The 403rd Special Operations Detachment (Abn) was the Army Security Agency’s Direct Support Unit for the 5th Special Forces Group. The unit arrived straight from Special Forces training at Ft. Bragg, North Carolina, in September 1966 with fifty-one men as part of an effort to restructure the intelligence capabilities of the 5th SFG.
Although subordinate to the 509th Radio Research Group (ASA) in Saigon, the 403rd was headquartered with the 5th Special Forces Group in Nha Trang. At full strength, their personnel were ultimately deployed to some eighty-five remote and dangerous locations in support of 3,500 Special Forces troops across the length and breadth of South Vietnam.
The ASA Green Berets were trained in Morse and voice intercept, serving as highly-trained communications intelligence operators in the field, and also performed their required duties as full-fledged members of Special Forces based on operational needs. They were a rare hybrid, bred by the necessities of a brutal war, and one of ASA’s best-kept secrets.
Those men are the forebears to today’s SOT-As.
Based on Chapter 19, “Unlikely Warriors: The Army Security Agency’s Secret War in Vietnam 1961 to 1973” by Lonnie M. Long and Gary B. Blackburn, iUniverse, 2013
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Copyright © 2013 Lonnie M. Long and Gary B. Blackburn
Photograph: The 403rd SOD courier run – Plei Ku to Kontum – 1968 (Photo: INSCOM)









































































































































