BUILDUP, 1962 - 1965


Background and Beginnings of

Communications, 1962 - 1964

In 1962 U.S. Army Signalmen in South Vietnam began operating tropospheric scatter radio relay sets capable of providing numerous voice communications channels over extended ranges-the first use of that type of advanced equipment in a combat environment. By 1964, seven years after the Soviet Union had launched the world's first orbiting satellite, US Army Signalmen were operating a new satellite ground station which provided communications service between Saigon and Hawaii through a single communications satellite thousands of miles aloft-the first use of satellite communications in combat. And by 1968 US Signalmen in South Vietnam had begun to operate fully automatic digital message and data switches, another first in a combat zone. These events give some indication of the growth of Army communications during the Vietnam conflict. Any account of communications in Vietnam must include the increasing sophistication in equipment used to meet ever-growing communications needs in support of a multination effort directed toward the dual roles of nation-building and combat. Such an account must also tell the story of the dedicated, highly skilled soldiers who fought the enemy and maintained and operated that equipment in a hot, humid, underdeveloped land thousands of miles from their homes.

The Vietnam Environment

The Republic of Vietnam, located on the eastern portion of the Southeast Asia mainland, lies entirely within the tropics. (Map 1) The terrain is varied, with the large Mekong River Delta in the south, and alternating mountainous and highland areas in the north edging a narrow coastal plain along the South China Sea. Politically, the Republic of Vietnam is divided onto forty-four provinces, which are equivalent to the fifty states of the United States. In turn, each province is made up of districts, comparable to US counties.


Map 1: Republic of Vietnam


The weather has annual variations, from a wet, humid monsoon season to a dry season with practically no precipitation. The terrain and tropical climate have had significant effect on the US

Army's combat communications operations in Vietnam. In the Me-


kong Delta, for example, it was difficult to locate terrain suitable for the placement of communications facilities since most of the area is paddy land, which is partially submerged by the Mekong River during the rainy season, and those areas that are a few feet above water level are densely inhabited. Because of the flat terrain in the delta, tall towers reaching up to 200 feet or more were required to raise antennas to a communicable height. The muddy, silty delta lands provided a poor base for such construction. In the sparsely populated highlands and mountains, sites that afforded both feasible communications paths and reasonable access were rare. Some sites that were selected required extensive preparation, and installations were difficult to build, supply, and defend. As communications equipment became more and more sophisticated, the effects of humidity, dust, and mud were harder to overcome.

During 1959 insurgents in South Vietnam backed by the North Vietnamese were increasing their campaign of violence and subversion in an effort to obtain political control over all Vietnam. In 1960 the Communist Party of North Vietnam decided that South Vietnam was to be "liberated" and unified with the north. Subsequently, Hanoi organized a National Liberation Front and claimed that it was made up of "several political parties" in South Vietnam, with a People's Revolutionary Party identified as the leader. By 1961 the South Vietnamese Communists, termed Viet Cong or VC, were conducting, in addition to their terrorist campaign, military operations of multibattalion size in South Vietnam. The South Vietnamese Government, although it had been receiving US civil and military assistance since 1954, could not cope with the worsening situation.

In late 1961, therefore, South Vietnam urgently appealed for immediate and extensive help from the United States. The US Government decided to expand its assistance to South Vietnam and increased the number of US military advisers from 700 to more than 3,400. Tactical aircraft and Army helicopter units were sent to Vietnam to support and train the South Vietnamese. To keep pace with the growing US commitment, communications in South Vietnam required tremendous expansion.

In February 1962 the United States Military Assistance Command, Vietnam, a US joint headquarters, was established to control the expanding US effort and was made responsible for all US military policy, operations, and assistance in South Vietnam. By that time there were over 3,000 US troops in the country, advising and supporting the South Vietnamese regular military and paramilitary forces.


Communications Background and Initial Buildup

As early as 1951, US Army Signal troops were providing a small US advisory group in Vietnam with communications that linked into the Army's worldwide network. By the time the US Military Assistance Command, Vietnam, was established, high-frequency radio circuits operated by the Strategic Army Communications station in Vietnam were providing communications from Saigon to San Miguel in the Philippines, to Fort Bucknera large Army logistics base in Okinawa-and to Bang Pla near Bangkok in Thailand. These radio links provided a few telephone and message circuits. In addition to its high-frequency radios, the station operated an overseas telephone switchboard and the manual message relay in Saigon. At this time messages were relayed manually at a teletypewriter relay station by taking an incoming message off the receiving equipment in the form of punched tape and inserting the same tape at the appropriate send positions to transmit the message on to its destination.

The advisers, scattered up and down the more than 500-mile­long country, had to rely meanwhile on the low-capacity Vietnamese military communications networks and on a high-frequency radio network they operated themselves to pass messages and furnish telephone service. The Vietnamese commercial system was of little use since it consisted primarily of a few high-frequency radio links using old French equipment. The US Agency for International Development, however, was planning the construction of a major long-lines microwave system to connect Saigon with commercial grade service throughout the country and to include local cable distribution systems.

As the US effort expanded in Vietnam, the very limited communications available could not support the US helicopter units, tactical aircraft, and additional advisers being deployed throughout the land. During 1961 and 1962 the joint staff of the Commander in Chief, Pacific, pushed to modernize the communications facilities in the Republic of Vietnam with two objectives: first, to create a communications system to meet the defense needs of the South Vietnamese in their counterinsurgency operations, and, second, to build it in such a way that it could be expanded to furnish the minimum needs in support of US forces.

Modern radio facilities were supplied through the US Military Assistance Program to improve the South Vietnamese Army's communications system. These radios provided voice and message circuits from Saigon to the outer-province cities of Da Nang, Qui Nhon, Nha Trang, Pleiku, Ban Me Thuot, and Can Tho, and sup-


Photograph: U.S Army Signalman and Vietnamese Installing a Hamlet Radio System


plemented the existing Vietnamese military high-frequency voice and morse code systems. The South Vietnamese Navy received similar radio equipment. A limited tactical air-control system which employed the integrated communications-electronics assets of the US Air Force and the Republic of Vietnam was put into operation. The US Military Assistance Program also supplied radio equipment to connect South Vietnamese hamlets and villages with their district headquarters, to link the district headquarters with patrols and Civil Guard posts within the district, and to connect the districts with their higher province headquarters. Province and district headquarters were also linked into the military communications networks by radio.

Long-Lines Systems: Back Porch

The increased tempo of counterinsurgency operations in Vietnam and the buildup of US assistance to the Vietnamese had created an urgent requirement for a modern, reliable, large-capacity communications system that could provide high quality telephone


Photograph: Tropospheric Scatter and Line-of-Sight Communications


and message circuits between key locations in Vietnam. In early January 1962 Secretary of Defense Robert S. McNamara approved the establishment of a "backbone" communications system to satisfy this need. The system, code-named BACK PORCH, as conceived by planners in Washington and at the headquarters of the Commander in Chief, Pacific, would utilize tropospheric scatter radio trunks capable of providing numerous circuits between locations more than 200 miles apart. These tropospheric scatter trunks would be advantageous since, unlike conventional microwave, which needs a line of sight between sets, they would pass over the vast distances of underpopulated, enemy-infested terrain to connect the major operations and population centers in the Republic of Vietnam north of Saigon. Line-of-sight microwave relay links are limited to much shorter distances, averaging about twenty to thirty miles. From Saigon south to the delta region, long-lines service would be provided by a commercial microwave system, called SOUTHERN TOLL, funded by the US Agency for International Development.

The US Air Force was charged with responsibility for funding and building the BACK PORCH system; the Army would operate the system after its completion. A US Army Signal support battalion, suitably structured for its special mission, was approved for deploy-


Photograph: Billboard Antennas of the Back Porch System at Phu Lam in 1962


On top of the 60-foot tropospheric scatter antennas are the smaller antennas for mobile combat equipment that provided the "tails," or extensions.

ment to Vietnam to operate the BACK PORCH system. It would also operate shorter range "tails," or extensions, serving scattered users, and provide service such as telephone and message communications for the US forces supporting the Vietnamese. In addition, the battalion would give communications support and training to South Vietnamese armed forces.

In January 1962 the US Air Force awarded a contract to furnish and install BACK PORCH. The system would consist of vans containing tropospheric scatter terminals capable of transmitting and receiving up to seventy-two voice channels simultaneously. The links of the system would extend from the Army's Saigon station at Phu Lam to Nha Trang; from Nha Trang to Qui Nhon; from Qui Nhon to DA Nang in the north; from Nha Trang to Pleiku in the Central Highlands; and west from Pleiku to a terminal in Ubon, Thailand. (See Map 2.)

Although these large tropospheric scatter terminals, each of which was mounted in three large semitrailers, were designed for transportable operation, their 30-foot mobile antennas could not be used because of the relatively great path lengths. More effective


and permanent were the 60-foot antennas, set in concrete and resembling billboards, that were constructed instead. The system began service in September 1962 when the BACK PORCH link between Saigon and Nha Trang was activated. At the same time the US Army's 39th Signal Battalion, headquartered at Tan Son Nhut, assumed responsibility for the operation of the system even though it had not been fully tested and accepted.

The 39th Signal Battalion

The 39th Signal Battalion commanded by Lieutenant Colonel Lotus B. Blackwell began to reach Vietnam in February 1962, and by midsummer the entire battalion had arrived. It had an authorized strength of over 1,000 men, consisting of a headquarters detachment and three numbered companies. The mission of the battalion was to operate and maintain the BACK PORCH system; the extensions, or tails, to the backbone system, using mobile teams and equipment; all telephone switchboard exchanges; and communications message centers in the country at that time. The 39th Signal Battalion was also responsible for telephone directory and information service; photographic service, including film and equipment exchange; motor and air courier message service; cryptographic distribution service and maintenance support for all US Army and South Vietnamese units in Vietnam; signal maintenance support; and operation of the US Army Signal Supply Point. The battalion was assigned to the US Army Support Group, Vietnam, which, as the Army component command in Vietnam, came under the operational control of Lieutenant General Paul D. Harkins, the senior commander in Vietnam.

As the elements of the battalion arrived, they were immediately committed, installing and operating communications services for all US forces in Vietnam. The 232d Signal Company was deployed in the Saigon and Mekong Delta areas to provide communications support to all the forces located there. That support included operation of manual telephone exchanges, message communications centers, high-frequency radio teletype and voice terminals, and tails of the backbone system. The 178th Signal Company, working out of DA Nang in the north, provided similar area communications support in the I and 11 Corps Tactical Zones located in the northern part of South Vietnam.

The 362d Signal Company, which was organized to operate the long-lines tropospheric scatter system, established its headquarters at Nha Trang in central Vietnam and immediately began deployment of its highly mobile tropospheric scatter terminals, of which


Photograph: Signal Opeating Mobile Manual Switchboard in 1962


six were sent to Thailand. These six terminals were put into operation in January 1963 by the 362d Signal Company to furnish long-lines support to the joint US Military Advisory Group, Thailand; they were transferred to the 207th Signal Company in Thailand during December 1963. Ten of the remaining fourteen terminals were put into operation in Vietnam supplying tails from the BACK PORCH system between DA Nang and Hue, DA Nang and Quang Ngai, Pleiku and Ban Me Thuot, Saigon and Soc Trang, and Saigon and Can Tho. The Can Tho terminal was moved to Vinh Long in mid-1963. Regarding these early efforts, a brief history of the 39th Signal Battalion states: "Hardships were shared- by all, often in insecure areas with . . . Viet Cong harassment. Speed was [the] order of the day and despite [rather poor] conditions, the men of the 39th, throughout the Republic of Vietnam, had begun the installation of the system."

The 39th Signal Battalion, meanwhile, was assuming more tasks. In May 1962 the battalion was charged with operating and maintaining the US advisers' voice radio net. Later in December 1962 it assumed operational responsibility for the countrywide


Photograph: Installing Inflatable Antenna For A Mobile Radio Tropospheric Scatter Terminal


US advisory Operations and Intelligence Radio Net down to elements located at South Vietnamese division level. The battalion received an augmentation of over 200 soldiers from the Military Assistance Advisory Group, Vietnam, to operate this network. In order to supervise the battalion's widespread operations, located at thirty-two sites throughout South Vietnam, a System Control was established. The System Control staff also planned and engineered proposed systems.

Control and Direction Over Communications

Early in 1962 the staff of the Commander in Chief, Pacific, believing that the buildup in Vietnam required centralized control and management of long-distance communications into, out of, and within the Republic of Vietnam, recommended to the joint Chiefs of Staff in Washington that the responsibility for the operation of the Army's worldwide communications "gateway" station


in Saigon at Phu Lam be transferred from the control of the Military Assistance Advisory Group, Vietnam, back to Department of the Army and in turn to United States Army, Pacific. As it later developed, this concept required that the station continue to provide message communications support to the advisers in Vietnam and that it be attached to the 39th Signal Battalion. As a result, in September 1962 the station, consisting of 134 officers and men, was assigned to US Army Support Group, Vietnam, and in addition was attached to the 39th Signal Battalion for operational control.

The station had previously become part of the worldwide Defense Communications System after the establishment of the Defense Communications Agency on 12 May 1960. In 1962 the mid­range plan of the Defense Communications Agency assigned responsibility for the Defense Communications System in Vietnam to the US Army. Yet technical control and direction of this station became increasingly subject over the years to the Defense Communications Agency.

The over-all control and direction of communications in Vietnam was vested in the US joint communications-electronics staff in Saigon. Direction was provided to the 39th Signal Battalion from that staff office through the Army component Signal Officer, Headquarters, US Army Support Group, Vietnam. The commanding officer of the 39th Signal Battalion had dual responsibilities during this period and was referred to as being "dual-hatted." He was both battalion commander and the US Army's Vietnam signal staff officer.

Improvements, Problems, and Plans to Mid-1964

During 1963 and early 1964 US Army Signalmen continued to operate and improve the communications system installed in 1962 and early 1963. An additional mobile tropospheric scatter link was installed, connecting Ban Me Thuot in the Central Highlands to the small town of Gia Nghia in west central Vietnam near the famous Duc Lap Special Forces Camp. By mid-1964 a similar link was established between Gia Nghia and Saigon. Thus twenty-four channels of communications, passing over these new links and the one previously established between Ban Me Thuot and Pleiku, were available from Saigon to Pleiku in the Central Highlands. This three-link system became known as CROSSBOW. (Map 2)

A major improvement in the capability to relay messages into and out of the Department of Defense's worldwide network was made in January 1964 upon activation of a 50-line message relay facility operated by Strategic Army Communications Station, Viet-


Map 2: Back Porch System and "Tails," Mid-1964


nam, personnel at Phu Lam. Message traffic handled by the station steadily increased during the 1962-1963 buildup. In January 1962 the station processed over 35,000 messages. The total increased to over 117,000 in October 1963 and to more than 185,000 a month


by mid-1964. Furthermore, the first circuit capable of passing low­speed data traffic was activated over the radio links of the Strategic Army Communications Station, Vietnam, connecting Saigon and the large Army logistical base in Okinawa.

The station also activated modern high-powered high-frequency transmitter equipment at Phu Lam and receiver equipment at Ba Queo, both on the outskirts of Saigon, to replace older equipment which had provided radio trunks into the worldwide Defense Communications System. These improvements were not made without difficulty. For example, when the transmitters were installed in a new building at Phu Lam, their weight caused the floor to sink into the marshy earthfill. To cope with water seepage the building had to be expanded and modified. The new facilities improved the quality of communications consisting, by early 1963, of 16 message and 3 voice channels operating on the high-frequency radio trunk to Okinawa, 16 message and 3 voice channels to the Philippines, and 12 message and 3 voice channels to Thailand.

A new Saigon overseas switchboard was installed at Phu Lam to improve long-distance telephone service. This manual switch­board had positions for four operators. However, even with this improvement, there were difficulties in placing overseas calls because of the limited reliability of high-frequency radio, particularly when operated in Southeast Asia. According to a history of the Phu Lam Signal Battalion, "The switchboard logs consistently included entries such as 'out,' 'out to fair,' 'poor to fair,' and 'out all day.' " By the end of October 1963 the switchboard was averaging thirty-three overseas calls a day, while later, at its peak in 1968-1970, over 1,500 calls were processed each day.

The Commander in Chief, Pacific, recognizing the limitations of these radio systems, had proposed as early as June 1961 a wide­band system to furnish high quality communications throughout the Western Pacific defense line. The system would interconnect Korea, Japan, Okinawa, Taiwan, the Philippines, South Vietnam, and Thailand. It would also link up with commercial undersea cables to provide circuits from Hawaii to Japan and the Philippines. The part of the system between the Philippines and Vietnam would consist of a 55-mile microwave system between Clark Air Force Base and San Miguel in the Philippines; an 800-mile submarine cable between San Miguel and Nha Trang in South Vietnam; and a tropospheric scatter radio link connecting Nha Trang with Saigon. The Air Force, which was responsible for establishing the system, awarded the contract for construction in November 1963. This system, called WET WASH, which was not completed until


January 1965, had a capacity of sixty voice channels from Southeast Asia to the Philippines. The Air Force was then charged with operating the system from the Philippines to Nha Trang; the Army was responsible for operation of the tropospheric scatter link between Nha Trang and Saigon.

Since communications with Thailand also needed improvement, a 24-channel tropospheric scatter system was proposed early in the 1960s to be installed between Saigon and Bangkok. The Army was made responsible for this 450-mile single-hop system, with Philco-Ford Corporation as the construction contractor. When activated in mid-1963, the system did not perform well be­cause the distance proved too great for operation over the path between the original site locations. It was reengineered with terminals located at a site called VC Hill, southeast of Saigon near Vung Tau, in Vietnam, and a camp at Green Hill, north of Bangkok, in Thailand. This revamped system, scheduled for completion by September 1965, the world's longest single-hop tropospheric scatter system at the time, became operational in December 1965.

For a while in the early 1960s optimism ran high at General Paul D. Harkins' joint headquarters, in anticipation of an early end to hostilities. For example, a telecommunications plan of June 1963 called for phasing out the Army's 39th Signal Battalion. This plan, which was modified by the staff of the Commander in Chief, Pacific, Admiral Harry D. Felt, and later approved by the joint Chiefs of Staff, envisaged that the communications operated by the Army would be turned over to the Republic of Vietnam. By the end of 1963 the 39th Signal Battalion was training South Vietnamese troops to operate its mobile radio relay equipment. Plans which had assumed that the Viet Cong could be eliminated by the end of 1964 provided the basis for communications efforts up to mid-1964. But they were precluded by events which drastically changed the requirements for communications in Southeast Asia.


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