Signal Corps in Vietnam
As early as 1950 the US sent Signal Corps advisors to Vietnam to monitor the distribution and use of signal equipment and to establish an Army Command and Administrative Network (ACAN) station in Saigon. After the French withdrawal from Indochina, a US advisory group remained behind to assist the S. Vietnamese. American signal advisors were assigned down to division level and to each of the country’s military regions to provide training and other support. By 1960, a private firm, Page Communications Engineers, began building a 7,800 mile Pacific scatter system for the Army from Hawaii to the PI. From there the Strategic Army Communication Network system made the final jump to Indochina.
Jan 1962: Secretary of Defense McNamara approved the installation of troposcatter equipment within South Vietnam to provide the backbone of a strategic network known as BACKPORCH. The system used large Billboard relay antennas that began to appear on mountaintops. Because the army had little experience with troposcatter equipment, Page agreed to operate and maintain the system for a year. September 1962, installation of BACKPORCH completed and turned over to the 39th Signal Battalion in September 1963.
Scatter worked by bouncing radios beams off the layers of the atmosphere, which reflected them back to earth. TROPOSPHERE SCATTER: bounced signals off the water vapor in troposphere, the lowest layer. IONOSPHERE SCATTER: bounced signal off clouds of ionized particles in the ionosphere, which starts about 30 miles above the earth. Used special antennas that were less susceptible to jamming and did not require LOS as did the microwave relays. TROPO stations could be as far as 400 miles apart compare to about 40 miles for microwave.
To provide the support for operations in this new conflict, the 1st Signal Brigade of the US Army Strategic Communications Command had more than 23,000 soldiers assigned, the largest signal organization ever deployed to a combat area.
Find out more in "Getting the Message Through" at http://www.history.army.mil/books/30-17/Front.htm#toc