1S91 “Straight Flush”

The 1S91 "Straight Flush" is a C-band missile guidance radar, operating with a peak power of 600 kW and an instrumented range of 75 km, designed for the Kub (SA-6 "Gainful") surface-to-air missile system. It features a 1° beamwidth and an antenna rotation speed of 15 or 20 revolutions per minute. The system includes a high-resolution TV camera for visual target tracking, and its target tracking and illumination radars operate in X-band, utilizing a secondary radar method with "active response" for missile tracking. The 1S91 was adopted by the Soviet Union in 1967 and widely used by Warsaw Pact nations; notably, it was involved in the mistaken downing of Malaysia Airlines MH17. The radar's antenna unit, comprising a rectangular parabolic cutout for surveillance and a solid circular parabolic reflector with a planar sub-reflector for fine search and target tracking, is mounted on a tracked vehicle and can rotate 360 degrees independently of the search radar.

radartutorial.eu: https://www.radartutorial.eu/19.kartei/06.missile/karte011.en.html