OVERVIEW:  The RPB-2K aka Initsiativa aka MUSHROOM radar is a airborne surface search radar operating in the NATO I- Band (IEEE X-Band).

DETAILS:   The MUSHROOM  radar is a naval surface search radar.  It  was also used as a navigation and bombing radar in early Soviet bombers.


Specifications:

	Frequency:	9.3-9.5 GHz (approx) (I-band (NATO))
	PRF:		460-585; 1075-1300 pps
	Pulse width:	0.25-1.5 ms
	Power: 		 40-100 kW (peak)(est)
	Range:		100 nm (est) 
	Accuracy:		±2% (range); ±2° (azimuth)
			
NOTES:  IOC 1960's.  Possibly based on APS-15 and APQ-13 ground scanning radars.  

SOURCES:  Friedman, The Naval Institute Guide to World Naval Weapons Systems 1997-98, pg. 199.; NATO "Current Soviet Bloc Electronic Equipment, Vol B: Airborne, 12 Feb 1968,  pg. I-B-1. https://archives.nato.int/uploads/r/nato-archives-online/a/7/7/a77acfea6fe1accb0f9f55c6d8ab8f399a40d17ca9efc0fdcc9b0211e989463a/MC_0262_B_68_FINAL_ENG_PDP.pdf


