OVERVIEW:  The SNR-75 aka SA-75M Dvina aka FAN SONG B radar is a trailer-mounted target acquisition and missile guidance radar for the SA-2D and SA-2F GUIDELINE SAM.  It operates in the NATO E/F- band (IEEE S-Band).

DETAILS:  The FAN SONG illumination radar systems is associated with the SA-2-series SAM.  The SNR-75 family of radars employ a complex antenna arrangement which is employed to provide range and angle tracking of the intended target, as well as the transponder beacon in the SA-2 missile, which is flown to a collision with the target using a command uplink embedded in the SNR-75 radar.

The antenna system consists of a pair of antennas: Two of electromechanically scanning (aka "Lewis-scanner") antennas provided vertical and horizontal target search, usually conducted in conjunction with the battery's P-12 SPOON REST and a height finding radar, such as the PRV-10 ROCK CAKE. This arrangement was made necessary because to the narrow, 10° × 2° surveillance beams of the FAN SONG radar could only be steered through a 10° arc.   These perpendicularly mounted antennas created a cross-shaped beam that was centered on the target to determine its height and azimuth. These beams perform a 'flapping' motion as they scan their sectors. The FAN SONG radar had a dead zone at low altitude, which, unless covered by AAA, allowed attacking aircraft a potential avenue of attack. 

A UHF (0.3-1.0 GHz) parabolic antenna mounted on the right side of the array transmitted command signals to the missile, guiding it to the target, while the missile transponder beacon is tracked by the Lewis antennas. 

The FAN SONG can track up to four targets simultaneously and engage a single target with up to three missiles.    The missile must pass through the guidance beam within seconds of launch to be acquired and steered to its target.
  

Specifications:

	Frequency:	2.965-2.990; 3.025-3.050 GHz (High E, Low F-band (NATO))
	PRF:		1100-1250; 2200-2500 pps (est)
	Power: 		 600 kW (peak)
	Range:		32,64 nm (instrumented); 
	Accuracy:		60, 180 m (est)
	Deploy/Stow time	60 minutes (approximate)
		
NOTES:  IOC 1960.  Associated with the SA-2B mod 1


SOURCES:    Jane's Radar and Electronic Warfare Systems, "Fan Song missile control radars," 02 July 2001;  https://www.radartutorial.eu/19.kartei/11.ancient/karte030.en.html ; Kopp, D. C. (n.d.). Engagement and fire control radars (S-band, X-band). Air Power Australia. http://www.ausairpower.net/APA-Engagement-Fire-Control.html and http://www.ausairpower.net/APA-SNR-75-Fan-Song.html; Steven J. Zaloga, "Red SAM: The SA-2 Guideline Anti Aircraft Missile" New Vanguard, pg. 41. ; Pike, John. "FAN SONG." GlobalSecurity.org. Last modified 7, 2019. https://www.globalsecurity.org/military/world/russia/fan-song.htm; NATO, "Current Soviet Electronic Equipment, Vol. C: Landbased, pg. I-C-13 (12 February 1969); SA-2 surface-to-Air missile. (n.d.). National Museum of the United States Air Force™. https://www.nationalmuseum.af.mil/Visit/Museum-Exhibits/Fact-Sheets/Display/Article/196037/sa-2-surface-to-air-missile/; RSN-75 : USSR / Successional countries USSR (SOV). (n.d.). Armedconflicts.com. https://www.armedconflicts.com/RSN-75-t74858 ; IBP. (2007). Pakistan army weapon systems handbook volume 1 strategic information and weapon systems. Lulu.com, pg. 244.


