from NAS Keflavik. Final EC-121 ops ended in September 1978. Detachment 1 dissolved and 79th AEWCS was redesignated a fighter squadron on 1 October 1978. In 1967, five EC-121s became operational with the 193rd Tactical Electronic Warfare Squadron of the Pennsylvania Air National Guard, responsible for psyops missions under project Coronet Solo. From July 1970 to January 1971, they rotated on 30- to 90-day temporary-duty deployments to Korat Royal Thai Air Force Base, Thailand, under the name Commando Buzz. Vietnam War EC-121s were used extensively in Southeast Asia between 16 April 1965, and 1 June 1974, particularly in support of Operation Rolling Thunder and Operation Linebacker/Linebacker II, providing radar early warning and limited airborne control of USAF fighter forces engaging MiG interceptors. Flying orbits over the Gulf of Tonkin and later over Laos, they were the forerunners of AWACS aircraft. The USN used a variant, the NC-121, in their Blue Eagle unit from 1965–1972. Blue Eagles were television- and radio-broadcasting airplanes. The Blue Eagles were based at NAS Patuxent River and were part of oceanographic squadron VXN-8. Big Eye At the onset of Rolling Thunder, the North Vietnamese had an advantage in that their radar coverage could detect most US strike aircraft flying at or above 5,000 feet virtually anywhere in the country, using a system that was difficult to jam. US forces countered with radar ships (Crown) in the Gulf of Tonkin and a ground site at Nakhon Phanom RTAFB, Thailand, but both systems were line-of-sight and suffered coverage gaps. To increase coverage, the Seventh Air Force (7 AF) requested airborne radar support and the Air Defense Command (redesignated Aerospace Defense Command in 1968) was directed to set up the Big Eye Task Force. Five EC-121Ds and 100 support personnel of the 552nd AEWCW at McClellan AFB were deployed to Tainan Air Station, Taiwan, with four of the EC-121s sent on to a forward operating location at Tan Son Nhut Air Base, near Saigon, Republic of Vietnam. The EC-121s were designed for detection of aircraft flying over water, so ground clutter (spurious signal returns off of terrain features such as mountains) caused interference with their radar pictures. The crews, however, were experienced in tracking Soviet aircraft over Cuba and had developed a technique whereby an EC-121 flying at 50 to 300 feet above water could bounce a signal from its bottom-mounted APS-95 Search radar off the surface of the