Project touchdown: how we paid the price for lack of communications security in Vietnam - A costly lesson

Army Communicator, Spring, 2003 by David Fiedler

In late 1969, I and every other member of 1st Signal Brigade and 160th Signal Group's 44th Signal Battalion were searching for Viet Cong or North Vietnamese Army spies within our local-hire Signal workforce. (The Vietnamese locals were mostly base-camp telephone-switchboard operators, installers and repair personnel that 1st Signal Brigade employed in its base-camp facilities.) At that time, the G-2, U.S. Army Vietnam--our command headquarters--was convinced that, because so much of our operational information was apparently in the enemy's hands and we were taking such high casualties, espionage on a large scale was the only possible explanation.

G-2 also felt that the most likely location for espionage was at major Signal locations where operational information was concentrated and there was also a large local civilian workforce. In fact, in 44th Signal Battalion, we caught one of our cleaning women with a stolen manual for the AN/FRC-93 high-frequency radio (also known commercially as the Collins KWM-2A) at a gate search. She was turned over to the Vietnamese National Police, which was probably tantamount to a death sentence for the woman, and that bothers me even today because she was probably innocent. She probably wanted the manual for toilet paper, since such a use for publications was common among the Vietnamese.

Almost everyone was quite happy with this "spy capture" except myself and a few others. We failed to see how obtaining a manual that could be bought in any amateur radio store in America would be of much value as technical intelligence to the enemy. In addition, we thought our losses were clearly the result of operational, not technical, communications intelligence.

No spy ring, just arrogance

Thanks to our battalion S-2, 44th Signal Battalion soldiers were aware as early as 1965 that the enemy was probably monitoring USARV tactical-radio nets. The Army Security Agency tried to make everyone else a believer in this, too. However, as I mentioned in my article in the last Army Communicator [Books, Winter 2002 edition], despite ASA's many warnings, it was USARV's official opinion that the NVA/VC had no equipment capable of monitoring U.S. tactical-radio nets, nor could they understand English well enough to use the information if they had the equipment and, most importantly, our tactical forces moved so fast and our actions on the battlefield were so quick that even if the enemy managed to acquire some information from our tactical-radio nets, it would do them no good and us no harm. That arrogance was to cost us dearly.

At this point, it's important to know that by 1965 frequency--modulation voice radio had been deployed to every level of command from squad to corps (and higher). It's also important to know that this radio equipment, AN/PRT-4 and AN/PRR-9 (handheld radios for squads or platoons), AN/PRC-25 (manpack and vehicular for platoon, company or battalion) and AN/ VRC-46 (vehicular, platoon through corps and higher) did not have any communications-security provisions at the Vietnam War's outset.

Since there was no COMSEC device, either internal or external, provided to this equipment until late in the conflict, the only solution was to constantly stress the vulnerability of FM voice radio to intercept and analysis and to carefully use Signal operating instructions, off-line (paper) operations codes and authentication tables (challenge and reply) to provide net security. As I said, however, before late 1969, the USARV and Military Assistance Command Vietnam commanders steadfastly refused to believe there was a real COMINT threat. This attitude was reflected across the entire force at every level.

Accordingly, since existing operations codes and authentication tables were cumbersome for the typical poorly trained FM voice radio operators (most of who were officers and senior noncommissioned officers) to use, they were rarely employed. Field commanders clearly believed that time was more important than security. This view was reinforced in the combat-arms training base, where very little time was devoted to communications subjects, even though the Signal Corps had declared combat-net-radio equipment to be "user-owned and -operated."

Unit Signal officers (S-6/G-6) magnified the hemorrhage of vital tactical information over the radio because many of these officers were cowed by higher headquarters and tactical commanders into also believing there was no COMINT threat. By direction, Signal officers rarely, if ever, took even the minimal action of just simply changing net call signs and frequencies.

Taken together, our COMSEC laxness--created by our arrogant assessment of the enemy's capabilities and intelligence--led to a massive opportunity to intercept and exploit our tactical FM communications nets our astute enemy used to extreme advantage.

While we in the Signal Corps tout good communications as a combat multiplier, we rarely mention that Vietnam proved enemy exploitation of our communications is deadly. No one to my knowledge has ever been able to calculate the number of names on the Vietnam Wall due to poor COMSEC, but all indications are that the number is considerable. The number of Americans killed and wounded in action due to lack of radio security certainly must, in my opinion, far exceed the much-publicized losses due to friendly fire or non-combat related deaths due to accidents, for example.