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Type 271

Description of the radar set, tactical-technical characteristics

Figure 1: “Double cheese” antenna of Type 271 radar

Figure 1: “Double cheese” antenna of Type 271 radar

Specifications
frequency: S-Band
pulse repetition time (PRT):
pulse repetition frequency (PRF): 500 Hz
pulsewidth (τ): 0.7 or 1.5 µs
receive time:
dead time:
peak power: 7 kW
average power:
instrumented range: 11 NM (≙ 20 km)
range resolution:
accuracy: 250 m, 2°
beamwidth:
hits per scan:
antenna rotation: 2 min-1
MTBCF:
MTTR:

Type 271

Type 271 is an early operating in S-Band British naval sea search radar, available when war broke out in Europe. It has been delivered since April 1941 and was equipped initially with an A-scope display. Later versions had a PPI display. It was fitted primarily to escort vessels (corvettes and frigates). It used a “double cheese” antenna enclosed in a Perspex (plexiglass) “lantern” (a very early kind of radome). One antenna was for receive and the other for transmit. The antennas were steered using an automobile steering wheel from an operator's station directly below the “lantern”. This arrangement minimized the length of the coaxial cables used in this very early microwave set.

An improved version, Type 271Q, was introduced in 1943 and had a much more powerful magnetron (100 kW) and correspondingly greater range.