AN/APR-9

The AIL\Collins AN/APR-9 was a radiofrequency receiver produced in the United States. It saw versatile use in various roles, including electronic intelligence (ELINT), electronic warfare support measures (ESM) and radar warning receiver (RWR) equipment.
Its frequency range is 1,000–10,750 MHz.
It saw airborne use mounted on A-1, B-52, B-57, EB-66, EC-121, P-2, P-5, S-2 and AF-2W and RB-36 aircraft and ZPK airships.
It also has been used ground-based, when referred to as AN/MLQ-24.
Some sources argue that an AN/APR-9 (loaned to Sweden by NSA in exchange for reports) was in use on board a Swedish DC-3 that was shot down over the Baltic Sea in 1952 on an ELINT mission towards USSR military forces.
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