The Type 965 radar was VHF long-range aircraft warning radar used by warships of the Royal Navy from the 1960s onwards. The Type 965M, Type 965P, Type 965Q and Type 965R were improved versions; the Type 960, 965M and 965Q used the single bedstead AKE aerial, whilst the Type 965P and 965R used the double bedstead AKE aerial. The 965 is ultimately designed to a May 1950 requirement for a further updated version of the 1945 Type 960. The 960 provided long-range early warning on small ships, but had a very wide beam at 35° horizontal. In 1954 the idea of a general-purpose frigate with the ability to provide some fighter direction arose, which required a radar with a much narrower beam. Marconi responded with the 965, reducing the beam to 12°. Based on WWII technology, the 965 was subject to considerable radar clutter from waves. The Type 965Q and 965R were improvements on the 965M and 965P respectively, adding a COHO-based moving target indication mode to suppress clutter. Designed before the introduction of Doppler filtering, it was not able to detect low-level targets against a background, either landforms or high waves. The lack of a true MTI proved to be a serious problem during the 1982 Falklands War, which ultimately led to the loss of where Argentine aircraft could not be seen against the background of the islands. Similarly, the Type 965 could not detect aircraft flying low; the two Argentine NavySuper Étendards that caused the loss of were not detected by Type 965R radar when they were flying at, but were shown as contacts by 's Type 965R radar when they popped up to above sea-level at, though it was the UAA1 radar warning receiver that drew attention to the contacts. The Type 965 radars used radio frequencies that were used by television stations, and therefore caused interference with television if used near land in Europe. Type 965 was superseded by the Type 1022 radar, which did not have this disadvantage.
Why the Type 965 was procured
During 1954-55, reports on most fleet exercises showed that there was an urgent need for radar picket ships. These would require a suitable radar. The need for such a radar had been raised as a staff requirement in May 1950. In 1955, four radars were considered:
The American SPS-6C radar, which was credited with a range of at, and at.
The Dutch LW-02 radar, which was credited with a range of at.
Extending the range of the Type 992 radar, by slowing its scanning rate.
A potential route for the Royal Navy to get the SPS-6C was the Mutual Defense Assistance Pact, but by 1954-5 the MDAP programme was running down. In addition, it was thought that getting spares for the SPS-6C radar could be a problem, because the United States Navy considered it obsolescent. The Marconi design was chosen and was named Type 965. The Type 965M was introduced in about 1960, and used the original AKE aerial with an improved receiver and feeder.
Ships with Type 965 radars
Type 965M with AKE aerial
*The aircraft carrier HMS Ark Royal was given a Type 965M system on her foremast when modernised in 1958-59.
*Type 41 Leopard-class frigates when modernised.
*Tribal-class frigates.
*Type 12M Leander-class frigates.
*Weapon-class destroyers modernised to air direction destroyers.
*County-class destroyers Batch 1.
*The aircraft carrier HMS Centaur when refitted in 1963. The radar was taken from the air direction destroyer Battleaxe.
*Tiger-class cruisers when modernised in the late 1960s.
*The carrier HMS Hermes when converted from the aircraft carrier role to the commando carrier role in 1971-73.
Type 965P with AKE aerial
*Battle-class destroyers - the four that were modernised to air direction destroyers.
*Type 61 Salisbury-class frigates when modernised in 1961-68. HMS Chichester had her Type 965 removed in 1973 when she was refitted as Hong Kong guardship.
*County-class destroyers Batch 2.
*The aircraft carrier HMS Eagle was given a Type 965Q on her lattice foremast when modernised in 1959-64.
*Type 82 Bristol-class destroyer, before it was replaced by Type 1022 radar when she was modernised in 1984-6.
Type 965Q with AKE aerial
Type 965R with AKE aerial
*The aircraft carrier HMS Ark Royal was given two Type 965R systems on separate masts when modernised in 1967-70.
*Type 42 Sheffield-class destroyer Batch 1; Batch 2 had the Type 1022.
Technical Specifications
A common aerial was used for transmitting and receiving. This was the single bedstead AKE in the Type 965M, and the double bedstead AKE in the Type 965P. The 965M and 965P were integrated with IFFMk 10. The radar displayed both to an "office display unit", and up to six remote plan position indicator displays. The Type 965M and 965P had the following specifications:
Differences between Type 960 and 965M
Type 965 receiver noise factor: 8 dB.
Type 965M receiver noise factor: 4.5 dB.
Type 965M feeder was 1 dB better than the Type 960 feeder.
The receiver of the Type 965Q and 965R used "a coherent oscillator to provide the coherence in phase between transmission and reception. The COHO is phase locked to the transmitter pulse." With the Type 965Q and 965R, the pulse repetition frequency had a number of different settings.
In non-MTI mode, the PRF was set by the Pulse Synchronising Outfit RSE.
In MTI mode, to avoid interference from other radars, there were five available pulse intervals, each with a corresponding stagger time. Pulse intervals were ±3 μs; stagger times were ±2 μs.
