Started staged move to Edinburgh SA in 1976 to transition to P3B/P3C Orion. Max. radar range was determined primarily by pulse repetition frequency (PRF), which gave a theoretical range of about 250nms. Actual max range was limited by the display range of the ASA16 indicator which was 200nms. The APS20 was used primarily on the Neptune as an ASW snort detection radar with the aircraft flying at about 1000feet to allow an effective radar/visual search. This gave a radar horizon of about 30nms. High level fishery and naval surface surveillance was conducted up to 10000 which gave a detection range of about 140nms (1.4x root Ht).
