OVERVIEW: The AN/FPS-118 ground-based, Over-the-Horizon Backscatter Radar System (OTH-B) is a very long-range air surveillance radar, operating in the "A" Band. 

DETAILS: Original design configuration included plans for three OTH-B radar systems in the continental United States (East Coast, West Coast, and Central facing south) and one in Alaska. They were to be coupled with a strengthened North Warning System (NWS), which runs along the north slope of Alaska and across the northern edges of Canada.

With the end of the Cold War, just months after their deployment, the OTH-B radars on the West Coast were placed in caretaker status, the Central and Alaska Systems were cancelled, and the East Coast system was redirected to counter-narcotics surveillance. Due to the high cost of operations, along with outdated technology, the East Coast system formally ceased radar operations in October 1997 and joined the West Coast system in caretaker status. Today, the remaining two sites are maintained in caretaker status until they can be sold, transferred, or otherwise disposed of. 

Specifications:

Frequency: 		5-28 MHz (A Band)
Power output: 		 (average);   1 MW (peak) 
PRF:			unknown Hz	
Range Resolution:	unknown (range),  unknown azimuth 					
On/Off time:		unknown
Deploy/Stow Time	N/A






Notes: Over the Horizon Backscatter radar. Most were mothballed after the end of the Cold War.

NOTES: OTH-B radar systems use the ionosphere to refract outgoing radar waves and return signals, enabling the system to detect and track targets that would otherwise be hidden by the curvature of the earth. 

SOURCES: Air Combat Command - Home. "Factsheets : Over the Horizon Backscatter Radar: East and West." Accessed November 24, 2013. http://www.acc.af.mil/library/factsheets/factsheet.asp?id=3863 ; Federation of American Scientists. "AN/FPS-118 Over-The-Horizon-Backscatter (OTH-B) Radar - United States Nuclear Forces." Accessed November 24, 2013. http://www.fas.org/nuke/guide/usa/airdef/an-fps-118.htm.
Wikipedia, the free encyclopedia. "Over-the-horizon radar." Accessed November 24, 2013. http://en.wikipedia.org/wiki/Over-the-horizon_radar ; AN/FPS Series." Alternate Wars. Accessed March 22, 2015. http://www.alternatewars.com/BBOW/Radar/FPS_Series.htm.
