 In August 1966, the USAF installed a TACAN System, an autonomous radio transmitter that provided pilots and navigators with distance and bearing relative to the station on Phou Pha Thi.In 1967, under the code name "Heavy Green", the facility was upgraded with the TSQ-81, which could direct and control attacking jet fighters and bombers to their targets and provide them with precise bomb release points.It began operating in late November 1967 as Operation Commando Club.