamt" or “FA”) had units for intercepting domestic and international communications. The FA was penetrated by a French spy after 193????, but the traffic grew to a point that it could not easily be forwarded. In addition to intercept stations in Germany, the FA established an intercept station in Berne, Switzerland. It penetrated most cryptosystems other than the UK and US. Lee]

German Condor Legion personnel in the Spanish Civil War ran COMINT against their opponents.

United Kingdom

After the First World War, British Army and Navy COMINT merged and formed a new organization, reporting to the Admiralty, called the "Government Code and Cypher School", with Alastair Denniston as its first head.

While it was operational in 1919, it was realized most of its current work was diplomatic, so it was transferred to report to the Foreign Office. Both GCCS and the Secret Intelligence Service reported to Hugh Sinclair, in London. In May 1927, Prime Minister Stanley Baldwin made public some GCCS solutions of Soviet intercepted message, causing a massive Soviet cryptographic change.

By 1940, GCCS was working on the diplomatic codes and ciphers of 26 countries, tackling over 150 diplomatic cryptosystems [David Alvarez, GC&CS and American Diplomatic Cryptanalysis] .

United States

Naval direction finding and message interception

US communications monitoring of naval signals started in 1918, and continued, but was used first as an aid to naval and merchant navigation. In October 1918, just before the end of the war, the US Navy installed its first DF installation at its station at Bar Harbor, Maine, soon joined by five other Atlantic coast stations, and then a second group of 14 installations. cite web
author = Clancey, Patrick
title = Battle of the Atlantic, Volume I. Allied Communications Intelligence, December 1942 to May 1945 [SRH-005]
work = HyperWar: A Hypertext History of the Second World War
publisher = HyperWar Foundation
url =
accessdate = 2007-10-15
] . These stations, after the end of World War II, were not used immediately for intelligence. While there were 52 Navy MF DF stations in 1924, most of them had deteriorated. The Navy transferred, in July 1941, the remaining stations to the US Coast Guard.

As tension with the Japanese grew, the COMINT situation was being reviewed. In the early 1930s, the Navy started implementing HF/DF. Eleven locations were planned, primarily on the Atlantic Coast, and beginning with Bar Harbor, Maine, early 1936. The first operational intercept came from what would later be called Station CAST, at Cavite in the Philippines. There were still technical problems, a development program started, and the first advanced station created at Winter Harbor. In July 1939, the function turned from training and R&D to operations, and the Navy officially established a Strategic Tracking Organization under a Direction Finder Policy.

By December 1940, the Navy's communication organization, OP-20-G, had used HF/DF on German surface vessels and submarines. Training continued and cooperation with the British began. In April 1941, the British gave the US Navy a sample of their best HF/DF set from Marconi.

All remaining navigational DF stations were transferred to the Coast Guard in May 1941, and the Navy concentrated its efforts on COMINT, reporting to OP-20-G under Commander Laurance F. Safford. By December 1941, the Navy established a strategic HF/DF and intercept station, with Atlantic, Pacific and West Coast net control stations managing 20 sites. Increasingly, new site selection emphasized COMINT value over HF/DF. The prototype intercept station had been in Maine, initially in Bar Harbor but relocated to Winter Harbor in 1935. It principally intercepted European traffic to Tokyo, but also had a section intercepting Soviet traffic. Intercept reorganization came during the first week of September, with Atlantic stations reemphasizing HF/DF, and interception at Jupiter, Florida and Cheltenham, MD. The Cheltenham station was replaced by Chatham MA as the primary intercept station. HyperwarSHR-005]

hip platforms

Beginning in 1937, US naval ships started intercepting communications, beginning with the destroyer USS Hatfield (D-231). It anchored at La Rochelle-Paris and started operating, but lack of intercept training quickly became evident. The Director of Naval Communications established policies and procedures; it should be noted that COMINT reported Communications, not Intelligence.

The European squadron, 40-T, with USS Raleigh (CL-7) as flagship, originally was assigned to evacuate civilians from the Spanish Civil War, but a secondary COMINT duty became evident, with a unit established on the USS Omaha (CL-4) in 1938, soon designated as Station F, intercepting German, and Italian traffic, later in the Mediterranean.

Station F moved to the new flagship, USS Trenton (CL 11) in June 1939. They noted significant communications changes two days before the German invasion of Poland, and the intelligence significance was noted and forwarded to Washington. In 1939, the Atlantic was the priority, with a very short belief Japan was not a threat. In 1940, formal liaison began with the British, under the terms of a highly secret policy accepted in 1937. The Special Naval Observer in London was the point of contact, and formal COMINT exchange began in November 1940.

Station F, still on ships, concentrated on Italian traffic in 1940. OP-20-G began cryptanalytic work in July 1940. OP-20-G was acutely aware of British ship losses in the Battle of the Atlantic. Focus remained on the Atlantic, with Agnes Driscoll, the chief cryptanalyst under LT Lee W. Parke, worked on Italian systems; German system remained secure.

Increased pace in 1941

In 1941, the sensitivity of COMINT increased when the US gave Britain a PURPLE machine. The British did not reciprocate with full ULTRA information on ENIGMA, but the US received paper information on ULTRA as well as current British HF/DF procedures.

Operational priority increased when Winter Harbor and Amagansett received teletypes for faster relay of intercepts to the analysts in Washington. While the emphasis was now on Japanese traffic, other traffic of interest was still studied.

COMINT against the inter-war Japanese

COMINT of Japanese traffic proved invaluable to the Allies at the Washington Naval Conference in 1921, through cryptanalysis by Herbert Yardley. Then-Secretary of War Henry L. Stimson closed the US Cipher Bureau with the words "Gentlemen do not read each other's mail." Luckily for US COMINT, the Army offered a home to William Friedman after Stimson closed the Yardley operation.

Friedman's team had four analysts that would become bright figures in American cryptology: Solomon Kullback, Frank Rowlett, and Abraham Sinkov. Kahn's memorable comment "If Yardley was the star of American cryptology, Friedman was the Sun" remains apt. They developed largely manual cylindrical and strip ciphers, but, as a result of Friedman's advances in cryptanalysis, machine ciphers became a priority, such as the M134, also known as the SIGABA. While the SIGABA was a rotor machine like the German Enigma, it was never known to be cracked. It was replaced by electronic encryption devices.

SIS, in contrast with Yardley's dependence on cable companies, set up its own radio intercept organization. Eventually, the training and intercept functions were separated for both administrative and security reasons, when, a centralized signals intelligence unit, the 2d Signal Service Company, was set up at Fort Monmouth on 1 January 1939 to control all Signal Corps personnel at the permanent monitoring installations. In this period, SIS paid less attention to tactical SIGINT.

World War II

A true world war, SIGINT still tended to be separate in the various theaters. Communications security, on the part of the Allies, was more centralized. Given that there were three major Axis powers, each primarily operating in a subset of the theaters, it is convenient to look at SIGINT from a primarily theater standpoint. From the Allied perspective, the critical theater-level perspectives were the Ultra SIGINT against the Germans in the European theater (including the Battle of the Atlantic, the Mediterranean Theater, and MAGIC against the Japanese in the Pacific Theater and the China-Burma-India theater. Germany enjoyed some SIGINT success against the Allies, especially with the Merchant Code and, early in the war, reading American attaché traffic. Japan was the least effective of the major powers in SIGINT. In addition to the official Allies and Axis battle of signals, there was a growing interest in Soviet espionage communications, which continued after the war.

British strategic stations were located at places including Darwin in Australia, and a Russian site. Major postwar stations include Menwith Hill and Cyprus.

Allied European Theater

The use of SIGINT had even greater implications during World War II. The combined effort of intercepts and cryptanalysis for the whole of the British forces in World War II came under the code name "Ultra" managed from Government Code and Cypher School (Bletchley Park).

(British) Royal Navy

Early on, Admiralty dismissal of SIGINT information (also traffic analysis in this instance) contributed to the loss of HMS "Glorious" in 1940.

Perhaps the most important role SIGINT played for the Royal Navy, and the merchant ships it protected, was in the Battle of the Atlantic. By comparison with the close and garrulous radio communication between the U-boat submarine high command, BdU, and German submarines in the Atlantic, US submarines in the Pacific enjoyed the freedom of fish. While ULTRA cryptanalysis certainly played a role in dealing with German submarines, HF/DF and traffic analysis were complementary.

It is unclear why the German submarine command believed that frequent radio communications were not a hazard to their boats, although they seemed confident in the security of their Enigma ciphers, both in the initial three-rotor and subsequent four-rotor versions (known as Triton to the Germans and Shark to the Allies). There was an apparent, mutually reinforcing belief that wolf pack attacks by groups of submarines were much more deadly than individual operations, and confidence the communications were secure. Arguably, the Germans underestimated HF/DF even more than they did British cryptanalysis [Citation
last = Barratt
first = John
journal = Military History
title = Enigma and Ultra - the Cypher War
id = Barratt 2002
year = 2002
url =
accessdate =
] . Apparently, the Germans did not realize that the Allies were not limited to slow, manually operated direction finders, and also underestimated the number of direction finders at sea.

Battle of Britain

ELINT and electronic warfare became critical parts of the Battle of Britain. R.V. Jones was a key scientist in the "Battle of the Beams", defeating Nazi radio navigation systems (e.g., Knickebein). While the ULTRA COMINT successes against the Germans were not declassified until 1975, Winston Churchill paid homage to electronic warfare, and its companion ELINT, in his series on the Second World War: "During the human struggle between the British and the German Air Forces, between pilot and pilot, between AAA batteries and aircraft, between ruthless bombing and fortitude of the British people, another conflict was going on, step by step, month by month. This was a secret war, whose battles were lost or won unknown to the public, and only with difficulty comprehended, even now, to those outside the small scientific circles concerned. Unless British science had proven superior to German, and unless its strange, sinister resources had been brought to bear in the struggle for survival, we might well have been defeated, and defeated, destroyed." [cite book
last = Churchill
first = Winston
authorlink = Winston Churchill
title = The Second World War, Volume 2: Their Finest Hour
publisher = Penguin Books Ltd
date = 2005
isbn = 0141441739
] . In modern terms, of course, MASINT was as important as SIGINT in defeating Nazi navigational systems, with radar control of the defenses a key part of the Battle of Britain.

French Resistance and Free French

France consolidated a number of general intelligence and SIGINT units in World War II, producing the wartime Directorate of Studies and Research (DGER) by November 1944. As the Cold War heated, France was concerned with the presence of Communist networks among these units, so, in 1946, created the External Documentation and Counterespionage Service (SDECE) subordinated to the prime minister.citation
first = Pike
last = John
title = DGSE - General Directorate for External Security (Direction Generale de la Securite Exterieure)
url =
accessdate = 2007-10-06

Efforts at US coordination during World War II

During the Second World War, the US Army and US Navy ran independent SIGINT organizations, with limited coordination, first on a pure personal basis, and then through committees. Perhaps the strongest outside effect, prior to and during WWII, was the United States Department of State and the White House, the only consumers of intelligence outside the military, especially since both the Army and Navy wanted to have the prestige of providing them with diplomatic COMINT. Note that while the Office of Strategic Services was a fairly autonomous WWII agency, it still, technically, reported to the Joint Chiefs of Staff and received COMINT through military channels. citation
title = The Origins of the National Security Agency, 1940-1952
author = Thomas L. Burns
publisher = National Security Agency
url =
year = 1990

During the war, the military departments became concerned with the creation of new cryptanalytic units in the US government, including the Federal Bureau of Investigation (FBI), Federal Communications Commission (FCC) and Department of State. The military finally formalized the sharing of targets in 1944, but that did not cover the non-military organizations. They established a Joint Army-Navy Radio Intelligence Coordinating Committee, which soon changed its name to the Joint Army-Navy Communications Intelligence Coordinating Committee.

US Army

After the Normandy landings, Army SIGINT units accompanied major units, with traffic analysis as or more important than the tightly compartmented cryptanalytic information. Bradley's Army Group, created on August 1, 1944, had SIGINT including access to ULTRA. Patton's subordinate Third Army had a double-sized Signal Radio Intelligence Company attached to his headquarters, and two regular companies were assigned to the XV and VIII Corps.

The 3250th Signal Radio Intelligence Company, attached to V Corps, moved 10 times in June and July 1944, and suffered nearly 20 percent casualties during the Battle of the Bulge, including four killed in action. citation
first = Browne
last = Joseph
journal = Army Communicator
title = Radio-traffic analysis' contributions
date = 2006
url =
accessdate = 2007-10-15

US Navy

In World War II anti-submarine warfare (ASW), shore or ship-based SIGINT often vectored long-range patrol aircraft to U-boats, which they might detect visually or by airborne radar if the submarine was surfaced, or by early sonobuoys used from 1944 on, which could cue dropping depth charges or very early homing torpedoes. The Army demonstrated feasibility of the AN/CRT-1 sonobuoy, and, by 1944, the Navy had ordered almost 60,000 [cite web
last = Cote
first = Owen R. Jr.
title = The Third Battle: Innovation in the U.S. Navy's Silent Cold War Struggle with Soviet Submarines
work =
publisher = MIT Security Studies Program
date = March 2000
url =
id = Cote 200
accessdate = 2000-10-16

A daring US Navy feat that received very mixed reviews was the capture of the Unterseeboot 505 (U-505) by CAPT Daniel Gallery's escort carrier group. While useful cryptomaterial was taken from the boat, Gallery and his immediate chain of command were unaware of the ULTRA successes against German submarines. There was considerable concern at Bletchley Park that if the Germans realized a U-boat, and presumably its Enigma had been captured, the Germans might change cryptosystems. The notoriously hot-tempered Chief of Naval Operations, FADM Ernest J. King considered court-martialing Gallery, but relented and authorized the award of a Distinguished Service Medal with a classified citation.

Appropriately, however, the first US sailor, LT Albert David, to go down the hatch of the submarine, which might have scuttling charges about to detonate or have water rushing in, received the Medal of Honor. The two sailors behind him received the Navy Cross.

Axis European Theater

The entire Nazi system suffered from Hitler's deliberate fragmenting of authority, with Party, State, and military organizations competing for power, with only Hitler really pulling the strings. Hermann Goering also sought power for its own sake, but was much less effective as the war went on and he became more focused on personal status and pleasure.

German air intelligence, during the Battle of Britain, suffered from the structural problem that subordinated intelligence to operations. Operations officers often made conclusions that best fit their plans, rather than fitting conclusions to informationcite web
last = Lund
first = Earle
authorlink =
coauthors =
title = The Battle of Britain: A German Perspective; Addendum, Luftwaffe Air Intelligence During the Battle of Britain
url =
accessdate = 2007-10-06
] .

In contrast, British air intelligence was systematic, from the highest-level, most sensitive ULTRA to significant intelligence product from traffic analysis and cryptanalysis of low-level systems. Fortunately for the British, German aircraft communications discipline was poor, and the Germans rarely changed call signs, allowing the British to draw accurate inferences about the air order of battle.

A 1939 German intelligence study Earle pp 30-32] discounted British radar and ground-controlled interception, and believed the only serious defenses were in the London area. Goering was not receptive to dissenting views that key targets were out of bomber range, and significantly out of the range of escort fighters.

Allied Pacific Theaters

Several theaters were involved in this part of World War II: CINCPAC/CINCPOA, CINCSWPAC, CINCCBI.

Allied cooperation in the Pacific Theater included the joint RAN/USN Fleet Radio Unit, Melbourne (FRUMEL), and the Central Bureau which was attached to the HQ of the Allied Commander of the South-West Pacific area.

Australian Army

After consultations between Australian and US signal and communications senior staff, MacArthur ordered Central Bureau to be created, partially to avoid his being dependent on Navy SIGINTCitation
title = Central Bureau in Australia during World War II: A Research and Control Centre for the Interception and cryptanalyzing of Japanese intelligence
author = Dunn, Peter
date = 9 April 2000
url =
accessdate = 2006-10-16
] . Central Bureau was made up of::*The intelligence section of the former No. 4 Australian Special Wireless Section:*Australian Military personnel:*RAAF personnel:*US Army intelligence personnel who had escaped from the Philippines:*US Army intelligence personnel from USA (6 officers and 8 men of the 837 Signals Service Detachment):*British intelligence staff from Singapore

At first, Central Bureau was made up of 50% American, 25% Australian Army and 25% Royal Australian Air Force (RAAF) personnel, but additional Australian staff joined. In addition, RAAF operators, trained in Townville in intercepting Japanese telegraphic katakana were integrated into the new Central Bureau. Other components of Central Bureau included::*the Geographical Section which produced maps and geographical data about the SWPA:*the Allied Translator and Interpreter Section (ATIS) which interpreted millions of captured documents, intercepted messages and interrogated thousands of Japanese POW's:*the Australian Coast Watching Service:*a POW interrogation center.

Central Bureau broke into two significant Japanese Army cryptosystems in mid-1943.

Australian Navy

FRUMEL was the joint US-Australian naval SIGINT unit. Commander, later Captain, Eric Nave did not stay long with FRUMEL, which was put under U.S. Navy control in mid-1942. He was sent to Central Bureau in mid-1942, but it has been suggested he dealt only with lesser Japanese systems, although he had both Japanese language skill and experience with their cryptosystems. The major systems were the target of US Col. Abraham Sinkov. [Citation
last = Dunn
first = Peter
author2-link =
title = RAN/USN Fleet Radio Unit, Melbourne - FRUMEL
date = 14 November 2000
url =
accessdate = 2006-10-16

Until Central Bureau received replacement data processing equipment for that which was lost in the Philippines, as of January 1942, U.S. Navy stations in Hawaii (Hypo), Corregidor (Cast) and OP-20-G (Washington) decrypted Japanese traffic well before the U.S. Army or Central Bureau in Australia. Cast, of course, closed with the evacuation of SIGINT personnel from the Philippines.

US Navy

US strategic stations targeted against Japanese sources included Station HYPO in Hawaii, Station CAST in the Philippines, station BAKER on Guam, and other locations including Puget Sound, and Bainbridge Island.

US COMINT recognized the growing threat before the Pearl Harbor attack, but a series of errors, as well as priorities that were incorrect in hindsight, prevented any operational preparation against the attack. Nevertheless, that attack gave much higher priority to COMINT, both in Washington DC and at the Pacific Fleet Headquarters in Honolulu. Organizational tuning corrected many prewar competitions between the Army and Navy.

Perhaps most dramatically, intercepts of Japanese naval communications cite web
last = National Security Agency
authorlink = National Security Agency
title = Battle of Midway
url =
id = NSA Midway
accessdate = 2007-10-02
] yielded information that gave Admiral Nimitz the upper hand in the ambush that resulted in the Japanese Navy's defeat at the Battle of Midway, six months after the Pearl Harbor attack.

US Army

The US Army had shared, with the Navy, the Purple attack on Japanese diplomatic cryptosystems. Many histories assume Purple included Japanese military cryptanalysis, but those were separate projects, although generally under the same organizations.

After creation of the Army Signal Security Agency, the cryptographic school at Vint Hill Farms, Warrenton, VA, trained analysts. As a real-world training exercise, the new analysts first solved the message center identifier system for the Japanese Army. Until Japanese Army cryptosystems were broken later in 1943, the order of battle and movement information on the Japanese came purely from direction finding and traffic analysis.

Traffic analysts began tracking Japanese units in near real time. A critical result was the identification of the movement, by sea, of two Japanese infantry divisions from Shanghai to New Guinea. Their convoy was intercepted by US submarines, causing almost complete destruction of these units. Browne]

Army units in the Pacific included the US 978th Signal Company. based at the Allied Intelligence Bureau's secret "Camp X", near Beaudesert south of Brisbane in southern Queensland. [cite web
first = Peter
last = Dunn
title = 978th Signal Service Company Based at Camp Tabragalba, near Beaudesert, QLB during World War II
date = 2003
url =
accessdate = 2007-10-05
] . This unit was a key part of operations behind Japanese lines, including communicating with guerillas and the Coastwatcher organization. It also sent radio operators to the guerillas, and then moved with the forces invading the Philippines.

US Army Air Force

Even as the planes burned at Clark Field, hours after the Pearl Harbor attack, LT Howard Brown, of the 2nd Signal Service Company in Manila, ordered the unit to change its intercept targeting from Japanese diplomatic to air force communications. The unit soon was analyzing Japanese tactical networks and developing order of battle intelligence. He moved from Manila to Corregidor on Christmas Eve.

They learned the Japanese air-to-ground network was Sama, Hainan Island, with one station in Indo-China, one station near Hong Kong, and the other 12 unlocated.Browne] Two Japanese naval stations were in the Army net, and it handled both operations and ferrying of aircraft for staging new operations. Traffic analysis of still-encrypted traffic helped MacArthur predict Japanese moves as the Fil-American forces retreated in Bataan.

Evacuated, as were most SIGINT people, from the Philippines, Brown, helped build the Australian-American intercept station, and 126th Radio Intelligence Company, at Townsville, Queensland. He later trained the Air Force SIGINT staff. US Air Force Far East, and its subordinate 5th Air Force, took control of the 126th in June 1943. The 126th was eventually placed under operational control of U.S. Air Force Far East in June 1943 to support 5th Air Force. Interception and traffic analysis from the company supported the attack into Dutch New Guinea in 1944.

The US began airborne ELINT against Japanese radar in the Aleutians, using a modified B-24 aircraft in January 1943. ELINT was much less significant in the early Pacific War than in the European Theater, probably because strategic bombing using electronic navigation aids was not a critical issue.

US Marine Corps

In 1943, the US Marines organized the 2nd Radio Research Platoon, which was the original unit in a chain of tactical SIGINT units that also made strategic contributionscite web
last = USMC, 1st Radio Battalion, Vietnam Veterans
title = History - 1st Radio Battalion 1943 - 1973
url =
accessdate = 2007-10-06
] .

Japanese SIGINT

Japan had been fighting in China and Manchuria since the 1930s. They were overconfident in their communications security.


In September 1940, the Japanese moved into the Haiphong area of French Indochina, claiming they wanted to disrupt supply lines to their war in China. In June 1941, they expanded their occupation to all of the colony, to which the US responded with embargoes that the Japanese regarded as a "casus belli" for the Battle of Pearl Harbor. US Army and Navy cryptanalysts were able to follow events, initially through their penetration of the RED cryptomachine, and then the PURPLE system, introduced in 1939 and broken in 1940.

Principally to track shipping, the US monitored Japanese, and eventually French colonial administration, traffic, through WWII. In general, the area was not of strong operational interest to the Allies, except for planning submarine attacks on shipping, and occasional air raids on transportation infrastructure. On the strategic level, however, the US began to learn more about the resistance groups in Indochina. These groups, especially the Viet Minh, fought the Japanese, but would later fight the French administration, and eventually the Republic of Vietnam (RVN; South Vietnam).

In March 1945, the Japanese, through their own COMINT, were alerted of a potential French coup against the Japanese occupation. Within 48 hours, all the French administrators and troops were captured, except for about 4,000 troops who fled into China. citation
chapter = Prelude: Indochina Before 1950
title = Spartans in Darkness: American SIGINT and the Indochina War, 1945-1975
first1 = Robert J. | last1 =Hanyok
publisher = Center for Cryptologic History, National Security Agency
year = 2002
url =

September 1945 found an emboldened Viet Minh, under Ho Chi Minh and assisted by a US OSS team under MAJ Archimedes Patti, declare the independence of the Democratic Republic of Vietnam (DRV; North Vietnam).cite book
title = Why Vietnam? Prelude to America's Albatross
author = Patti, Archimedes
publisher = University of California Press
year = 1982
] The Allies, however, did not recognize Ho's government, staying loyal to the French.

While the French claimed Ho's movement was Communist, US State Department analytic reports in 1947 and 1948, written from all-source intelligence including COMINT, gave no indication that the Vietnamese Communist Party was controlled by Moscow.

Western counterespionage

From 1943 to 1980, the VENONA project, principally a US activity with support from Australia and the UK, recovered information, some tantalizingly only in part, from Soviet espionage traffic. While the Soviets had originally used theoretically unbreakable one-time pads for the traffic, some of their operations violated communications security rules and reused some of the pads. This reuse caused the vulnerability that was exploited. VENONA gave substantial information on the scope of Soviet espionage against the West, but critics claim some messages have been interpreted incorrectly, or are even false. Part of the problem is that certain persons, even in the encrypted traffic, were identified only by code names such as "Quantum". Quantum was a source on US nuclear weapons, and is often considered to be Julius Rosenberg. The name, however, could refer to any of a number of spies.

Aftermath of World War II and the 1950s

After the end of World War II, all the Western allies began a rapid drawdown. At the end of WWII, the US still had a COMINT organization split between the Army and Navy. citation
chapter = Chapter 1 - Le Grand Nombre Des Rues Sans Joie: [Deleted] and the Franco-Vietnamese War, 1950-1954
title = Spartans in Darkness: American SIGINT and the Indochina War, 1945-1975
first1 = Robert J. | last1 =Hanyok
publisher = Center for Cryptologic History, National Security Agency
year = 2002
url =
] A 1946 plan listed Russia, China, and a [redacted] country as high-priority targets.

Each service ran independent agreements with foreign counterparts, some of which, especially the British, had already formed a central communications intelligence organization (e.g., the Government Code and Cypher School at Bletchley Park, now the Government Communications Headquarters). Lack of centralization bothered these allies. The vital British-US cooperation was, at this point, one of the strongest incentives to the US Army and Navy to form a centralized organization.

US movement to centralization in SIGINT

The military serves formed a "Joint Operating Plan" to cover 1946-1949, but this had its disadvantages. The situation became a good deal more complex with the passage of the National Security Act of 1947, which created a separate Air Force and Central Intelligence Agency, as well as unifying the military services under a Secretary of Defense. While the CIA remained primarily a consumer, the Air Force wanted its own SIGINT organization, responsive to its tactical and strategic needs, just as the Army and Navy often placed their needs beyond that of national intelligence. The Army Security Agency (ASA) had shared the national COMINT mission with the Navy's Communications Supplementary Activity (COMMSUPACT) - which became the Naval Security Group in June 1950. During and after World War II, a portion of Army COMINT assets was dedicated to support of the U.S. Army Air Corps, and, when the independent Air Force was created in 1947, these cryptologic assets were resubordinated to the new organization as the Air Force Security Service (AFSS).

Secretary of Defense James Forrestal rejected the early service COMINT unification plans. The Department of State objected to the next draft, which put the Central Intelligence Group/Central Intelligence Agency in charge of national COMINT. On 20 May 1949, Secretary of Defense Louis Johnson created the Armed Forces Security Agency.

To centralize common services, the Armed Forces Security Agency (AFSA) as a national organization. AFSA, was formed by secret executive order in 1948. Still, until NSA was formed in 1952, AFSA did not have the authority for central control of individual service COMINT and COMSEC. Policy direction of COMINT came from the U.S. Communications Intelligence Board (USCIB) which, in April 1949, requested $22 million in funds, including 1,410 additional civilian employees, to expand the COMINT effort.

Pacific COMINT targeting prior to the Korean War

For the Pacific, the USCIB targeted China, and Russia in both the European and Pacific theaters, but Korea was a low-priority target: On its second-tier priority list were items of "high importance"; for the month prior to the war, Japan and Korea were item number 15 on the second list, but this did not focus on Korea itself. The specific requirements were "Soviet activities in North Korea", "North Korean-Chinese Communist Relations", and "North Korean-South Korean relations, including activities of armed units in border areas." cite web
last =Hatch
first = David A.
coauthors = Robert Louis Benson
title = The Korean War: The SIGINT Background
publisher = National Security Agency
url =
accessdate = 2007-10-07

trategic SIGINT targeting of the USSR

In the fifties, only aircraft platforms could obtain SIGINT over the USSR. A Soviet source pointed out that aircraft were of limited usefulness, due to being vulnerable to fighters and antiaircraft weapons. (Translator's estimate: in the period 1950-1969, about 15 US and NATO reconnaissance aircraft were shot down over the USSR, China, the GDR and Cuba). The US, therefore, undertook the WS-117L reconnaissance satellite project, approved by President Dwight D. Eisenhower in 1954, within which was a signal intercept subsystem under Project PIONEER FERRET. citation
title = American Geosynchronous SIGINT Satellites
url =
first1 = A. | last1 = Andronov
journal = Zarubezhnoye voyennoye obozreniye
language = Russian
year = 1993
editor = Thomson, Allen (translator)
] By 1959, WS-117L had split into three programs: citation
url =
title = Chapter V, Space Systems
] :#Discoverer, the unclassified name for the CORONA IMINT satellite:#Satellite and Missile Observation System (SAMOS)(IMINT):#Missile Defense Alarm System (MIDAS), a nonimaging staring infrared MASINT systemThe first experimental ELINT package would fly aboard a photoreconnaissance satellite, Discoverer-13, in August 1960. Translated from the Russian, it was equipped with "Scotop equipment was intended to record the signals of Soviet radars which were tracking the flight of American space objects."


The Viet Minh, at first, used captured French communications equipment. Under the French, no Vietnamese had been trained in cryptography, so, the initial messages were sent in the clear. On September 23, 1945, the US intercepted a message from Ho Chi Minh to Joseph Stalin, requesting aid for flood victims. This traffic immediately triggered more suspicion of Ho's relationship to Moscow, but it turned out to be one in a series of messages to world leaders.

On September 12, the Viet Minh established a Military Cryptographic Section, and, with their only reference a single copy of French Capitaine Baudoin's "Elements Cryptographic", and began to develop their own cryptosystems. Not surprisingly, these were very basic. By early 1946, they had established a network of radio systems, still transmitting with only minimal communications security.

The French had a number of direction-finding stations, with about 40 technicians. By 1946, the French had identified a number of Viet Minh network and were able to do traffic analysis. They also monitored Nationalist and Communist Chinese, British, Dutch and Indonesian communications In general, however, SIGINT in French Indochina was limited by the availability of linguists.

While the US began to provide military supplies to the French, approximately at the time of the start of operations of the Armed Forces Security Agency in 1949, Indochina was a low COMINT priority. Even in 1950, the position of the French there was considered "precarious", both in a Joint Chiefs of Staff assessment and a National Intelligence Estimate.

US domestic surveillance

During this period, several programs, potentially in violation of its foreign intelligence charter, the NSA (and its AFSA predecessor) monitored international telegram and selected voice communications of American citizenscitation
last =Senate Select Committee to Study Government Operations with Respect to Intelligence Activities
title = The National Security Agency and Fourth Amendment Rights
date = OCTOBER 29 AND NOVEMBER 6, 1975
url =
accessdate = 2007-12-07
] .Project SHAMROCK, started during the fifties under AFSA, the predecessor of NSA, and terminated in 1975, was a program in which NSA obtained copies, without a warrant, of telegrams sent by international record carriers. The related Project MINARET intercepted voice communications of persons of interest to US security organizations of the time, including Malcolm X, Jane Fonda, Joan Baez, and Martin Luther King.

Drone technology grows

While there were remote-controlled aircraft in World War II, the technology of the time was inadequate for reliable operation, as demonstrated by Operation Aphrodite. This began to change in 1948, when Ryan cite web
title = RYAN AQM-34G - R
url =
accessdate = 2007-10-12
] won the US Air Force competition for the Q-2 jet-propelled aerial target. Known as the Q-2A Firebee, the jet-propelled UAV, launched by a rocket and recovered by parachute, was also bought by the Navy and Army.

Drones did not have an immediate SIGINT role, but they are so important in later conflicts that the first modern development is worthy of note.

Korean War

Korean coverage was incidental to Soviet and Chinese interests in the Korean Peninsula.

Was there early warning of the Korean War? Perhaps, but hindsight is a wonderful thing. As with the retrospective analysis of COMINT immediately after Pearl Harbor, certain traffic, if not a smoking gun, would have been suggestive, to an astute analyst trusted by the high command. Before the invasion, targeting was against Chinese and Soviet targets with incidental mention of Korea. Prior to 1950 there were two COMINT hints of more than usual interest in the Korean peninsula by communist bloc nations, but neither was sufficient to provide specific warning of a June invasion.

In April 1950, ASA undertook a limited "search and development" study of DPRK traffic. Two positions the second case, as revealed in COMINT, large shipments of bandages and medicines went from the USSR to North Korea and Manchuria, starting in February 1950. These two actions made sense only in hindsight, after the invasion of South Korea occurred in June 1950.

Some North Korean communications were intercepted between May 1949 and April 1950 because the operators were using Soviet communications procedures. Coverage was dropped once analysts confirmed the non-Soviet origin of the material.

Within a month of the North Korean invasion, the JCS approved the transfer of 244 officers and 464 enlisted men to AFSA and recommended a large increase in civilian positions. In August, the DoD comptroller authorized an increase of 1,253 additional civilian COMINT positions. Given the administration's belief that the conflict in Korea could be part of a wider war, only sine of the increase would go to direct support of the conflict in Korea.

COMINT, supported by information from other open and secret sources, showed a number of other military-related activities, such as VIP visits and communications changes, in the Soviet Far East and in the PRC, but none was suspicious in itself. Even when consolidated by AFSA in early 1951, these activities as a whole did not provide clear evidence that a significant event was imminent, much less a North Korean invasion of the South.

In 1952, when personnel levels and a more static war allowed some retrospective analysis, AFSA reviewed unprocessed intercept from the June 1950 period. Analysts could not find any message which would have given advance warning of the North Korean invasion. One of the earliest, if not the earliest, messages relating to the war, dated June 27 but not translated until October, referred to division level movement by North Korean forces.

Tactical SIGINT

UN forces in the Korean War had an assortment of SIGINT units from the various services. On the ground, mountainous terrain, and short supplies of radios among North Korean troops, caused the 1951 reuse of World War I telephone eavesdropping techniques called Ground Return Intercept (GRI). One colonel who participated in the GRI program was heard to remark that the information was so well appreciated by his soldiers that he had little trouble getting volunteers to go out at night and implant the equipment to make intercept possible, even though the sensors might need to be as close as convert|35|yd|m|0 to the enemy.

Starting in July 1951, Low-level intercept (LLI) teams, of 2-5 men in a jeep or bunker, became popular. Although the mobile operations were productive, the jeeps were considered too vulnerable, and operations were "dug in" in bunkers near the main line of resistance, as it was then called. The product was disseminated directly to combat units, usually at regimental level, and was of immediate tactical value: from twenty minutes to three days at best

Little ot much long-term analysis was done - or possible. It thus became difficult to keep continuity on opposing units. These problems were eased somewhat with the creation of an LLI "control section" at ASA headquarters in Seoul in late 1951. This section collated reports from the field and service as a reference source on language problems and OB questions.

Postwar changes in SIGINT, EW and ELINT

The Service Cryptologic Agencies still had their own identity, even after the formation of NSA.

In 1955, ASA took over electronic intelligence (ELINT) and electronic warfare functions previously carried out by the Signal Corps. Since its mission was no longer exclusively identified with intelligence and security, ASA was withdrawn from G-2 control and resubordinated to the Army Chief of Staff as a field operating agency.

Under the US Marines, the 1st Composite Radio Company was activated on 8 September 1959, continuing the World War II legacy.

President Harry Truman, on 24 October 1952, issued a directive that set the stage for the National Security Agency, whose scope went beyond the pure military. NSA was created on 4 November 1952.

Loss of COMINT due to a spy in NSA

ASA in the post-World War II period had broken messages used by the Soviet armed forces, police and industry, and was building a remarkably complete picture of the Soviet national security posture. It was a situation that compared favorably to the successes of World War II. Then, during 1948, in rapid succession, every one of these cipher systems went dark, as a result of espionage by a Soviet agent, William Weisband. NSA suggests this may have been the most significant loss in US intelligence history.

Air Force support

Air Force SIGINT, by the Air Force Security Service, supported numerous Korean War operations. They often gave early warning of bombing attacks or ambushes for fighter aircraft. Since the North Koreans operated under Soviet doctrine, with strict ground control, the ground controlled intercept communications were especially vulnerable. North Korean orders to bombing units might well be intercepted and processed in the US system, before they reached the enemy units. Both ground sites and aircraft intercepted North Korean communications.

An AFSS intercept site, established, in 1951, on Paengyong-do Island, brought sensitive equipment and personnel unacceptably close to the enemy. Security concerns led to the site being abandoned. This served as a feasibility demonstration, and a new, more secure facility was placed on Cho-Do Island. Cho-Do provided both tactical and strategic SIGINT, and a key officer, Delmar Lang, later used the same techniques in Vietnam.

After the Chinese entry into the war, Air Force COMINT, sometimes of tactical communications, allowed UN commanders to prepare for Chinese attacks. Chinese radio communications were limited to higher headquarters, so the UN often knew plans before the unit executing the plan.

Indochina and Vietnam to 1954

"After abolition of the French Indochina opium monopoly in 1950, SDECE imposed centralized, covert controls over the illicit drug traffic that linked the Hmong poppy fields of Laos with the opium dens operating in Saigon." This generated profits that funded French covert operations in French Indochina".

In the spring and fall of 1951, , French forces beat back Viet Minh attacks, but continued to be increasingly hard-pressed in 1953. While the NSA history is heavily redacted, it appears that the French may have provided COMINT to the CIA.

In 1953, the French began their strongpoint at Dien Bien Phu, for reasons the NSA history said were unclear. Factors may have included controlling some restive tribal groups, or, having seen the effect of US firepower in Korea, hoped to draw the Viet Minh into a similar "killing zone". The history mentioned the possibility that the French intelligence service did not want to lose a profitable opium operation in the area, but suggested it was more likely that the Viet Minh were making a profit in this area.

Again concealed by heavy redactions in the NSA history, it appeared that the French had intelligence of multiple Viet Minh units in the Dien Bien Phu area, but no good idea of their size. The overall commander, Henri Navarre, rejected the possibility that these units could be of division size, and that the Viet Minh was capable of a multidivisional operation against Dien Bien Phu.

The NSA history indicates, although the sources and methods are redacted, that the US had very good data on both sides at Dien Bien Phu. As the position crumbled, the French apparently thought that they could get combat assistance from the US. Only the heading of that an NSA emergency force was being considered survived redaction. Nevertheless, while some of the Joint Chiefs did recommend a US relief expedition, President Dwight Eisenhower, as well as Gen. Matthew Ridgway, having just come from the Korean command, rejected the idea of another land war in Asia.

US Submarine SIGINT begins

Under the code names HOLYSTONE, PINNACLE, BOLLARD, and BARNACLE, began in 1959, US submarines infiltrated Soviet harbors to tap communications cables and gather SIGINT. They also had a MASINT mission against Soviet submarines and missiles. The program, which went through several generations, ended when compromised, by Ronald Pelton, in 1981.Citation
author = Jeffrey Richelson
title = The US Intelligence Community, 2nd Edition, Chapter 8, Signals Intelligence
id = Richelson 1989
year = 1989
url =
accessdate = 2007-10-19


SIGINT had much operational impact during this period, with the Cuban Missile Crisis, steady ramping up of warfare in Southeast Asia, and US domestic surveillance. Aircraft, UAV, ship, and ground SIGINT all were in use, and satellite technology left the experimental stage.

Drones evolve further and the impact of the EC-121 shootdown

The Ryan Q-2A evolved further, into the Q-2C Firebee of 1960, and still is a basic subsonic configuration in active service. In 1961, the Air Force requested a reconnaissance version of what was then designated the BQM-34A, which resulted in the Firebee Model 147A, to be designated the AQM-34.RyanDrone] This UAV looked like its target version, but carried more fuel and had a new navigation system. These reconnaissance drones were air-launched from a DC-130 modified transport. Like all subsequent versions of this UAV, it was air-launched from underneath the wing of a specially modified Lockheed DC-130 Hercules, rather than ground-launched with rocket assistance. These are thought to have been operationally for IMINT, although SIGINT was considered, as more aerial US reconnaissance platforms do SIGINT than IMINT, and most IMINT platforms, such as the U-2 and SR-71 also have SIGINT capability. Drones of this version were to be used in the Cuban Missile Crisis.

A major advance for high-risk IMINT and SIGINT missions was the high-altitude AQM-34NRyanDrone] COMPASS DAWN, which flew as high as convert|70000|ft|m|-3 and had a range over 2,400 miles. AQM-34N's flew 138 missions between March 1967 and July 1971, and 67% were parachute-recovered with the new Mid-Air Retrieval System, which used a helicopter to grab the parachute cable in mid-air. While this had an IMINT mission, the potential of high altitude for SIGINT over a wide area was obvious.

In the EC-121 shootdown incident of 15 April 1969, an EC-121M of the U.S. Navy's Fleet Airborne Reconnaissance Squadron One (VQ-1) Vietnam, took off on a routine SIGINT patrol under the BEGGAR SHADOW program. North Korean air search radar was monitored by the USAF 6918th Security Squadron in Japan, and Detachment 1 6922nd Security Wing at Osan Air Base in Korea, and the Naval Security Group at Kamiseya, Japan. The EC-121M was not escorted. When US radar detected the takeoff of North Korean interceptors, and the ASA unit lost touch, ASA called for fighters, but the EC-121M never again appeared on radar. 31 crewmen were lost.

In response to this threat on what had been considered a low-risk mission, Ryan was tasked to develop the AQM-34Q was the SIGINT version of the AQM-34P, with antennas along the fuselage. Underwing fuel tanks were added to this model, and the AQM-34R updated the electronics and had standard underwing tanks.

Early space-based SIGINT

Soviet sources state the first specialized ELINT satellites, which received the designation of "Ferret," was begun in the USA in 1962. In actuality, the first successful SIGINT satellite was the U.S. Navy's Galactic Radiation and Background (GRAB), designed by the U.S. Naval Research Laboratory. GRAB had an unclassified experiment called Solrad, and an ELINT package called Tattletale. Tattletale was also called Canes; CANES was also the National Reconnaissance Office (NRO) sensitive compartmented information (SCI) codeword for the control system overall program. GRAB intercepted radar pulses as they came over the horizon, translated the frequency, and retransmitted each pulse, with no further processing, to ground receiving sites. GRAB operated from 1960 to 1962.citation
url =
title = The NRO at Forty: Ensuring Global Information Supremacy
first1 = R. Cargill | last1 = Hall
] Again examining space-based SIGINT through Soviet eyes, "The tasks of space-based SIGINT were subdivided into two groups: ELINT against antiaircraft and ABM radars (discovery of their location, operating modes and signal characteristics) and SIGINT against C3 systems. In order to carry out these tasks the US developed ... satellites of two types: :*small ELINT satellites which were launched together with photoreconnaissance satellites into initially low orbits and then raised into a polar working orbit at an altitude of 300 to 800 km using on-board engines:*heavy (1 to 2 tonne mass) "SIGINT" (possibly the translator's version of COMINT?) satellites, which were put into orbit at an altitude of around 500 km using a Thor-Agena booster. The Soviet source described the satellites of the late sixties as "Spook Bird" or CANYON , which was the predecessor to the production RHYOLITE platforms. This was not completely correct if the Soviets thought these were heavy ELINT satellites; CANYON was the first COMINT satellite series, which operated from 1968 to 1977.

According to the NRO, the incremental upgrade of GRAB's Tattletale package was POPPY. The second program, Poppy, operated from 1962 to 1977. The "fact of" the Poppy program, along with limited technical information, was declassified in 2004. citation
url =
last1 = MacDonald | first1= Robert A.
last2 = Moreno | first1 = Sharon K.
title = Raising the Periscope... Grab and Poppy, America's early ELINT Satellites
year = 2005
publisher = U.S. National Reconnaissance Office
] At least three NRO operators did the preliminary processing of the POPPY data, one measuring the orbital elements of the satellite and the selected polarization, while the second operator identified signals of interest. The third operator did more detailed, non-real-time, analysis of the signal, and transmitted information to NSA.

Before GRAB and POPPY, US information about Soviet radar stopped about 200 miles from the coastline. After these space systems went into service, effectively all radars on the Soviet landmass became known to NSA. They informed the Strategic Air Command with the technical details and locations of air defense radars, which went into planning attack routes of the Single Integrated Operational Plan (SIOP), the master set of plans for nuclear warfare. They provided operational information to Navy commanders. Coupled with IMINT from CORONA, they helped CIA, DIA and other elements of the intelligence community understand the overall Soviet threat.

The Cuban Crisis and the hotter part of the Cold War

While the start of the Cuban Missile Crisis came from IMINT showing Soviet missiles under construction, SIGINT had had an earlier role in suggesting that increased surveillance of Cuba might be appropriate. NSA had intercepted suspiciously blank shipping manifests to Cuba, and, through 1961, there was an increasing amount of radio chatter suggestive of Cuba receiving both Soviet weapons and personnel. The weapons could be used offensively as well as defensivelyCitation
last = Johnson
first = Thomas R.
last2 = Hatch
first2 =David A.
title = NSA and the Cuban Missile Crisis
date = May 1998
url =
accessdate = 2007-10-07
] .

In September and October 1962, SIGINT pointed to the completion of a current Soviet air defense network in Cuba, presumably to protect something. The key U-2 flight that spotted the ballistic missiles took place on October 15. While the IMINT organizations were most critical, an anecdote of the time, told by Juanita Moody, the lead SIGINT specialist for Cuba, that the newly appointed Director of NSA, LTG Gordon Blake, came by to see if he could help. "She asked him to try to get additional staff to meet a sudden need for more personnel. Shortly she heard him on the telephone talking to off-duty employees: "This is Gordon Blake calling for Mrs. Moody. Could you come in to work now?"

Two RB-47H aircraft, of the 55th Reconnaissance Wing, during the Cuban Missile Crisis were modified to work with Ryan AQM-34 SIGINT UAVs, still launched from DC-130s. The UAVs carried deceptive signal generators that made them appear to be the size of a U-2, and also carried receivers and relays for the Soviet SA-2 surface-to-air missiles on Cuba. In real time, the UAVs relayed the information to the RB-47, which was itself using ELINT sensors against the radar and SA-2 command frequencies. Essentially, the UAV was carrying out a "ferret" probe intended to provoke defensive response, but not jeopardizing the lives of pilots. This full capability was only ready in 1963, and the original scenario no longer held.

During the Crisis, after a U-2 was shot down, RB-47H's of the 55th wing began flying COMMON CAUSE missions, with other US aircraft, to identify any Cuban site that fired on a US plane. The Cubans, however, believed the US threat that such a site would immediately be attacked, and withheld their fire. Crews began calling the mission, as a result, "Lost Cause".Citation
last = Bailey
first = Bruce M
title = The RB-47 and RC-135 in Vietnam
date = 1995
url =
accessdate = 2007-10-12

Tactical Naval SIGINT monitored stopped Soviet transports, when it was unknown if they would challenge the naval quarantine. Direction finding confirmed they had turned around.


Also in 1962, the Central Intelligence Agency, Deputy Directorate for Research, formally took on ELINT and COMINT responsibilitiesCitation
last = Central Intelligence Agency
title = Deputy Director for Research
date = May 1998
url =
accessdate = 2007-10-07
] . "The consolidation of the ELINT program was one of the major goals of the is responsible for::*Research, development, testing, and production of ELINT and COMINT collection equipment for all Agency operations.:*Technical operation and maintenance of CIA deployed non-agent ELINT systems.:*Training and maintenance of agent ELINT equipments:*Technical support to the Third Party Agreements.:*Data reduction of Agency-collected ELINT signals.:*ELINT support peculiar to the penetration problems associated with the Agent's reconnaissance program under NRO. :*Maintain a quick reaction capability for ELINT and COMINT equipment.""CIA's Office of Research and Development was formed to stimulate research and innovation testing leading to the exploitation of non-agent intelligence collection methods....All non-agent technical collection systems will be considered by this office and those appropriate for field deployment will be so deployed. The Agency's missile detection system, Project [deleted] based on backscatter radar is an example. This office will also provide integrated systems analysis of all possible collection methods against the Soviet antiballistic missile program is an example." . It is not clear where ELINT would end and MASINT would begin for some of these projects, but the role of both is potentially present. MASINT, in any event, was not formalized as a US-defined intelligence discipline until 1986.

US operations in Southeast Asia

The NSA History redacted most information, not already public, from 1954 to 1960. A section is titled "Diem's War against Internal Dissent". It opens with an observation that most opposition to President Diem was inflamed by "his program of wholesale political suppression, not just of the Viet Minh cadre that had stayed in the south after Geneva, but against all opposition, whether it was communist or not." By mid-1955, according to Diem, approximately 100,000 Communists were alleged to have surrendered, or rallied to Diem, although the NSA author suggests this did not correspond to political reality, since there were only an estimated 10,000 "stay-behinds". It was clear, however, that the number of communists at large dropped dramatically.

IGINT in Southeast Asia, 1954-1960

The history mentions that his security organs were given a free hand by Ordnance Number 6 of January 1956, putting anyone deemed a threat to the defense of the state and public safety," at least in house arrest. A quote from "Life" magazine, generally considered friendly to Diem, suggested that a substantial number of non-communists had been arrested. This is followed by a brief note, "Yet in that same process of neutralizing opposition, Diem set the seeds for his own downfall." This followed by long redactions. Both Diem and the US Military Assistance Advisory Group (MAAG), according to the NSA history, felt the communists were going into "last gasps" in late 1959.citation
chapter = Chapter 2 - The Struggle for Heaven's Mandate: SIGINT and the Internal Crisis in South Vietnam, [Deleted] 1962
title = Spartans in Darkness: American SIGINT and the Indochina War, 1945-1975
first1 = Robert J. | last1 =Hanyok
publisher = Center for Cryptologic History, National Security Agency
year = 2002
url =

US SIGINT support during the Vietnam War came principally from service cryptographic units, with some NSA coordination. Units still belonged to their parent service, such as the Army Security Agency and Naval Security Group. Some SIGINT personnel were assigned to covert special operations and intelligence units.cite book
last = Gilbert
first = James L.
title = (Review of) The Most secret War: Army Signals Intelligence in Vietnam.
publisher = Military History Office, US Army Intelligence and security Command.
date = 2003
location = Pittsburgh, PA
url =

tructuring the history of SIGINT and Southeast Asia

There are several ways to split US SIGINT regarding Southeast Asia into periods. Gilbert's four periods are focused on the deployment of American units. In contrast, Hanyok's periods, although the redactions make it difficult to see exactly why he created chapters as he did, but it would appear that he ties them more to VC/NVA activities, as well as RVN politics, than the US view.

IGINT and the Development of NVA Logistics

For example, the NVA decision to create the 559th Group and establish the Ho Chi Minh trail, about which there seems to have been significant SIGINT, was in May 1959, the reason for the Group's number. Additional transportation groups were created for maritime supply to the South: Group 759 ran sea-based operations, while Group 959 supplied the Pathet Lao by land routes. citation
first1 = Christopher E. | last1 = Goscha
title = The Maritime Nature of the Wars for Vietnam (1945-75)
url =
date = April 2002
conference = 4th Triennial Vietnam Symposium, Texas Tech University Vietnam Center
] . Gilbert does not consider the dates of creation of the logistics groups, nor does he consider Hanyok's history before US combat troops arrived, but those earlier periods were not his focus. Group 959 also provided secure communications to the Pathet Lao.

Initial Emphasis on Laos

Hanyok emphasizes that the US, in the early 60s, considered Laos, not South Vietnam, the critical area. The Department of Defense prepared alternative operational plans for US combat troops in Laos and Thailand. To support this, "a Laotian Watch Office was set up with twenty-four-hours-a-day operations, seven days a week. A special TDY [temporary duty] team was readied to fly to the ASA site at Clark Air Base to set up a second-echelon SIGINT reporting mission. (SIGINT reporting can be performed at various levels, or echelons. Field site reporting is considered first-echelon. If a unit has no reporting capability, then its intercept is forward to an intermediate site that is considered "second-echelon")". The Laotian situation calmed, but flared again in May 1962. The US again prepared a combat force, made of Seventh Fleet ships that sailed into the Gulf of Siam. A battalion of Marines was airlifted to Udon, to supplement forces already there. NSA again went to a theaterwide SIGINT condition BRAVO, including at the year-old ASA facility at Tan Son Nhut airbase near Saigon.

DRV Logistics and the Ho Chi Minh Trail

Another heading in the NSA history is "Military Group 559, the Construction of the Ho Chi Minh Trail, and the Southern Infiltration 1959-1962". Hanyok explains that the Trail constantly improved, until, by 1974, it was a network of all-weather roads, trails, and pipelines. Again, Hanyok divides the history into periods based on enemy action, while Gilbert divides it on American deployments and changes in technology.

Hanyok writes that the 559th was variously known as a Transportation Group, Division, or Regiment. It had two subordinate regiments, the 70th and 71st, composed of truck, roadbuilding, and other operational functions. The 559th itself was subordinated to the General Directorate Rear Services (GDRS). From the SIGINT standpoint, the Trail began at two major supply-heads, Vinh Linh and Dong Hoi, which were the intermediate headquarters running the infiltration-associated radio nets from 1959 until late 1963. They disappeared in September 1963, although Vinh Linh became the headquarters of the 559th.

Early days: American and Operational Perspective

In January 1961, while the Vietnam embassy and military group prepared a counterinsurgency plan, the SIGINT community did its own planning. The first review of the situation assumed limited support to the ARVN COMINT teams. Essentially, the policy was that the South Vietnamese would be trained in basic direction finding using "known or derived" technical information, but, for security reasons, COMINT that involved more sophisticated analysis would not be shared. It was also felt that for at least the near term, ARVN COMINT could not provide meaningful support, and the question was presented, to the State Department, if it was politically feasible to have US direction-finding teams operate inside South Vietnam. The March 1961 plan included both tactical support and a strategic COMINT mission collection NVA data for NSA.

Eventually, the idea was that the South Vietnamese could intercept, but send the raw material to the US units for analysis. Two plans were created, WHITEBIRCH to increase US capability throughout the region but emphasizing South Vietnam, and SABERTOOTH to train ARVN personnel in basic COMINT. Concerns over ARVN security limited the information given them to non-codeword SECRET information. The first step in WHITEBIRCH was the 400th ASA Special Operations Unit (Provisional), operating under the cover name of the 3rd Radio Research Unit (RRU).

The 3rd RRU soon had its first casualty, SP4 James T. Davis, killed in an ambush. Soon, it was realized that thick jungle made tactical ground collection exceptionally dangerous, and direction-finding moved principally to aircraft platformscitation
last = Knight
first = Judson
title = Army Security Agency
url =
accessdate = 2007-10-08
] .

Although SIGINT personnel were present in 1960, Gilbert breaks the ASA involvement in Vietnam into four chronological phases, which do not match the more recent NSA history by Hanyok, which is less focused on events with the US military. :# The Early Years: 1961-1964, characterized by direction-finding and COMSEC, ending with the Gulf of Tonkin Incident. This partially overlaps the period of "SIGINT and the Attempted Coups against Diem, 1960-1962":# The Buildup: 1965-1967, with cooperation at the Corps/Field Force level, and the integration of South Vietnamese linguists. Major ASA units at this time were the 509th Radio Research Group and 403d RR (Radio Research) SOS (Special Operations Detachment):#Electronic Warfare: 1968-1970, with substantial technical experimentation:#Vietnamization: 1971-1973, as the mission shifted back to training, advising, and supporting South Vietnamese units.

Early Air Force strategic SIGINT

DC-130 launchers and controllers were deployed to Kadena in Okinawa, and the Bien Hoa in Vietnam. The real-time telemetry, hoped for during the Cuban crisis, was now a reality, and RB-47H ELINT aircraft were dedicated to Southeast Asian operations.

RC-135Ms were flying at the same time, but primarily against China and Russia. Eventually, their missions focused on Southeast Asia.Bailey1995]

First-generation Army tactical SIGINT aircraft

RU-6A Beaver aircraft equipped with airborne radio direction finders (ARDF) were the first Army reconnaissance aircraft in South Vietnam, arriving in March 1962 and assigned to the Flight Detachment of the 3rd Radio Research Unit. Citation
last = Love
first = Terry M.
title = 335th Radio Research Company: Winged Recon
year = 2000
url =
accessdate = 2007-10-12
] More RU-6A's, now code named SEVEN ROSES, arrived in 1963, along with RU-5D Seminoles with the code name CHECKMATE, and a RU-8F.

Initial direction finding was unsatisfactory, and various additional aircraft were added, including more RU-6A and RU-8Ds, a single RCV-2B Caribou codenamed PATHFINDER, a RU-1A Otter coded CAFE GIRL, and RU-1As under the codes HAPPY NIGHTS and LAFFING OTTER. CHECKMATE, with AN/ARD-15 surveillance equipment, proved successful, and was extended to the Beavers and the U-8Ds.


The USMC 1st Composite Radio Company deployed, on January 2, 1962, to Pleiku, South Vietnam as Detachment One under the command of then Captain John K. Hyatt, Jr. On September 17, 1963 in was redesignated as 1st Radio Company, Kaneohe Bay, Hawaii. 1st Radio Battalion - 14 July 1964, but apparently still put detachments into Vietnam.

Upgraded to the 1st Radio Battalion, Fleet Marine Force (FMF), in Hawaii in July 1964, it deployed to Danang as 1st Radio Battalion, FMF, Camp Horn, Danang, South Vietnam

Early Days: Vietnamese and Strategic perspective

1960, however, opened with a "disaster for the South Vietnamese" in Tay Ninh province, followed by a number of battles lost. To SIGINT analysts at NSA, the increase in communications activity in 1960 indicated a strong growth of the communists. By the end of the year, NSA estimated that the number of stations had quadrupled, with the communications activity in the Saigon area growing sixfold or sevenfold. The increased communications activity, according to the history, was so striking that Allen W. Dulles, the Director of Central Intelligence and head of the intelligence community, personally went to President John F. Kennedy, in January 1961, to brief him on the increase.

IGINT and the Attempted Coups against Diem, 1960-1962

A section entitled "SIGINT and the Attempted Coups against Diem, 1960-1962", opens, on 11 November 961, with the sounds of a coup attempt in Saigon. "Diem's luck held. The coup leaders were disorganized and amateurish. Rather than seize the palace [where Diem and his brother were barricaded] , they preferred to talk. They also failed to capture the radio stations and other communications centers and failed to set up roadblocks..." and other obstacles to loyalist troops, who caused the coup members to flee, often to Cambodia. "American SIGINT had been surprised by the coup, as had American intelligence in general. In the coup's aftermath, SIGINT discovered, through decrypted VC regional headquarters messages, that the communists were taking an active interest in the failed coup, learning valuable lessons from its shortcomings, which would translate into plans to take advantage of any future maneuvers against Diem.

Intercepts also made it clear that the attempted coup by paratroopers had surprised the Communists as much as Diem. "In the mad scramble for positioning that followed, the Viet Cong in the Nam Bo [Saigon] region directed subordinate elements to help soldiers, officers and others (politicians and security personnel) involved in the coup to escape." This was followed by long redactions, and then the question, "Were the Communists on to something? There is no doubt that they were correct in their assessment that the Americans were disillusioned with Diem's failure to select a course of social reform and stick with it." They believed the Americans were contacting dissidents and planning new coups, but NSA states there was no evidence of American involvement; the South Vietnamese were more than capable of planning their own.

Creation of the National Liberation Front

On 20 December 1960, the National Liberation Front (NLF) was established. "the formation of the NLF probably marked the final eclipse for any viable, independent, noncommunist and nationalist alternative to Diem's rule. As far back as the 1930s, noncommunist nationalist organizations had essentially been destroyed by the French colonial security ("surete") apparatus." Nationalist alternatives to the Communists or Diem had not been a viable option for decades.

Alerts over Soviet and Chinese Airlift

While much text was redacted, the NSA history indicates there was major concern, in December 1960, about a Soviet airlift of supplies, and a "real concern that either the Soviets or the Chinese Communists, or both, would go beyond the supply flights and directly intervene in the fighting. On 14 December 1960, the NSA director, VADM Laurence L. Frost, institute a SIGINT Readiness Condition BRAVO on a theaterwide level throughout the Far East." The nature of BRAVO was not given, and the theater went back to ALPHA, apparently the lowest, by February 1961, when the intelligence community (IC) decided there was no chance the Soviets or PRC would join the fighting.citation
chapter = Chapter 3 - "To Die in the South": SIGINT, the Ho Chi Minh Trail, and the Infiltration Problem, [Deleted] 1968
title = Spartans in Darkness: American SIGINT and the Indochina War, 1945-1975
first1 = Robert J. | last1 =Hanyok
publisher = Center for Cryptologic History, National Security Agency
year = 2002
url =

America Plans the Mainland SIGINT Buildup, [deleted] -1961

By late 1960, the SIGINT community was detecting increased activity in South Vietnam and Laos, and there were not enough assets to meet the needs for intelligence. A section headed "America Plans the Mainland SIGINT Buildup, [deleted] -1961" begins with a statement that in 1959, "the problem of American cryptology in Southeast Asia could be seen by looking at a map of SIGINT sites in the larger Asian region." After over a page of deleted material, it was said that most coverage came from three sites in the Philippines, which provided about 450 hours per month of monitoring the DRV. After deletions, the comment is made that the "more general traffic analysis situation was deemed barely sufficient to establish a "skeletal" technical continuity for radio station and network identification and provide data for a realistic estimate of the total communist communications problem. Direction finding support for the DRV transmitters was "insignificant"". I can be suggested that since the material after the redactions spoke of traffic analysis as more general, the redacted sections dealt with message content interception, cryptanalysis, and translation.

While the methods were not yet called MASINT, there was a Special Identification Techniques (SIT) facility at the ASA site at Clark AFB could use to do "radio fingerprinting" to recognize unique Morse code operator "fists". This revealed little, and the problem was traced to inadequate direction finding. After deletions, it is observed that NSA concluded it needed another 105 intercept stations, giving over 2400 hours of coverage.

The solution suggested, which was described as harder to implement than had been realized, was to put the intercept stations in Thailand. Under treaty limitations of the time, the US was not allowed to bring enough personnel into South Vietnam to run the needed intercept positions. BSA looked for a facility, in Thailand, big enough for 800 intercept positions. The Thai government, however, was "skittish".

Increased activity by the Pathet Lao, however, concerned the Thai government, and the US planned, and presented to Thailand, a contingency plan for defending Thailand against Laotian communists. Thailand would have full access to SIGINT affecting its own security.

When the Thai government agreed, however, it caught the US by surprise, and the personnel to establish the facility were not immediately available. Several alternatives were explored, but were rejected because they would take too many resources from combat units. Eventually, an ASA contingent was put together from resources in the Philippines.

Thailand imposed a limit of fifty SIGINT personnel for the site, which eliminated the possibility of adequate direction finding. The compromise was to intercept at the site, but to send the raw data to the Philippines for processing. Thai sensitivities were such that a permanent site was not selected until 1965, when the Udon base was established. Udon would be the only NSA facility in Southeast Asia after the American withdrawal in 1973.

The buildup: 1965-1967

After a regiment of PRC MiG-17 fighters arrived at Mengtzu in 1963, SIGINT predicted jet fighters would enter the DRV air defense network. This was reinforced with learning that high-level DRV and PRC personnel would have a meeting at Mengtzu in May 1964.

The Gulf of Tonkin incident, in August 1964, involved two-destroyer DESOTO patrols equipped with intercept vans, backed up with carrier air patrolscite web
last = National Security Agency
authorlink = National Security Agency
title = Gulf of Tonkin
work = declassified materials, 2005 and 2006
date = 2005-11-30 and 05/30/2006
url =
accessdate = 2007-10-02
] .

Early DRV Air Defense Buildup

In the weeks immediately following the Gulf of Tonkin incident, the most important SIGINT role was providing defensive information to US air strikes. This was done at three levels of generality. First, overall monitoring of the DRV air defense network, SIGINT could maintain situational awareness of North Vietnamese tracking via radar and visual observers. Second, SIGINT detected the activation of specific weapons systems in the air defense network, such as SA-2 surface-to-air missiles (SAM), anti-aircraft artillery (AAA), and fighter interceptors. Finally, it could detect immediate threats, such as missile launches or impending attacks by fighters.citation
chapter = Chapter 6 - Xerxes' Arrows: SIGINT Support to the Air War, 1964-1972
title = Spartans in Darkness: American SIGINT and the Indochina War, 1945-1975
first1 = Robert J. | last1 =Hanyok
publisher = Center for Cryptologic History, National Security Agency
year = 2002
url =

Reports from the roughly 40 visual observation stations were sent to sector headquarters, which controlled AAA. These reports were sent by high-frequency (HF) Morse code radiotelegraphy, in standardized message formats where only the specific details needed to be transmitted. It could take up to 30 minutes for a report to work its way through the system, so that more specific tracking or interception orders could be given. According to the NSA history, air defense communications did not change significantly during the war, so COMINT analysts were able to become very familiar with its patterns and usage.

Command and control applied to four system components: air warning from radar and observer stations, limited radar tracking, AAA and SAMs, and fighters. Rapid upgrades started to go into place after the Gulf of Tonkin incident, with the arrival, within two days, of 36 MiG-15 and MiG-17 fighters. These arrived from China and were probably flown, at first, by Chinese pilots, but Vietnamese pilots were soon in familiarization flights.

Two main communications links between the DRV and PRC were established, from Hanoi to Kuangchow and K'unming. These liaison networks allowed access to Chinese radar covering the Gulf of Tonkin, Laos, and Hainan Island, as well as the DRV itself. By 1967-1968, there were approximately 110,000 persons in the DRV air defense system, supporting 150 radars, 150 SAM sites (rarely all active at the same time), and 8,000 AAA pieces. There were 105 fighters, including the MiG-21. At any given time, one-third to one-half of the fighters were based at PRC airfields.

Air Defense headquarters was at Bac Mai. By January 1966, all major air defense installations, including those in the PRC, were linked by a common HF radio network with standardized procedures. There was an Air Situation Center and an Air Weapons Control Staff. The latter assigned targets to the various defense weapons.

A wider range of communications systems emanated from Air Defense Headquarters, including VHF voice, landlines, and HF/MF. Due to the need to move information quickly, without any automation, most communications were either in low-grade ciphers or were unencrypted.

The DRV system matures, 1965

North Vietnam's air defense system, as of 1965, had three main subsystems::#Radar detection and tracking:#Situational awareness (senior controller at Bac Mai):#Tactical fighter direction (Phuc Yen, Gia Lam, Kep):#Airborne fighters:#SAMs and AAA

In 1965, the DRV had full radar coverage, with Chinese input, out to 150 miles from its borders. Detection and processing times dropped to five minutes. In contrast, the US did not have full radar coverage over the DRV, and SIGINT was seen as a way of filling the gaps in US knowledge of their air defense operations.

Intensified USAF SIGINT

Under several code names, the last being UNITED EFFORT, the earlier combination of Okinawa-, and then Bien Hoa (Vietnam) based RB-47H ELINT aircraft and drones, originally planned for Cuba, was tried again in 1964, but without the blip-enhancing electronics that would make the North Vietnamese think it was a U-2. The North Vietnamese did not take the bait. Eventually, in 1966, the North Vietnamese shot down a drone, but everything worked and the entire electronic score of the SA-2 symphony was recorded. Bailey1995]

Some of the first airborne SIGINT platforms were C-130 QUEEN BEEs, operational by early 1965. They flew two monitoring orbits, one over northwest Thailand and the other over the Gulf of Tonkin. Apparently, there was never a satisfactory basing arrangement for them, although they worked with analysts at Danang. Redactions make it impossible to understand their full pattern, but they did, under undefined circumstances, land at Danang. Also in early 1965, a large number of US Air Force Security Service (USAFSS) moved from the Philippine Islands (PI) to the Republic of Vietnam.

While the RB-47H's were retired after the 1966 success, the RC-135Ms of the 82nd Strategic Reconnaissance Squadron moved from Japan to Okinawa, in the 4252 Strategic Wing. Tasking increased until those SIGINT platforms were flying daily, then 24-hour coverage under the COMBAT APPLE program, still flying a weekly mission against China or Russia.

COMBAT APPLE missions initially flew over the Gulf of Tonkin, including a refueling station just south of the Demilitarized Zone. The location of the refueling position allowed them to continue collecting SIGINT while drawing fuel from the tanker.

Often just after the COMBAT APPLEs refueled, North Vietnamese MiG-21 fighters would try a single supersonic pass at the COMBAT APPLE aircraft, firing everything and immediately turning back, almost out of fuel. The ungainly RC-135's were heavily loaded and had little ability to maneuver, and no defensive systems. Luckily, none were lost, but carrier-based fighters were soon ordered to escort them. There was a period during which the Navy aircraft fell into a pattern of leaving the RC-135 for their own refueling, and the North Vietnamese tried more attacks when the US fighters flew away. Eventually, better tactics were evolved, including using multiple fighter flights and the RC-135 as bait in what turned out to be an ambush for the MiGs, from a pair of fighters that flew in close formation with the RC-135 and did not show separately on radar.

Obviously, this constant workload stressed the RC-135M's, which periodically had to go back to the US for major maintenance. Attempts were made to fill the vacancy with RC-135D's from Alaska, but aircraft from there, aside from having smaller engines, did not adapt to the tremendously different climate

While ELINT helped against the SAM threat, the first kill of a US aircraft by an SA-2 SAM took place in mid-1965. The DRV air defense network was improving, and, by the end of 1965, were processing tracking reports in 5 minutes, a procedure that previously took 30 minutes.

The classic battle between national-level SIGINT and direct support of operations occurred, and a compromise was reached to put a 7th Air Force SIGINT Support Group at Danang. Still, many SIGINT units moved from Vietnam to Udon, Thailand, between 1965 and 1967.

hip-based SIGINT

Dedicated SIGINT ships, built on merchant hulls, were also used, but proved too vulnerable and slow. An intermediate size, such as Pvt Jose F. Valdez (T-AG-169) operated around Africa from 1961 until 1969. "Valdez" was too slow to reach the patrol area to which the "Liberty" was sent. The larger Belmont-class included the USS Liberty (AGTR-5), attacked by Israel in 1967. Modern ship installations generally involve intercept stations in mobile vans, which can be put onto the deck of a warship, which can protect itself as the "Pueblo" and "Liberty" could not. Why this level of protection was not available in 1967 is difficult to understand.

Starting in 1965 and continuing until the end of the AGTR program in 1969, two "technical research" SIGINT ships, AGTR-1 "Oxford" and AGTR-2 "Jamestown", sailed up and down the coast of Vietnam, acting as "firemen" to fill gaps in land-based coverage. They also participated in calibrating airborne direction finding.

During this time period, the Medal of Honor was bestowed on the captain of the AGTR-5, "USS Liberty", for his leadership following an Israeli attack on his ship.cite web
last = National Security Agency
authorlink = National Security Agency
title = USS Liberty
url =
accessdate = 2007-10-02
] .

A class of even smaller vessels included the Banner-class, including the USS Pueblo (AGER-2), captured by North Korea in 1968.

econd-generation Army tactical SIGINT aircraft (part 1, see 1970s for continuation)

In 1968, the Army introduced the RU-21D LAFFING EAGLE, as an incremental improvement in the long series of RU-21 aircraft, still operational today. The aircraft were technical improvements over their predecessors, but were very maintenance intended. After American forces withdrew from South Vietnam, some RU-21D's went to Thai bases, and all returned to the US in 1975.

US domestic surveillance

Project SHAMROCK and Project MINARET were active through the sixties, and terminated in 1975.

IGINT in support of monitoring French atmospheric nuclear tests

After Algerian independence, France moved its test range to French islands in the Tuamoto Archipelago in the Western Pacific. Typical monitoring scenarios for tests in 1968 and 1970 involved NSA COMINT determining that a French test was imminent. Upon that notice, KC-135R tankers, temporarily modified to carry MASINT sensors, would fly around the test area, as part of Operation BURNING LIGHT. [cite web
last = Strategic Air Command
title = SAC Reconnaissance History January 1968-June 1971
url =
accessdate = 2007-10-12|format=PDF
] .

French operations in Africa

According to Pike, in the early 60s, the SDECE, including SIGINT. by the prime minister Michel Debre, and was particularly efficient in the struggle against the rebellion in Algeria. After the disappearance of Mehdi Ben Barkain 1965, De Gaulle made SDECE military again, reporting to the Minister of Defense. He wrote that De Gaulle authorized covert operations, in Quebec, under the rubric of "Assistance et Cooperation Technique" or "Operation Ascot." Pike further states that SDECE, under Foccart, tried, in 1968, to wrest control of Nigerian oil from Britain and the US by arming and supplying secessionists in Nigeria's Biafra region.


The Vietnam War enters its final phases

Elements of the 1st Radio Battalion, USMC, returned to Vietnam in the 1970s, attached to the 9th Marine Amphibious Brigade, operating principally from shipboard platforms. In October 1970 Marine radio units were attached to a US Army unit in Udon Thani, Thailand, but the unit redeployed to Hawaii in 1971.

IGINT and Son Tay

Planning of the Son Tay POW rescue, which had begun in April, was well underway before SIGINT personnel were involved. In August, the JCS asked CINCPAC to assign a representative to the project, and the head of SIGINT support to the Pacific Air Defense Analysis Center was picked. Planning was tightly compartmented, with the NSA participation codenamed ADRENALIN. Various other SIGINT flights and the move of the Monkey Mountain facility had to be changed without revealing the reason. During the raid, however, there was airborne SIGINT support from EC-121 COLLEGE EYE aircraft equipped with the RIVET GYM package for SIGINT and IFF interrogators, as well as COMBAT APPLE RC-135. SIGINT met all expectations, but, of course, did not change the result of the raid.

econd-generation Army tactical SIGINT aircraft (continued)

LAFFING EAGLE increased RU-21 series capability by adding a second SIGINT operator, receivers with a greater frequency range, and an AN/ASN-86 Internal Navigation System. The new system proved very difficult to maintain, however, requiring constant support from contractor representatives and a convert|40|ft|m|0|sing=on trailer full of test equipment. Later on, the V-SCAN system, which gave 240-degree direction-finding coverage centered around the nose and tail, was added to the RU-21Ds. Those aircraft arrived in Vietnam in December 1968 and heavily used. Citation
title = 335th Radio Research Company: Winged Recon
last = Love
first = Terry M.
year = 2000
url =
accessdate = 2007-10-12

WINE BOTTLE and CEFISH PERSON systems, on RU-6A and RU-8D aircraft, were generally unsatisfactory and the 156th Radio Research Company, using these aircraft, redeployed to the US. These aircraft were incapable of true goniometric ARDF, and had to fly over the emitter, dangerously, before pinpointing it.Love]

MASINT sensors to "fingerprint" equipment and operators, first coded SHORT SKIRT and then LEFAIR KNEE, went onto 12 RU-8D airplanes. They were assigned to the 509th Radio Research Group, although some were detached for a time. Some received side-looking airborne radar (SLAR), a MASINT RADINT sensor that later became standard on the OV-1B Mohawk.

LEFT BANK, introduced in 1970, was a first attempt for 360-degree coverage, which was perfected as LEFT JAB on the JU-21A series. LEFT JAB was the first Army system that used an airborne digital computer to combine DF and inertial navigation information. The next refinement, LEFT FOOT, combined the LAFFING EAGLE's sharper DF feature with the LEFT JAB computer, creating the RU-21E aircraft. Very few LEFT FOOT aircraft flew in Vietnam.

CEFIRM LEADER, first known as CRAZY DOG, was an attempt to build a system, called V-SCANARDF, the combined intercept, direction finding, and jamming for the 2-80 MHz frequency range. Implementation involved one of the features to appear in the much later Guardrail series, using several aircraft in a team. RU-21A's carried AN/ARD-22 direction finders. RU-21B's were COMINT intercept aircraft with the AN/ALT-32. RU-21C's carried AN/ALT-29 jammers. The system never worked well, although RU-21D and RU-21Es got it working, and served into the 1990s.

Air Force strategic SIGINT continues

COMBAT APPLE aircraft began to gather SIGINT overland, over the Ho Chi Minh trail and Laos. They went without fighter cover, and in the threat envelope of antiaircraft guns and missiles. When the US detected the antiaircraft weapons, it quickly attacked them, and the North Vietnamese quit trying to shoot down the COMBAT APPLEs.

Several other ELINT versions of the RC-135 flew out of Kadena for specialized ELINT collection, with some aircraft flying missions of 24 hours and more while still based at Offutt AFB, Nebraska, in the US.

Flying from Kadena, the RC-135C model, called the "Chipmunk" after cheek-like antenna pods, were especially effective. They were equipped with an extremely powerful SIGINT system, the AN/ASD-1. This system intercepted, located, and otherwise characterized virtually every signal, recording it all for subsequent analysis. The C models were tasked for worldwide missions, and it only became available for Vietnam on a special mission basis. Of the Vietnam-era SIGINT aircraft, the RC-135U COMBAT SENT was the most advanced, with only two in the Air Force. Even with its limited availability, it provided important information about North Vietnamese missiles.Bailey1995] The COMBAT SENT had extensive ELINT plus a large side-looking radar.Citation
title = The Spyflight Website
date = 1 Jan 2007
url =
accessdate = 2007-10-12

Army SIGINT and Vietnamization

Until 1973, US SIGINT advisors worked with the South Vietnamese. After the cease-fire, according to the CINCPAC Command History [cite web
last = CINCPAC (US Commander-in-Chief, Pacific)
title = CINCPAC Command History, 1973, Volume 1
url =
id = CINCPAC73
accessdate = 2007-10-12 |format=PDF
] . certain US programs continued. The Southeast Asia Airborne Communications Program (ACRP), a program whose plaintext name was classified TOP SECRET, continued. It operated no closer than convert|50|nmi|km|0s (nmi) to the North Vietnamese coast, except it was not to come with convert|19|nmi|km|0|abbr=on of Bac Long Island. Fighter cover for this patrol was discontinued. The ACRP flights had been conducted by a detachment of Navy electronics squadron VQ-1, which relocated from Danang, South Vietnam, to Cubi Point Naval Air Station in the Philippines. Discussions among CINCPAC, Navy and Air Force operational commanders, about surveillance of the Gulf of Tonkin were underway, but came to no conclusion in 1973.

Army Airborne Radio Direction Finding (ARDF) in South Vietnam was phased out. RU-8 aircraft left South Vietnam in mid-January. Operations by RU/JU-21 aircraft were reduced, but not eliminated until March 9; they had conducted continuing operations over the northern part of South Vietnam, the DMZ, and the Laotian Panhandle. 22 EC-47 aircraft remained in Thailand, but 10 others remained in Danang. The Danang force was operated into February by the US, and then turned over to the South Vietnamese.

US attempt to improve coordination among the Service Cryptologic Elements

A separate SIGINT and communications security organization, or Service Cryptologic Element (SCE), existed for the US Army, Navy, and Air Force. Some of the differences were quite appropriate to support of the military operations of the particular service; the Air Force would be interested ELINT about =air defense radars that a bomber might take in attacking the Soviet Union over a polar route, while the Navy would be more interested in coastal air defense radars. The Army would want to be able to recognize hostile artillery fire control radars, and also how to do tactical direction finding, traffic analysis, and field-level cryptanalysis against opposing ground forces.

All of these services also had capabilities to provide national-level intelligence more appropriate for NSA's mission than for support to military operation. The Army had both fixed and mobile intercept equipment appropriate for long-term listening to ground stations, while the Air Force and Navy could probe new foreign electronic systems as part of national-level intelligence goals.

Even though NSA proper had been formed in 1952, the activities of the Service Cryptologic Agencies were not well coordinated. The Air Force and Navy, for example, might duplicate efforts in probing North Korean radars. Air Force RIVET JOINT RC-135 aircraft collected COMINT of interest to all the services. Navy P2 and P3 electronic capabilities also collected data of relevance to the military as a whole.

Bamford described the first effort to organize the SCEs was to create a "fourth branch" of the military, which triggered intense bureaucratic resistance from the services. A compromise was reached by creating the Central Security Service (CSS). The Director of the NSA (DIRNSA) acquired a "second hat" as the commander of CSS. Just as the services rotated the DIRNSA assignment among their three-star (or three-star eligible) intelligence officers, the actual chief of CSS, reporting to DIRNSA, was a two-star post that also rotated among the services. cite book
title = Body of Secrets: Anatomy of the Ultra-Secret National Security Agency
first = James | last = Bamford
publisher = Doubleday
year = 2001
ISBN-10 = 0385499078
] Bamford describes CSS in different ways. At one point, he speaks of "a former senior NSA official who described it as 'a half-assed, last-minute job' designed to destroy the original fourth-service proposal." Later in the same book, however, draws attention, however, to the almost unparalleled power vested in the DIRNSA through NSCID No. 6, revised on 17 February 1972, "All instructions issued by the Director under the authority provided in this paragraph shall be mandatory, subject only to appeal to the Secretary of Defense." Thus, the DIRNSA is able to bypass "not only the Joint Chiefs, but even the secretaries of the branches" giving him his own SIGINT Army, Navy, Air Force, and Marines.

The idea of a fourth service branch for SIGINT is not unheard of; "NSA’s Canadian cousin, the Communications Security Establishment (CSE) relies entirely upon the Canadian Forces Supplementary Radio System (CFSRS) for all raw SIGINT collection. CFSRS has been a part of the Canadian Forces Information Operations Group (CFIOG) since the latter was established 08 May 1998."citation
title = NSA’s Central Security Service
first = Keith P. | last = Clive
url =
year = 2002
] Clive uses the example of the Navy SCE, as of 2002, as showing the significance of organizations under CSS control: "the Naval Security Group (NSG) might be the best indicator of the significance of the military contribution to NSA’s SIGINT efforts. According to Steven Aftergood of the Federation of American Scientists (FAS), the NSG is responsible for "Signals Security matters and, for Data Link Vulnerability Assessment Methodology within the Navy Vulnerability Assessment Program." The Naval Security Group Command (NSGC) "coordinates with, tasks as appropriate, and appraises the efforts of commands and offices of the Department of the Navy and NSA/Central Security Service in the fulfillment of Navy logistics support requirements, as directed by the Secretary of Defense. It also participates in NSA studies as required." The cryptologic staff "work with some of the most sophisticated and complex systems the Navy has to offer in performance of their mission." NSGC’s Commander "reports to the Chief, Central Security Service (CSS) as the Navy Element Commander of the CSS and performs cryptologic functions at the National level as the Commander of the Navy's Service Cryptologic Element (SCE)." Considering just NSG’s structure, naval SIGINT, and by inference all military SIGINT, does not appear to be a mainly nominal entity. Certainly, with the information overload that the Internet has brought, even for NSA, they can use all the help they can get."

US domestic surveillance by NSA

A Senate Select Committee, generally called the Church Committee, began some of the first public hearings on US intelligence. These hearings revealed information that was questionably legal, and led to the termination of some programs, such as Project SHAMROCK and Project MINARET, as well as enacting, in 1978, the Foreign Intelligence Surveillance Act (FISA). FISA established guidelines for COMINT involving US citizens, and established a special FISA Court to approve warrants. The FISA judges were cleared for all intelligence information relevant to warrant requests.

During these hearings, the Director of NSA, LTG Lew Allen, discussed targeting of information, including the names of American citizens, in watch lists: "The use of lists of words, including individual names, subjects, locations, et cetera, has long been one of the methods used to sort out information of foreign intelligence value from that which is not of interest. In the past such lists have been referred to occasionally as watch lists, because the lists were used as an aid to watch for foreign activity of reportable intelligence interest. However, these lists generally did not contain names of U.S. citizens or organizations. The activity in question is one in which U.S. names were used systematically as a basis for selecting messages, including some between U.S. citizens, when one of the communicants was at a foreign location."

Richard M. Nixon ordered the CIA to gather information on foreign sources of controlled substances and how they entered the US. As part of this initiative, the Bureau of Narcotics and Dangerous Drugs (BNDD) requested NSA COMINT related to foreign drug traffic, including watch lists with some U.S. names. International drug trafficking became a formal US Intelligence Board (USIB) requirement in 1971. Other target names for watch lists, concerned with North Vietnam, came from the Defense Intelligence Agency.

During the hearings, LTG Allen said he had received a letter, on October 1, 1973, from Attorney General Elliot Richardson "indicating that he was concerned with respect to the propriety of requests for information concerning U.S. citizens which NSA had received from the FBI and Secret Service. He wrote the following:

"Until I am able more carefully to assess the effect of Keith and other Supreme Court decisions concerning electronic surveillance upon your current practice of disseminating to the FBI and Secret Service information acquired by you through electronic devices pursuant to requests from the FBI and Secret Service, it is requested that you immediately curtail the further dissemination of such information to these agencies."

trategic SIGINT satellites for NSA

From 1972 to 1989, low earth orbit SIGINT satellites were launched only as secondary payloads with KH-9 and KH-11 IMINT satellites. They were code-named after female sex symbols, such as RAQUEL, FARRAH, BRIDGET and MARILYN.

Four geosynchronous RHYOLITE satellites were launched in the seventies, with COMINT and TELINT missions.citation
title =Encyclopedia Astronautica
chapter = Rhyolite
url =
] These were reported to be directed against line-of-sight microwave, telemetry, or both. Their signals downlinked to Pine Gap station in Alice Springs, Australia. According to "Encyclopedia Astronautica", the downlink was in a remote location, to prevent Soviet or Chinese SIGINT personnel from intercepting the downlink, and, in turn, discovering the targeting of the satellites. Downlinked data was then encrypted and retransmitted to NSA at Fort Meade, MD.

The project became unusually public as it was the key element in the espionage trial of the 'Falcon and the Snowman', Boyce and Lee. Rhyolite was also known as Program 720, Program 472, and Aquacade. After having the name compromised when Christopher Boyce sold information to the Soviets, the code name was changed to AQUACADE. In the late seventies, another class of geosynchronous SIGINT satellites, first called CHALET and renamed VORTEX after the code name was compromised. After the loss of Iranian monitoring stations, these satellites were also given an TELINT capability.

JUMPSEAT ELINT satellites, using a Moliyna orbit, started launching in 1975. Their launch parameters were very similar to the SDS communications satellites used for connectivity in high latitudes, and individual launches could easily have been either JUMPSEAT or SDS.citation
title =Encyclopedia Astronautica
chapter = Jumpseat
url =
] While the primary mission of JUMPSEAT constellations appeared to be microwave COMINT, they may also have had ELINT capabilities.


This was a decade of world change, with changes in Cold War emphasis and alliances, the first submarine attack since World War II in the context of a regional war involving extensive power projection, low- and medium-intensity operations, and continuing national policy development.

1980s Cold War SIGINT

Roughly from the late 1980s on, there was cooperation between the US and the PRC in collecting SIGINT of mutual interest, principally against Russia [Citation
last = Association of Former Intelligence Officers
title = China SIGINT Capabilities
work = Weekly Intelligence Notes #15-01
id = ChineseSIGINT
date = 16 April 2001
year =
url =
accessdate = 2007-10-08
] . It is believed that the Qitai and Korla sites, in Xinjiang (Sinkiang) are operated jointly by the Chinese and the US CIA Office of SIGINT Operations against Soviet missile tests and space launches, but their current status is uncertain.

Spruance-class destroyers sailed on collection missions in the Black Sea, Baltic Sea, and off the coast of Libya, a Soviet client.

1980s Middle East SIGINT

UN peacekeepers deployed to Beirut in 1983, with US 1st Battalion 8th Marines, which lost 241 men, in the bombing that also killed 58 French paratroopers of 3rd Company of the 6th Parachute Infantry Regiment.

SIGINT teams were attached to the Marine force there. Unfortunately, SIGINT had little role to play in the force protection problem.

Western hostages were a major concern to the US and UK. The US approach was the Iran-Contra Affair arms-for-hostages swap. Urban wrote SIS learned about the plan, although the UK had not been officially told about it.Citation
author = Mark Urban
title = UK Eyes Alpha: the Inside Story of British Intelligence. Chapter 5: Zircon
id = Urban 1996
url =
accessdate = 2007-10-19
] The British did not discuss their information, learned from a HUMINT source, with the US, according to one British officer "All we could do was tuck it away in a box, we couldn't have discussed it with them. This was UK Eyes Alpha, after all!" Britain may later have gotten information from the US, which, according to Andy McNabCitation
author = "Andy McNab" (pseudonym)
title = Bravo Two Zero
year = 1994
url =
accessdate = 2007-10-19
] . had prepared a rescue mission by the Special Air Service. Troops deployed to the Middle East, including a team in Beirut, but the mission was called off.

1980s Falklands War SIGINT

During the Falklands War ( _es. Guerra de las Malvinas/Guerra del Atlántico Sur) in 1982, Argentina used Boeing 707s, with visual reconnaissance capability only, to surveillance of the British Task Force. These were driven away by British Harriers and missiles, at which point their use was stopped. The experience, however, convinced Argentina that it needed a SIGINT aircraft, and Israel later converted a Argentine 707.Citation
title = The Spyflight Website: Boeing707
date = 1 Jan 2007
url =
accessdate = 2007-10-12

Under the UKUSA Agreement, Great Britain called upon NSA SIGINT satellite resources to collect relevant information. Tension existed because the controversial British investigative journalist, Duncan Campbell, had published information considered sensitive. According to one former British SIGINT officer, "We can ask the Americans to do things, but we cannot compel them. There may be targets they don't want to cover. The Falklands was a factor here. It brought going it alone back into fashion."

Policy and doctrinal evolution

Aside from public multinational activities such as the abortive 1983 Beirut barracks bombing, there were less obvious discussion and negotiation among nations seeking to deal with the immense cost of space-based SIGINT.

1980s French SIGINT policy

Pike wrotePikeFrenchSIGINT] that the Socialist government, elected in May 1981 and led President François Mitterrand were unknown at the time of his election in May 1981 marked the attempt to put SDECE under civilian control. In June 1981, Stone Marion, a civilian who was the former Director of the Paris Airport, was named to the head of the SDECE but met with opposition, as a socialist and civilian, from inside SDECE.

France and Britain had both been facing both the desirability and cost of intelligence satellites independent of the US. In the mid-1980s, with the development of the Ariane launcher and its associated large launch complex in French Guiana, the French liked the idea of such independence. Planning started on French IMINT satellites called Helios, a radar imaging satellite called Osirus and then Horus, and a SIGINT satellite to be called Zenon when operational. France would launch technology demonstrators before a fully operational SIGINT satellite.

1980s United Kingdom SIGINT policy

To obtain some autonomy in SIGINT, while simultaneously strengthening its role in the UKUSA Agreement, Britain planned to launch its own SIGINT satellite, codenamed Zircon. Proposed in 1983 to be in a geosynchronous orbit over the Soviet Union, it was cancelled, principally on grounds of cost, in 1987. Urban stated that Britain did contribute to the cost of one of the NSA MAGNUM SIGINT satellites, possibly having one dedicated to UK use.

After the decision not to develop the independent ZIRCON, the possibility of cooperating with France on space-based intelligence was considered by the Cabinet, along with other discussions with France about co-developing an air-launched nuclear missile. While France might have welcomed the investment, the cost still would be very high for Britain, and the traditional antagonism between France and the UK would have to have been overcome.

According to Urban, by 1987, the UK concluded working with the French was not a real alternative. Perhaps based on experience with the UKUSA Agreement, a British civil servant observed, "Investing anywhere else [than the US] would have bought far less capability. The French don't even know how far behind they are."

1980s United States SIGINT policy and doctrinal evolution

1980s US Strategic SIGINT policy and doctrine

In 1980, U.S. intercepts of Soviet communications generated a fear that the Soviets were about to invade Iran. In 1983 intercepts allowed the United States to piece together the details concerning the sinking of a Soviet submarine in the North Pacific.

In 1983 it began an all-source program targeting Soviet prison camp system, with the specific intent of issuing a study that would embarrass the SovietsRichelson1989>] .

MAGNUM geosynchronous SIGINT satellites were first launched from the Space Shuttle in 1985. These were believed to be more sensitive and perhaps stealthier than RHYOLITE/AQUACADE.

After the Liberty and Pueblo incidents, only combatant ships, destroyers and frigates, were used for collection missions. In addition to SIGINT intercept against the Soviets, combatant ships operated off Nicaragua, El Salvador, and Honduras. One purpose-built SIGINT auxiliary, the ARL-24 Sphinx, generally stayed off the Nicaraguan coast.

1980s US Tactical SIGINT policy and doctrine

After the Beirut deployment, the US Marine Corps did an after-action review of the 2nd Radio Battalion detachment that went with that force. LTG Al Gray, then commanding Fleet Marine Force Atlantic, and LTC Bill Keller, commanding 2nd Radio Battalion, did an after-action review. Part of the reason for this was that the irregular units that presented the greatest threat did not follow conventional military signal operating procedures, and used nonstandard frequencies and callsigns. Without NSA information on these groups, the detachment had to acquire this information from their own resources.

Recognizing that national sources simply might not have information on a given environment, or that they might not make it available to warfighters, LTG Gray directed that a SIGINT function be created that could work with the elite Force Reconnaissance Marines who search out potential enemies. At first, neither the Force Reconnaissance nor Radio Battalion commanders though this was viable, but had orders to follow.

Initially, they attached a single Radio Battalion Marine, with an AN/GRR-8 intercept receiver, to a Force Reconnaissance team during an exercise. A respected Radio Marine, CPL. Kyle O'Malley was sent to the team, without any guidance for what he was to do. The exercise did not demonstrate that a one-man attachment, not Force Recon qualified, was useful.

In 1984, CPT E.L. Gillespie, assigned to the Joint Special Operations Command, was alerted that he was to report to 2nd Radio Battalion, to develop a concept of operations for integrating SIGINT capabilities with Force Recon, using his joint service experience with special operations. Again, the immediate commanders were not enthusiastic.

Nevertheless, a mission statement was drafted: "To conduct limited communications intelligence and specified electronic warfare operations in support of Force Reconnaissance operations during advance force or special operations missions." It was decided that a 6-man SIGINT team, with long/short range independent communications and SIGINT/EW equipment, was the minimum practical unit. It was not practical to attach this to the smallest 4-man Force Recon team.

LTG Gray directed that the unit would be called a Radio Reconnaissance Team (RRT), and that adequate planning and preparation were done for the advance force operations part of the upcoming Exercise Solid Shield-85. Two six-man teams would be formed, from Marines assigned from the Radio Battalion, without great enthusiasm for the assignment. One Marine put it"There is nothing that the Marine Corps can do to me that I can't take." [Citation
author = Jeremy Choate
title = History and Mission [2nd Marine Radio Battalion, Radio Reconnaissance Platoon]
id = 2RRP
year = 2007
url =
accessdate = 2007-10-19
] Force Recon required that the RRT candidates pass their selection course, and, to the surprise of Force Recon, they passed with honors. Both teams were assigned to the exercise, and the RRTs successfully maintained communications connectivity for Force Recon and SEALs, collected meaningful intelligence, disrupted opposing force communications, and were extracted without being compromised.

From 1986 on, RRTs accompanied MEU (SOC) deployments. Their first combat role was in Operation Earnest Will, then Operation Praying Mantis, followed by participation in the 1989 United States invasion of Panama


Terrorism from foreign groups became an increasingly major concern, as with the 1992 al-Qaeda attack in Yemen, the 1993 truck bombing of the World Trade Center, 1995 (Saudi communications center) and 1996 (Khobar Towers) in Saudi Arabia, and the 1998 bombings of the US embassies in Dar es Salaam, Tanzania and Nairobi, Kenya. Third world and non-national groups, with modern communications technology, in many ways are a harder SIGINT target than a nation, such as Russia or China, that sends out large amounts of traffic. According to the retired Commandant of the US Marines, Alfred M. Gray, Jr., some of the significant concerns of these targets are::*Inherently low probability of intercept/detection (LPI/LPD) because off-the-shelf radios can be frequency agile, spread spectrum, and transmit in bursts.:*Additional frequencies, not normally monitored, can be used. These include citizens band, marine (MF, HF, VHF) bands, and higher frequencies for short-range communications:*Extensive use of telephones, almost always digital. Cellular and satellite telephones, while wireless, are challenging to intercept, as is Voice over IP (VoIP):*Commercial strong encryption for voice and data:*"Extremely wide variety and complexity of potential targets, creating a "needle in the haystack" problem" [cite journal
last = Gray
first = Alfred M.
authorlink = Alfred M. Gray, Jr.
title = Global Intelligence Challenges in the 1990s
journal = American Intelligence Journal
pages = 37–41
date = Winter 1989- 1990
url =
accessdate = 2007-10-08 |format=PDF


While Helios was IMINT, not SIGINT, it helped put perspective on program costs. Helios 1A was launched on 07 July 1995 [Citation
author = Federation of American Scientists
title = Helios
id = FAS Helios
url =
accessdate = 2007-10-19
] . The Cerise SIGINT technology demonstrator also was launched in 1995; it is not clear if it was on the Helios 1 launch. A radio propagation experiment, S80-T, was launched in 1992, as a predecessor of the ELINT experiments.

Financial pressures in 1994-1995 caused France to seek Spanish and Italian cooperation for Helios 1 and German contributions to HELIOS 2. HELIOS 2A was launched in 2004. France, still desiring to have three different space-based intelligence systems (IMINT, radar surveillance, SIGINT), had to face extremely high costs. In 1994-1995, French legislators tried to reduce some of these plans. In response, the French government sought Italian and Spanish funding in, and cooperation with, the HELIOS 1 program. They also sought German involvement in Helios 2. The HELIOS 2A launch also was accompanied by a small constellation of ELINT satellites.

The Cerise ELINT technology demonstrator, also launched in 1995, was damaged by a collision with another French payload, SPOT-1, in the following year.

Clementine, the second-generation ELINT technology demonstrator, was launched in 1999.

United Kingdom

Controversy arose over alleged British interception of communications to Ireland from a facility called the Ministry of Defence Electronic Test Facility in a British Nuclear Fuels Limited site at Capenhurst, Cheshire. This facility was in the line of microwave towers from the UK-Ireland 1 cable (Dublin to Anglesey) landing to BT in London. Besides the Capenhurst tower, communications to and from the Irish Republic were also intercepted at a similar but A smaller GCHQ station in County Armagh was said to target links between Dublin and Belfast, and a third station intercepted satellite communications in Cornwall [cite journal
last = Campbell
first = Duncan
coauthors = Paul Lashmar
title = How Britain Eavesdropped on Dublin
journal = American Intelligence Journal
id = Campbell 1999
date = July 16, 1999
url =
accessdate = 2007-10-08
] . Irish politicians, led by former Prime Minister Albert Reynolds, demanded an investigation.


As evidenced by the Hainan Island incident, even while China and the US may cooperate on matters of mutual concern towards Russia, the Cold War has not completely disappeared.

There was more regional cooperation, often driven by concerns about transnational terrorism. European countries also are finding that by sharing the cost, they can acquire SIGINT, IMINT, and MASINT capabilities independent of the US.

In the US, both communications security and COMINT policies have been evolving, some with challenges. The adoption of a Belgian-developed encryption algorithm, approved in a public process, and accepted both for sensitive but unclassified traffic, as well as for classified information sent with NSA-generated and maintained keys, redraws the cryptologic environment as no longer NSA or not-NSA. Controversy continues on various types of COMINT justified as not requiring warrants, under the wartime authority of the President of the United States.

Technologically, there was much greater use of UAVs as SIGINT collection platforms.

Hainan Island incident

In 2001, a US EP-3 SIGINT aircraft had a midair collision with a shadowing Chinese fighter, in what has become known as the Hainan Island incident. Both sides blamed the other, although the US claimed the aircraft was in international airspace, a reasonable assumption given the amount of navigational instrumentation it carries. The fighter pilot died, and the EP-3 made an emergency landing in China, erasing as much sensitive information as possible. While the Chinese did not release the aircraft for several months, the crew having been released earlier, the most sensitive information was not so much the aircraft's instrumentation, but the signals it was targeting and the reference material about the Chinese "electronic order of battle".

European Space Systems cooperation

French initiatives, along with French and Russian satellite launching, have led to cooperative continental European arrangements for intelligence sensors in space. In contrast, the UK has reinforced cooperation under the UKUSA agreement.

French space-based intelligence

On 18 December 2004, [Citation
author = Tariq Malik
title = Ariane 5 Successfully Orbits France's Helios 2A Satellite
id = Malik 2004
date = 18 December 2004
url =
accessdate = 2007-10-19
] HELIOS 2A, built by EADS-Astrium for the French Space Agency (CNES), was launched into a Sun-synchronous polar orbit at an altitude of about 680 kilometers. There it will serve the French defense ministry, as well as cooperating European countries. HELIOS 2B is scheduled for launch in 2008.

The same launcher carried French and Spanish scientific satellites and four Essaim ("Swarm") experimental ELINT satellites [Citation
author = Jonathan McDowell
title = Jonathan's Space Report No. 541: Helios 2
id = McDowell 2004
date = 25 December 2004
url =
accessdate = 2007-10-19
] [Citation
author = Space Daily
title = ESSAIM, Micro-Satellites In Formation
journal = Space Daily
id = ESSAIM 2005
date = July 03, 2005
url =
accessdate = 2007-10-19
] . Sources in the French procurement agency, DGA, confirmed Essaim, a system of ground station and satellite constellation, is working well. [Citation
author = Peter B. de Selding
title = ESSAIM, Micro-Satellites In Formation
journal = Space News Business Report
id = de Selding 2005
date = 21 March 2005
url =
accessdate = 2007-10-19
] . There have been French defense complaints about Essaim being a third technology demonstrator, after the 1995 Cerise and 1999 Clementine. DGA countered that Essaim will demonstrate more advanced technology, important to convince other European governments to help with the cost. Essaim is to provide some operational data. The first of three ground stations is operational, with three satellites in operation and the fourth considered an in-orbit spare.

In a Ministère de la Défense 12/18/2004 statement, France announced [Citation
author = Office of Science and Technology, French Embassy in the US
title = HELIOS IIA: A New Boost for European Defence
journal = Space News Business Report
id = France 2004
date = 18 December 2004 [Ministère de la Défense 12/18/2004, AFP 12/18/2004]
url =
accessdate = 2007-10-19
] that Helios 2A is part of an exchange program planned with the German SAR Lupe and Italian COSMO-SKYMED systems, under development respectively in Germany and Italy.

German Space Systems

Following the first successful launch on December 19, 2006, about a year after the intended launch date, further satellites were launched at roughly six-month intervals, and the entire system of this five-satellite SAR Lupe synthetic aperture radar constellation achieved full operational readiness on 22 July 2008. [ [] Spaceflight now - Radar reconnaissance spacecraft launched] SAR is usually considered a MASINT sensor, but the significance here is that Germany obtains access to French satellite ELINT.

Italian Space Systems

With the first satellite launched on June 8, 2007, [Citation
author = William Atkins
title = Italian COSMO-SkyMed satellite launched to study world’s weather
journal = ITwire
id = Atkins 2007
date = June 9, 2007
url =
accessdate = 2007-10-19
] Italy and France are cooperating on the deployment of the dual-use Orfeo civilian and military satellite system [Citation
author =
title = Successful Launch Second German Sar-Lupe Observation Satellite
id = Deagel 2007
date = October 19, 2007
url =
accessdate = 2007-10-19
] .

Orfeo is a dual-use (civilian and military) earth observation satellite network developed jointly between France and Italy. Italy is developing the Cosmo-Skymed X-band polarimetric SAR, to fly on two of the satellites. The other two will have complementary French electro-optical payloads. The second Orfeo is scheduled to launch in early 2008.

While this is not an explicit SIGINT system, the French-Italian cooperation may suggest that Italy can get data from the French Essaim ELINT microsatellites.

Acceptance of cryptologic expertise outside NSA

The US government withdrew the last approvals for the Data Encryption Standard, approved for unclassified use in 1976 but now considered quite vulnerable. Its replacement, the Advanced Encryption Standard (AES) was approved in 2002. AES, when used with NSA-supplied keys, is approved for TOP SECRET traffic as well as unclassified, and may be considered a reference point for strong commercial encryption. AES appears, at the present time, to be secure when used properly, which represents a major change in US policy about the availability of strong communications security. Not all governments will allow the use of such strong ciphers.

That the algorithm chosen came from Europe points to a more multilateral world with respect to communications security. AES was developed by two Belgian cryptographers, Joan Daemen and Vincent Rijmen, and submitted to the AES selection process under the name "Rijndael", a portmanteau of the names of the inventors.

Terrorism and response in the US

As a result of the 9/11 attacks, intensification of US intelligence efforts, domestic and foreign, were to be expected. A key question, of course, was whether US intelligence could have prevented or mitigated the attacks, and how it might prevent future attacks. It should be noncontroversial that there will be a delicate balance of intelligence and civil liberties issues.

IGINT and the 9/11 attacks

In a statement to a joint meeting of the House and Senate Intelligence Committees, NSA Director LTG Michael Hayden said "NSA had no SIGINT suggesting that al-Qa'ida was specifically targeting New York and Washington, D.C., or even that it was planning an attack on U.S. soil. Indeed, NSA had no knowledge before September 11 that any of the attackers were in the United States....

"We are digging out of a deep hole. NSA downsized about one-third of its manpower and about the same proportion of its budget in the decade of the 1990s. That is the same decade when packetized communications (the e-communications we have all become familiar with) surpassed traditional communications. That is the same decade when mobile cell phones increased from 16 million to 741 million an increase of nearly 50 times. That is the same decade when Internet users went from about 4 million to 361 million an increase of over 90 times. Half as many landlines were laid in the last six years of the 1990s as in the whole previous history of the world. In that same decade of the 1990s, international telephone traffic went from 38 billion minutes to over 100 billion. This year, the world's population will spend over 180 billion minutes on the phone in international calls alone.

"throughout the summer of 2001 we had more than 30 warnings that something was imminent. We dutifully reported these, yet none of these subsequently correlated with terrorist attacks. The concept of "imminent" to our adversaries is relative; it can mean soon or imply sometime in the future"Citation
last = Joint Hearings of the US House and Senate Intelligence Committees
title = Statement of LTG Michael V. Hayden, Director, National Security Agency
date = 17 October 2002
year = 2002
url =
accessdate = 2007-10-12

US domestic surveillance issues

Under the George W. Bush administration, there has been a large-scale and controversial capture and analysis of domestic and international telephone calls, claimed to be targeted against terrorism. It is generally accepted that warrants have not been obtained for this activity, sometimes called Room 641A after a location, in San Francisco, where AT&T provides NSA access. While very little is known about this system, it may be focused more on the signaling channel and Call detail records than the actual content of conversations.

Another possibility is the use of software tools that do high-performance deep packet inspection. According to the marketing VP of Narus, "Narus has little control over how its products are used after they're sold. For example, although its lawful-intercept application has a sophisticated system for making sure the surveillance complies with the terms of a warrant, it's up to the operator whether to type those terms into the system...

"That legal eavesdropping application was launched in February 2005, well after whistle-blower Klein allegedly learned that AT&T was installing Narus boxes in secure, NSA-controlled rooms in switching centers around the country. But that doesn't mean the government couldn't write its own code to do the dirty work. Narus even offers software-development kits to customers ".Citation
last = Singel
first = Ryan
title = Whistle-Blower Outs NSA Spy Room
journal = Wired
date = 04.07.06
year = 2006
url =
id = ATTWired
accessdate = 2007-10-08
] The same type of tools with legitimate ISP security applications also have COMINT interception and analysis capability.

Former AT&T technician Mark Klein, who revealed AT&T was giving NSA access, said in a statement, said a Narus STA 6400 was in the NSA room to which AT&T allegedly copied traffic. The Narus device was "known to be used particularly by government intelligence agencies because of its ability to sift through large amounts of data looking for preprogrammed targets."


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