The system was based on a frequency modulation/continuous wave (FM/CW) radar capable of detecting and tracking objects at over-the-horizon ranges.

A small scale test receiver/transmitter was established in central western Maine at what would become Moscow AFS by the early 1980s.

Successful testing resulted in the decision to develop operational OTH-B systems for the east and west coasts and in Alaska.

The fall of the Soviet Union and end of the Cold War saw the OTH-B systems rendered obsolete for detecting intruding military aircraft, however, the OTH-B continued operations until 1997 and its data saw use by the United States Border Patrol for tracking aircraft used by drug smugglers, as well as the National Oceanic and Atmospheric Administration which made use of the measurements of ocean currents and weather patterns.

This article incorporates public domain material from the Air Force Historical Research Agency