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Description of the radar set, tactical-technical characteristics

Figure 1: AN/FPS-27

Figure 1: Antenna of AN/FPS-27A as a static display

frequency: 2 322 … 2 670 MHz
(S band)
pulse repetition time (PRT):
pulse repetition frequency (PRF): 226 … 288 Hz
pulsewidth (τ): 6.5 µs
receiving time:
dead time:
peak power: 15 MW
average power: 30 kW
instrumented range: 220 NM (≙ 410 km)
range resolution:
hits per scan:
antenna rotation: 5 rpm


AN/FPS-27 was a frequency diversity long-range search radar designed to operate in the S band at 2322 to 2670 MHz. The radar was designed to have a maximum range of 220 nautical miles and search to an altitude of 150,000 feet (46 km). It used a vertically stacked beam to estimate the targets height. System problems required several modifications at the test platform located at Crystal Springs, Mississippi. Once these problems were solved, the first of twenty units in the continental United States became operational a Charleston, Maine, in 1963. The last unit was installed at Bellefontaine, Ohio, a year later. In the early 1970s, AN/FPS-27 radar stations that had not been shutdown received a modification (solid-state circuitry replacing vacuum tubes) that improved reliability and saved on maintenance costs.