Early SIGINT Efforts in Vietnam (Part 4 of 7)

In January 1962, the AFSS elements finally arrived in Vietnam. They split up between the two air bases. Two H-1 intercept vans were airlifted from the Philippines to Danang while another four vans, including the HFDF station and the AFSSO operations complex were flown into Tan Son Nhut. A few months later, the intercept mission at Tan Son Nhut was moved to Danang because of the better HF reception there.

At first, the Air Force’s VHF intercept mission at Danang was a bust. The problem was caused by the terrain surrounding the air base: on three sides it was closed in by mountains three to twelve miles away with peaks as high as five thousand feet. Onl ‘ the mouth of the harbor was open [ — ]. The ASA element, which had been training the local ARVN J-7 COMINT personnel manning their own site at the harbor, had found no VHF; even HF was difficult to hear. Any intercept of VHF communications emitted from aircraft flying at medium-to-low altitudes beyond the mountains was almost impossible. The only way to hear anything on the VHF range was to relocate to a better site.