sentences:  In 1964 the AN/FPS-66 was replaced by a Westinghouse AN/FPS-27 Radar.The other AN/FPS-6 height-finder radar was retired in 1964.In addition to the main facility, the Watertown squadron operated two unmanned AN/FPS-14 (P-49A) and AN/FPS-18 (P-49B) Gap Filler sites