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Type 242

Description of the radar set, tactical-technical characteristics

Figure 1: Antenna type ASS of Type 242 interrogator

Figure 1: Antenna type ASS (“candelabra”) of Type 242 interrogator

242242 M/P/Q
Aerial outfitASWASS
frequency: 165 … 185 MHz159 … 189 MHz
pulse repetition time (PRT):
pulse repetition frequency (PRF): 125 or 50 Hzup to 500 Hz
pulsewidth (τ): 6 µs4 µs
receiving time:
dead time:
peak power: 1 kW2 or 10 kW
average power:
instrumented range:
range resolution:
beamwidth: 60°88°
hits per scan:
antenna rotation:

Type 242

Type 242 is an operating on a fixed frequency in VHF-band interrogator in the standard Mark Ⅲ IFF system.

The Type 242 is used in conjunction with the radar Type 275 and Type 291. Type 242M is used in conjunction with the radar Type 277 series and Type 293. Type 242P/Q is normally used with Types 960/982 and the height-finder Type 983.

The PRF of the main radar equipment is counted down (4:1 or 10:1) in the modulator which fires the interrogator transmitter and also a trace displaced from the radar trace on the A-scope. The interrogator signals are received by the responser unit and displayed on this trace as inverted signals along with the normal echoes. Coincidence of the interrogator pulse and the radar echo identifies the target.

The associated shipborne transponder is Type 253 series or Mark Ⅲ IFF when fitted in aircraft.

Picture gallery of Type 242

Figure 2: The older one antenna ASW “pitchfork” with a wind balancing vane.