I served with MASS-3 in Vietnam in 1970. The Marine Air Support Squadron was located on Hill 327 on the Danang perimeter, with five ASRT (Air Support Radar Teams) in Danang, Quang Tri, Birmingham Fire Support Base, Chu Lai, and An Hoa.

The ASRT teams were about 3 officers and 7 enlisted. They operated the TPQ-10 Radar. This small van had a (for then) sophisticated analog computer. The operators put the target info into the computer, the type of aircraft, bombs, weather, etc. They would then fly the aircraft to a point in space where they would drop their bombs, supposed to be within 50 meters of the target.

Very effective weapon. It was used as a bomb disposal - close air support aircraft would fly in support of the infantry, and drop their bombs if needed directed by a FAC. If the were not needed, they would report to the ASRT, who would bomb a target.

This type of fire control made it very difficult for the NVA to mass for an attack. The ASRT missions were all weather, with fighter bombers flying high and straight above the target. If intel knew of a location of NVA, they would be attacked.