SDR recording catch, according to the N&O newsletter, "RGT77 is the General Staff Broadcast out of the Kremlin and has been using the same callsign since before World War II."
RGT77 RGT77 251X CUWNG WMGTA AMYEKU UVNA NTFNS FTTMKJ WARB JBBPI NTRE BQWRO RTDIMH EPV TS K