There were many wars occurring simultaneously during the conflict in Southeast Asia. In some cases, the rivalries that existed—between front-line infantry and support troops helping to keep them in the field—hinged precisely upon ignorance of the others’ real contribution to the war effort. The war of the line-doggies, of the bombers, and of the big battalions was obvious. A level beneath that was the secret war of covert operations. There was another war, too, even more secret than the covert one, a war of radio waves that took place entirely in the air, where the victories and defeats were gained by men and women hunched over hot electronic components or tables of figures and charts. For a time, at the dawn of the war, there were even senior policymakers who believed the combatants in this war would decide the victors in the baffles of the bombers and the big battalions. This is the story of the spooks in the ether.
One mainstay of the French war in Vietnam had been their Radio Technical Service, a unit that, despite its name, had nothing to do with radio technical support other than that it used the air waves to intercept Vietminh communications. The French had broken the Vietminh logistics code and other operational codes at various times during the first Indochina war. One of the reasons for French overconfidence heading into the battle of Dien Bien Phu had been precisely that their intelligence would know everything the adversary was doing. Things did not work out that way, of course; it was the French who were ultimately defeated and were forced to leave Vietnam. They took their communications intelligence organization with them, including most of its equipment.
The infant Army of the Republic of Vietnam (ARVN) had grown from French colonial roots and was well aware of the capability the radio service had provided to the French Expeditionary Corps. Nevertheless, they began with nothing more than three old, cranky, and hard-to-fix radio direction finder (RDF) units. In April 1957, the Vietnamese created their own radio intelligence service -- called the Technical Study Center--which was commanded by a lieutenant, had just 65 people assigned to it, and opened radio listening posts at Saigon and Danang.
President Ngo Dinh Diem followed up in 1958 by asking for U.S. assistance for its radio intelligence efforts. Dwight D. Eisenhower responded in the negative because Washington feared compromise of the top-secret code-breaking techniques of its National Security Agency (NSA).
Diem renewed his request in early 1960 when he sent an emissary to a political officer at the U.S. Embassy. This time, he asked for little more than equipment. That August, the U.S. replied in the affirmative. The war in the ether had just escalated a rachet.
When John Kennedy took office, the communications intelligence program (COMINT) was little further along than the previous summer. President Kennedy was looking for ways to galvanize the South Vietnamese, and one of the recognized problems the ARVN had was poor combat intelligence. A sophisticated COMINT capability might well be the answer, or at least part of it. The idea this time was not just U.S. equipment but an actual American COMINT unit. The idea was one of the recommendations considered by a panel of senior policymakers headed by Secretary of Defense Gilpatric. The Gilpatric group reported on April 27, 1961, and two days later, Kennedy discussed its recommendations with his senior advisers on the National Security Council. He approved the program, including the proposed COMINT unit, which also comprised Green Berets and the Air Force "Jungle Jim" unit, and gave a directive that there be no public acknowledgement of any part of it. Apparently, because of its top-secret treatment, the Gilpatric committee program received its formal approval in a memorandum from Secretary of Defense Robert S. McNamara; it was never consecrated by a National Security Council directive.
The Gilpatric committee program led swiffly to consideration of a Vietnam move at the United States Intelligence Board (USIB). The board, then headed by Allen W. Dulles, was the top authority over all American intelligence pro-grains, and USIB had previously been a key obstacle preventing provision of COMINT assistance to South Vietnam. This time, the USIB approved two new projects, code-named Whitebirch and Sabertooth; one was to provide Vietnam with help on communications intelligence, the other communications security (COMSEC). Whitebirch was authorized three officers and seventy-four enlisted men; Sabertooth one officer, two warrant officers, and a dozen men. The unit arrived at Saigon, where it was constituted as the 400th Operations Unit (Provisional) of the U.S. Army Security Agency, with the cover identity of Third Radio Research Unit (RRU). The code-breakers set up shop in a heavily guarded compound at Tan Son Nhut airfield.
Not long afterwards, a member of the Third RRU became the first American soldier killed in action in South Vietnam. On December 22, 1961, Sp4. James T. Davis was with an ARVN mobile radio direction-finding team that was ambushed by Vietcong. Davis’ trick was blown off the road by a mine. The American and his ARVN companions were then finished off by the ambushers. Getting the drop on the Vietcong turned out to be a lot tougher than anyone imagined. Augmentation of the Third RRU followed, and, in January 1962, it was authorized to expand to 25 officers and warrants and to 358 enlisted personneL The real problem, as the American code-breakers were not yet aware, was that there was not a lot of Vietcong radio traffic to intercept For example, the key North Vietnamese intelligence organization, called the Research Bureau,maintained its agent networks in the South with minimal use of radios. There were radios assigned to the nets, but, for the most part, these were simple transistor radios, such as Japanese models that could be bought anywhere. The operators’ only function was to listen to Hanoi broadcasts at certain times and dates and to copy down Morse code messages to be passed along to the agents, who would know their meanings. The agents’ own messages were given to couriers, preventing the network from ever being compromised by radio transmissions. Only in a dire emergency or with a highly urgent message would Research Bureau nets actually broadcast messages, and then they would pass these along to operators of a few clandestine transmitters maintained in South Vietnam for this purpose.
These kinds of organizational security measures to a great extent made up for Hanoi’s inability to protect its radio traffic by sophisticated equipment or codes. In both these departments, North Vietnamese and Vietcong capabilities were strictly limited. For example, although the North Vietnamese Army (NVA) maintains it was created as early as 1944, was active in 1945. and had fought against the French beginning in December 1947, it was not until June 1950 that the merger of smaller units created the NVA General Staff Cryptographic Bureau. The codes used were standardized only within relatively small entities, such as regions or single army divisions, and all were substitution codes. Some of the better ones split words in two, three, or four parts for more involved encoding, but there was nothing like the machine encryption devices common in the U.S. military, and there would not be such sophistication in Hanoi’s methods throughout the war with the Americans.
The basic code used in the early 1960s was a development innovated by the Cryptographic Bureau as early as 1951. Similarly, radio equipment was a hodgepodge of French, Chinese, Russian, Japanese, and American material—hard to keep spare parts for and relatively primitive. Channel-switching, frequency seekers, and secure voice devices were unknown to North Vietnamese practice until late in the American war when military aid and stealing of American equipment made more advanced radios available.
The North Vietnamese were wise to focus on the kinds of security measures they could safely implement One was their careful separation of communications personnel, not only from agents but also from encoding and decoding personnel. The various specialists were not only separated on duty, they were forbidden to associate when not working. In May 1961, Hanoi sent two infiltration groups into the South composed entirely of code cadres; their move to increase COMSEC matched the American commitment of a new communications intelligence unit.
The U.S. had a capability to increase its COMINT effort more rapidly than had North Vietnam. The increase was certainly visible in terms of personnel and units. By June 1964—just before the incidents in the Gulf of Tonkin—the Third RRU was fielding 43 officers and 543 enlisted men. There was also an independent Detachment J of the RRU with another 270 officers and men and 10 Vietnamese personnel; a detachment of the Marines’ First Composite Radio Company with 48 officers and men; and the Seventh RRU, committed in September 1962, with another 37 personnel. Given that the North Vietnamese committed two communications battalions to operate their entire radio net along the Ho Chi Minh Trail, the Americans working against NVA communications at that time—strictly an offensive intelligence mission—must have matched rather closely the strength of the entire opposing organization.
In the meantime, the South Vietnamese were building their own radio intelligence capacity. In 1963, the offensive radio effort, COMINT, was concentrated in an entity called Unit 15, and the so-called First Radio Control Unit was formed to handle COMSEC. Continuing problems existed; the ARVN units were forced to compete for scarce radio operators with all other South Vietnamese communications users, and, unlike American practice, ARVN radio intelligence operators were not awarded extra pay[say what?..what extra pay?-md] or given any other distinction[still waiting for my teal blue beret!]. Moreover, there was competition for limited amounts of equipment. Nevertheless, there was progress, and Unit 15 went into the field in October 1962, with forward bases at Danang, Nha Trang, Pleiku, and Ban Me Thuot.
Despite growth pains and drawbacks, commumcations intelligence scored some real successes. Gen. Nguyen Khanh recounts that, in early 1964, his radio intelligence, presumably Unit 15, was able to establish the location of a key Vietcong command post—it may have been the headquarters of Military Region 5. General Khanh mounted a lightning operation, dropping ARVN paratroops on the site and surprising the Vietcong, most of whom barely had time to escape. The South Vietnamese seized the command’s senior doctor. More important, they captured a radio set and a complete set of code charts. The Vietnamese photographed this material, then left it exactiy as it appeared, hoping the Vietcong would think ARVN had missed this installation. The VC reportedly went on using those codes for months.
North Vietnamese sources do not admit that any attack took place on the Military Region 5 headquarters; they do concede an attack occurred about this time on a school teaching cryptography. Another emergency evacuation of a cryptographic school for security reasons would occur in 1966.
According to General Khanh, the occupants of the headquarters at the time ARVN forces attacked it had included North Vietnamese senior officer Bui Tin, who would go into exile after the war to protest Hanoi’s policies. Tin reportedly told Khanh he and other top officers, including the region commander, had to run away in their underpants.
North Vietnam, still dependent upon primitive communications networks, actually created certain problems for the would-be COMINT mavens among the Americans and South Vietnamese. Seven thousand miles of French open-wire telephone lines predominated, and there was an old civil radio net By this point in the war, foreign aid had yielded little more than some radio-telegraph equipment used by Communist Party, military, and police units and a 3,000-line automatic telephone switchboard promptly installed at Hanoi. The phone lines did not produce emissions that could be intercepted at long range. This became an advantage in tactical combat in the South when NVA forces used only runners and telephones for their unit-level tactical nets. Radio served only to communicate with higher headquarters, and those contacts were made strictly upon a time-and-frequency schedule, after which transmitters would again go silent.
These techmques severely limited the volume of traffic accessible to American COMINT receivers, although "limited" is a relative term. In 1965, for example, an average of 200 messages were handled daily by the headquarters of North Vietnamese Military Region 4, which covered the "panhandle" area just above the demilitarized zone. In addition, as North Vietnamese and Vietcong troop levels rose, the need for rapid communication, faster than that possible by courier or telephone, grew enormously. By 1966, Hanoi perceived enough of a problem with the security of its own communications that the General Staff issued a special directive setting COMSEC standards. The Army also held a conference of cryptographic experts in an effort to improve the security program. That year, the General Staff handled 1,982,225 secret messages; Military Region 4 sent or received another 274,708. Clearly, there was a potential for compromise of secret information.
What was true for the North Vietnamese was so in spades for the Americans, who were used to radio at every level and for virtually every purpose, and who had radio transmitters much more widely distributed among their forces than the NVA. As a test of friendly COMSEC, the Seventh RRU furnished a monitoring team that augmented the radio research company assigned to the First Cavalry Division (Airmobile) soon after that unit arrived in South Vietnam. The idea was to listen in on friendly transmissions and to see how much the Vietcong or NVA could have learned from them. The radiomen monitored 10,902 transmissions over a three-week period as the Cav made its initial deployments. They found transmitters had little concern for security precautions; they were compromising net frequencies and call signs by sending them in the clear and rarely used preplanned authentication systems.
The COMSEC specialists recommended improvements, but shortly afterwards, the First Cavalry became embroiled in the fierce battle of the Ia Drang Valley. During that engagement, COMSEC teams listened to 28,023 more radio transmissions. They found that security was almost never used. were unauthorized, homemade ones easily broken by the NVA; actual Army codes and encryption devices were never used in practice. The Ia Drang battle alarmed National Security Agency officials and impelled the NSA and milltary contractors to design new equipment to scramble the sound of a voice on the radio, the so-called "secure voice transmission."
These kinds of lapses made it easy for North Vietnamese and Vietcong operators to pick up detailed pictures of the opposing forces and data on upcoming attacks. They even endowed them with an ability to come up on American radio nets with false messages, calling off attacks or artillery bombardments. When the First Cavalry signals officer tried to change all the division’s radio call signs in the midst of the battle to restore security, the attempt caused so much confusion among Cav units, the change was called off to restore combat effectiveness.
Both sides could play at the radio deception game, as Maj. Gen. William E. DePuy’s First Infantry Division showed north of Saigon in the summer of 1966. DePuy’s intelligence officer had initiated an effort to achieve close coordination with the RRU supporting the division, in this case the 337th Army Security Agency (USASA) Company (sic) [actually called 337th Radio Research Company while in RVN-md]. Learning that the opposing VC Ninth Division was on the move, DePuy had messages sent on the radio claiming a weak troop of armored cavalry would be on the Minh Thanh Road at a certain time. In actuality, four infantry battalions with plenty of artillery were poised to spring a trap. The resulting battle of the Minh Thanh Road in July 1966 ended with over 300 dead Vietcong.
North Vietnamese interception efforts were hampered at first because of their primitive radio equipment—at one point, more than two dozen different types of radios were being used in field units—equipment not very compatible with the AN/PRC-25 radios employed by American tactical communications nets. Here, VC agents came in handy, stealing PRC-25 sets whenever possible in South Vietnam. First priority went to North Vietnamese COMINT units, but, by 1969,. the NVA had captured so many PRC-25 sets that the equipment was becoming Standard in North Vietnamese combat units. The Americans then introduced the AN/PRC-77, the long-awaited secure voice radio. Deception was common throughout this period. For example, NVA were entering U.S. or South Vietnamese radio nets with deceptive imitation messages, in the northernmost provinces alone, averaging ten a month during the first four months of 1967.
The American radio spooks inaugurated a new effort to permit instant tactical exploitation of intercepted messages, an attempt to repeat successes like that on the Minh Thanh Road. The program was termed Project Dancer, and it involved putting Vietnamese nationals to work alongside the radio operators to supply instant translations that could be passed to field units as intelligence. Later, Project Dancer would expand to the air, and Vietnamese would fly planes with American intercept operators. Dancer involved significant security risks because the Vietnamese, if they were VC spies, would be getting extremely close to some of the most highly secret equipment and techniques imaginable. Extra precautions taken to enhance security, like investigating recruits and isolating their working spaces, retarded expansion of the program and slowed down the rate at which intelligence could be sent down to combat forces.
Thomas Ferguson, an intelligence officer with the Twenty-fifth Infantry Division, which worked with the 372nd USASA Company (sic) at Cu Chi, complained that Saigon’s review ("sanitization") of data collected this way robbed it of timeliness. Ferguson also made the point that, with the number of troops Cu Chi could send into the field and with the small size of typical VC units, the Vietcong usually only had to move a half mile or so before a sweep operation would miss them. Moves of that length could be made in the time necessary for a message to be sent from Cu Chi to Saigon and back, without counting what the 509th USASA Operations Group,(sic) the overall COMINT command, would need to decide how to reply.
Radio intercepts revealed some of these troop movements and helped clue in Gen. William Westmoreland to the NVA maneuvers. It is too much to assert, however, as it is sometimes claimed, that COMINT predicted the Tet Offensive.[not what Ive heard from every single ASAVeteran who was in country at the time.now if that info got to the right people and if they acted on it is a different story, I have yet to talk to any ASA who did not know that Tet 68 was on its way,so I dont know what the author bases this statement on.. His personel feelings?-md]. Rather, the radio spooks added data that helped Westmoreland fix his focus upon Khe Sanh.
As intercepts indicated threats to other South Vietnamese targets, particularly the cities and towns, the intelligence predictions shifted only to something that might be called "Khe Sanh-Plus," not to any expectation of a countrywide offensive without Khe Sanh. A report that the National Security Agency circulated on January 25, 1968, is said to have wamed that points throughout South Vietnam were threatened. However, a member of the CIA’s Office of the Special Assistant for Vietnam Affairs who saw this report construes it differently. Agreeing the NSA report observed an "almost unprecedented volume of urgent messages ... passing among major commands," the CIA officer notes the document merely termed as "possible related activity" what it could pick up in the area of Saigon and southernmost South Vietnam. This hardly constitutes explicit prediction of Tet.[in fact even the most rookie traffic analyst would know that a big jump in traffic means a big op is on the way-md]
When the Tet attacks began, with intensity seldom before seen in the war. The radio spooks did not escape North Vietnamese attention. At Phu Bai—the location of the 1,076-man-strong Eighth RRU—the radio intelligence compound was the target of a rocket bombardment late in the afternoon, just before the main attacks, apparently an attempt to short-circuit COMINT observation of NVA activity during the offensive. Fifteen heavy rockets hit the compound, but they missed all the key targets. Instead, the rockets demolished the bachelor officers quarters, but no one was hurt.[So apparently even if the author makes light of ASA contributions, apparently the NVA did not. For some reason, the authors ‘conclusions’ just dont seem to fit with the ‘evidence’ he relates in the article md]
Tet was also the occasion for acts that resulted in the award of a Legion of Merit to Pfc. Edward W. Minnock Jr., who became the only enlisted soldier ever given this honor. Minnock was an analyst of COMINT intercepts with the 404th Radio Research Detachment, working alongside the 173rd Airborne Brigade in central Vietnam. Having previously supplied valuable intelligence during the November 1967 battle of Dak To, Minnock this time helped in the defense of An Khe and Tuy Hoa. Several months later, he explicitly warned of a planned NVA attack against Thy Hoa in time for it to be broken up in defeat.[see what I mean?-md]
There could be no doubt that managing the many activities of Tet forced the North Vietnamese to unprecedented levels of radio traffic. One Hanoi publication notes the number of messages handled by the General Staff Cryptologic Directorate increased from the previous average of 5,000 per month to a new peak of 13,000. With all those messages, there was more to intercept and more possibilities for radio direction finding (RDF).[I dont know What the authors background is..but anybody who did this for a living wouldnt have to break all the codes or be a rocket scientist to predict Tet 68 JUST from what is said In the above paragraph—big time traffic, all over the spectrum=big time operation, plain and simple-md]
At the height of this period when, just before Tet proper, Westmoreland thought he was fighting a battle of Khe Sanh, the RDF specialists tentatively identified a senior NVA headquarters in Laos. Some insisted it was the main NVA command and Gen. Vo Nguyen Giap himself was there (certain intercepts apparently indicated Giap had left Hanoi for the South). Westmoreland had the cave location plastered by a massive B-52 raid—almost nine hundred tons of bombs dropped in two waves. Though several accounts date this raid on January 29, 1968, Westmoreland actually reported its results to Ambassador Ellsworth Bunker at a meeting on January 24. In any case, Giap was not at the command center, and the bombing did not stop Tet. After 1968, however, North Vietnamese practice ensured significant separation between a communications unit and the command post it served.
Harve Saal, a field man with MACV’s Studies and Observation Group (MACVSOG), reports his covert unit [ 403d SOD—101st RRC??-md] had great success listening in on North Vietnamese radio nets, so much so that troops would joke that going on actual missions was unnecessary [huh?-md] At the same time, the MACV/SOG men grumbled that the NVA always seemed to be able to pick up on their patrols virtually as soon as these landed from helicopters.[according to Maj. John Plasters book, "SOG" this problem was partially solved by the 101st RRC doing a study on the MACV/SOG communications practices combined with a policy of sending out ‘reports’ that would be going to ARVN ‘allies’ with incorrect info as regards map coordinates-md] In May 1970, ARVN Rangers in Kontum Province recovered from enemy bodies copies of key codes (one-time pads) of a type used by MACVSOG, with date markings on certain pages suggesting they could recover any traffic they held for those days.
The Americans and South Vietnamese mounted a special effort against North Vietnamese communications intelligence during 1969. By then, adversary COMINT was evaluated as a major impediment to combat operations. A Pacific Command study of operational security that spring estimated the NVA and VC might have as many as 4,000 persons just working to break into friendly communications. Some suspected the number was as high as 5,000.
The North Vietnamese enjoyed success as well—documents captured in July 1969 included worksheets showing solutions for a number of recovered groups in a widely used U.S. field code and no fewer than fifteen solved ARVN three-digit codes. That December, an infantry platoon of the First Brigade, First Infantry Division, overran a Vietcong radio intelligence unit called "A3" and captured a dozen VC code-breakers and their equipment and documents. Project Touchdown was then inaugurated as an intense effort to get the most knowledge possible of the adversary COMINT effort. The Vietcong proved to have extensive experience, had copied more than 2,000 American or ARVN field radio conversations, and had broken codes; in short, they were thoroughly professional.
The war of the ether briefly became a public issue in 1970 at the time of the American-South Vietnamese invasion of Cambodia As part of the White House’s justification for that operation, Richard Nixon told the American people the armies were going after the Vietcong high command, known as COSVN—the Central Office for South Vietnam. But COSVN was not to be found. As had been the case with tactical information in Project Dancer, the intelligence was dated before it could be put to use. Fomer Vietcong official Nguyen Nhu Thang confirms that COSVN had at one time been in the area the Americans suspected, but it had begun moving away long before the invasion started.
Attempts to track COSVN by radio direction finding were also frustrated by more sophisticated Vietcong operating techniques; the several radio units that worked for COSVN took turns handling the messages, and while one unit worked the radios, all the others would be moving. Thus, Vietcong radio traffic constantly emanated from new locations and could not be used as valid data for the location of COSVN headquarters itself.
Vietnamization affected the radio intelligence war quickly. The Army Security Agency thinned out its units at an early stage, though most of the radio research units only pulled out of South Vietnam in 1971 or 1972. By that time, ARVN and the South Vietnamese Air Force were supplying 95 percent of the intelligence from radio interception. Although the flow continued to be voluminous, the quality of COMINT gathering was diminishing.
In 1969, the North Vietnamese held another armywide conference on improving communications security, and they moved to a new system of general codes. It took time for the Americans and South Vietnamese to regain their former degree of understanding of the NVA codes while their resources were being reduced by withdrawals from Vietnam.
Ultimately, Americans could not win the war of the ether—COMINT did not bring victory in Cambodia in 1970, or in Laos in 1971, and it did not predict the massive Easter Offensive the North Vietnamese launched in 1972. Communications intelligence became ,one more supposed path to victory in Vietnam that merely terminated in a dead end [I dont think I have to say what I think of this statement .See my earlier remarks about the content of this article vs the authors ‘conclusions’ NOTHING could have been done to 'win' the war in Vietnam..politics and Geography made that an impossibility-md]