AN/FPS-118 OTH-B radar

The AN/FPS-118 Over-The-Horizon Backscatter (OTH-B) radar system consisted of a transmitter and a receiver located approximately 100 miles (161 km) apart. The OTH-B used emissions bounced off the ionosphere to acquire targets up to 2,000 nm (2,303 mi, 3,706 km) away; its dependence on atmospheric conditions was a source of concern, but the OTH-B was the only ground-based system with such a range. Minimum range was approximately 500 nm (576 mi, 927 km); the radar was blind to...