AN/TPX-27

The AN/TPX-27 was a Secondary Surveillance Radar (SSR) system, specifically an SIF/IFF (Selective Identification Feature/Identification Friend or Foe) interrogator set. Operating in the L-band (IEEE designation) or D-band (NATO designation), it was designed for the ICAO-standard Mark X SIF/IFF. This system, an advanced version of the AN/TPX-26 featuring a new encoder/decoder, was installed in the early 1980s. With a peak power of 1.5 kW, a pulsewidth of 3 × 1 µs, and an instrumented range of 190 miles (306 km), it served as an auxiliary device to a primary L-band radar, such as the HIPAR of the Nike missile system, utilizing the primary radar's antenna reflector.

radartutorial.eu: https://www.radartutorial.eu/19.kartei/14.ssr/karte032.en.html