www.radartutorial.eu www.radartutorial.eu Card Index of Radar Sets - Ancient Radars


Description of the radar set, tactical-technical characteristics

Figure 1: AN/FPS-23, at a main site with two directions

Figure 1: AN/FPS-23, at a main site with two directions

frequency: 475 … 525 MHz
( UHF-Band)
pulse repetition time (PRT):
pulse repetition frequency (PRF):
pulsewidth (τ):
receive time:
dead time:
peak power:
average power: 1 kW
instrumented range:
range resolution:
hits per scan:
antenna rotation:


AN/FPS-23 “Fluttar” (flutter radar) was an operaing in UHF-Band gap filler bistatic radar located at Main and Auxiliary DEW-Line Sites to fill the low-altitude gaps between AN/FPS-19 radars. It was a CW-Barriere Radar with separate transmitter (AN/FPT-4) and receiver (AN/FPR-2) sites, typically about fifty miles apart. The AN/FPS-23 uses the Doppler-effect to detect aircraft trying to pass between transmitter and receiver sites. Because of the many false alarms, it had only a less effect.

The first use of the AN/FPS-23 was the old Canadian Line (Mid Canada Line), the predecessor of the DEW line in 1955. These radars were decommissioned by the end of 1963.

Picture gallery of AN/FPS-23

Figure 2: Fluttar UHF transmit antenna

Figure 3: Fluttar transmitter

Figure 4: Receiver for Fluttar 1955