OVERVIEW:  The FRONT DOOR-C aka "Argument” aka Argon 1164 is a  tracker/command radar for the SS-N-3/SS-N-12 missile system for use on  surface ships.  It operates in the NATO "F" band.  The companion FRONT PIECE operates in the NATO E/F band.

DETAILS:  
The FRONT DOOR/FRONT PIECE tracker/command radar is comprised of two separate systems: the FRONT DOOR is a nodding height finder/tracking radar, and the smaller S-band FRONT PIECE is an azimuth tracking and data-link guidance antenna and is mounted on the top of the larger FRONT DOOR antenna.  After launch the SS-N-3 or SS-N-12 would climb to cruise altitude following datalink steering commands, with the missile’s position tracked by the Front Door/Front Piece radars using a beacon transponder. The missiles' onboard radar would detect the targets and transmit an image back to the submarine via video datalink so the crew could select which target to attack, after which the missile relied upon its own radar for terminal guidance. 


Specifications:

	Frequency:	FRONT DOOR: 3-4 GHz (F-band (NATO)); FRONT PIECE: 2-4 GHz (E/F band (NATO))
	PRF:		?? Khz (air-to-air)
	Pulse width:	?? µ sec (air-to-air)
	Power: 		?? kW (peak) 
	Scan Limits:	??    
	Range:		?? nm (instrumented)
	
			
NOTES:  IOC 1958 (approx.).  The surface-ship version was initially designated TRAP DOOR.  These were subsequently redesignated as FRONT DOOR-C.  The major difference between the submarine and surface ship versions is that the submarine version folds for stowage when the submarine is submerged.



SOURCES: Friedman, The Naval Institute Guide to World Naval Weapons Systems 1997-98, pg. 336 ; Polmar, Norman and Moore, Kenneth,  Cold War Submarines: The Design and Construction of U.S. and Soviet Submarines, Potomac Books, Inc, 2014, Footnote 34; Jane's Radar and Electronic Warfare Systems 2002-03, "Front series missile guidance radars (02 July 2001); NATO, CURRENT SOVIET BLOC ELECTRONIC EWUIPMENT, Vol A: SHIPBORNE, dtd 12 Feb 1968, pg. I-B-41.  Available at https://archives.nato.int/uploads/r/nato-archives-online/7/e/7/7e7bdc7569e4f683c39b35e1e3da9fcebf56096cfd1d8f73bc80df03e6b2f014/MC_0262_A_67_FINAL_ENG_PDP.pdf ; Kopp, Dr C. "Soviet/Russian Cruise Missiles." Air Power Australia. Accessed June 8, 2023. https://www.ausairpower.net/APA-Rus-Cruise-Missiles.html. ; Kopp, Dr C., AFAIAA, SMIEEE, and PEng. "MARITIME STRIKE - The Soviet Perspective." Air Power Australia. Accessed June 8, 2023. https://www.ausairpower.net/TE-Sov-ASuW.html.
