Radar sets of the County Class.

 

TYPE 965 AIR SEARCH SET

This radar has the readily indentifiable 'mattress' antenna with either a single unit (AKE-1) or a double unit (AKE-2).  Only the former were fitted to the first four ships.  It operates in P-band at 216-224MHz, with a peak power of 450kw.  The pulse repetition frequency (PRF) can be set to either 400 or 200 with pulse durations of 3∙8 or 10µs respectively.  The beam was 12° wide with a vertical spread of 40°, and it rotated at 8-10 rpm.  It had an effective range of over 175km.  There were always two different antennae for the type 965, a high-band and a low-band unit, they were driven by the same transmitter.  Both antennae were fitted to the later group of Counties to provide better frequency agility, this double set was known as the AKE-2 fit.

 

TYPE 992Q TARGET INDICATING RADAR

This radar operates at 3GHz with an output power of 1.75Mw and a pulse duration of 2µs and has an effective range of 90km against small air targets.  It can be synchronised with the Type 965 in PRF and rotation but can scan at up to 30 rpm.  The beam is 1° wide and has a vertical spread of 30°.

 

TYPE 278 HEIGHT FINDER

This radar produces a beam width of less than 5° and a vertical spread of 2∙5°.  Its effective range was 80-90km.

 

TYPE 901 MISSILE GUIDANCE

This radar provided the conical scanning beam which both tracked the target and guided the Seaslug missile.  It operated in X-band (9.00 - 9.80GHz), and had an effective range of up to 70km.  In the GWS2 system (Seaslug Mk2) the 901M radar provided a continuous wave (CW) signal to improve its performance against ECM.  The PRF was 1·3KHz with a conical scan frequency of 66·6Hz, the gathering beam width was 13·5° and the guidance beam width was 5·8°; it scanned in a clockwise direction.

 

TYPE 903 FIRE CONTROL

This radar is based on the US Mk35 set and is used in the Medium Range System 3 (MRS-3) fire-control system.  It operates in the X-band at around 900-1000Mhz with an output of 50kw.  The PRF is 3000 with a pulse duration of 0∙1 µs.  The beamwidth is 2° and the effective range is 30km.

 

Comments are welcomed at seaslug@littlewars.org.uk

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Last updated 14th January 2014.

Copyright SR Jenkins, July 2000.