AN/APX-7

The AN/APX-7 is an airborne Secondary Surveillance Radar (SSR) operating in the L-band at frequencies of 1030 MHz and 1090 MHz with a peak power of 2 kW. This interrogator-responder, also known by its British designator Airborne Interception Radar Mk IX, was designed to identify aircraft as friendly or hostile. It could display interrogation results as an additional pulse on the A-scope of the AN/APS-20 radar. The system's antenna is a diamond-shaped metal plate encased in a streamlined plastic housing, weighing one pound and measuring 9-13/32 inches long, 3-11/64 inches wide, and 7-3/16 inches high. It is mounted vertically on the aircraft's centerline at its lowest point, with its radio-frequency line section projecting into the aircraft through a cutout.

radartutorial.eu: https://www.radartutorial.eu/19.kartei/14.ssr/karte027.en.html