NRS-12 “Score Board”

The Russian-made NRS-12 “Score Board” is an early Secondary Surveillance Radar (SSR) designed by ОАО «ВНИИРТ». Its antenna array consists of two horizontal rows, each with two radiator elements, stacked to form a four-element array, totaling 32 dipole radiators mounted on a rectangular, rotatable framework. Operating in the UHF band, the system uses a “Kremnij-2” interrogator that transmits pulse groups, which are then modulated by a transponder with an audio frequency, processed through 12 distinct frequency filters. The “12” in its designation indicates its intended use with the P-12 radar and subsequent models of the “Spoon Rest” VHF-radar family, with a variant, the NRS-20, designed for the P-37 “Bar Lock” radar, and another version integrated into the SA-2 “Guideline” (S-75 “Wolchow”) missile system.

radartutorial.eu: https://www.radartutorial.eu/19.kartei/14.ssr/karte002.en.html