The AN/FPS-6 Radar was a long-range height finding radar used by the United States Air Force's Air Defense Command. The AN/FPS-6 radar was introduced into service in the late 1950s and served as the principal height-finder radar for the United States for several decades thereafter. It was also used by the Royal Air Force alongside their AMES Type 80s. Built by General Electric, the S-band radar operated on a frequency of 2700 to 2900 MHz. Between 1953 and 1960, about 450 units of the AN/FPS-6 and the mobile AN/MPS-14 version were produced. The AN/FPS-90 and AN/FPS-116 radars were identical to the AN/FPS-6 except for receiver modifications.