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Type 281

Description of the radar set, tactical-technical characteristics

Figure 1: Type 281B Aerial on board HMS SWIFTSURE at Scapa Flow
(the vertical polarised pair of antennas on top ist the Type 243 IFF interrogator)

Figure 1: Type 281B Aerial on board HMS SWIFTSURE at Scapa Flow
(the vertical polarised pair of antennas on top ist the Type 243 IFF interrogator)

First manufacturer: Signal School Workshops (UK)
Specifications
Type 281Type 281B
frequency: 39 … 72 MHz
(HF-Band)
86 … 94 MHz
(VHF-Band)
pulse repetition time (PRT):
pulse repetition frequency (PRF): 50 Hz
pulsewidth (τ): 15 or 3 µs
receive time:
dead time:
peak power: 60 … 70 kW350 or 1 000 kW
average power: 2 kW
instrumented range: 100 NM
(≙ 185 km)
120 NM
(≙ 222 km)
range resolution:
accuracy:
beamwidth: 35°
hits per scan:
antenna rotation:
MTBCF:
MTTR:

Type 281

Type 281 is operating in HF-Band British naval early warning radar introduced in 1940. The first version used different antennas for transmitting and receiving. In 1943, a single mast version of type 281 became available, called type 281B. Its transmitter used a pair of type NT 86 high power valves.