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Type 965 radar

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The Type 965 radar was VHF (P band) 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(1) aerial, whilst the Type 965P and 965R used the double bedstead AKE(2) aerial.[1][2][3]

Type 965M and Type 965P
HMS Coventry in 1981; the AKE(2) aerial of her Type 965R radar is at the top of her foremast
Country of originUnited Kingdom
Typenaval long range aircraft warning radar
FrequencyVHF 216-224 MHz
PRF200 or 400 p/s nominal
Beamwidth12° (horizontal), 40° (vertical)
Pulsewidth3.8 μs and 10 μs
RPM10 rpm
Power450 kW

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°.[2][4][5] 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 (MTI) mode to suppress clutter.[3] Designed before the introduction of Doppler filtering, it was not able to detect low-level targets against a background, either landforms or high waves.[1]

The lack of a true MTI proved to be a serious problem during the 1982 Falklands War, which ultimately led to the loss of HMS Coventry where Argentine aircraft could not be seen against the background of the islands.[1] Similarly, the Type 965 could not detect aircraft flying low;[1] the two Argentine Navy Super Étendards that caused the loss of HMS Sheffield were not detected by Type 965R radar when they were flying at 98 feet (30 m),[6] but were shown as contacts by HMS Glasgow's Type 965R radar when they popped up to 120 feet (37 m) above sea-level at 45 nautical miles (83 km),[7][8] though it was the UAA1 radar warning receiver that drew attention to the contacts.[7][a]

The Type 965 radars used radio frequencies that were used by television stations, and therefore caused interference with television (and vice versa) if used near land in Europe.[10] Type 965 was superseded by the Type 1022 radar, which did not have this disadvantage.[1]

Adoption

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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:[1][10]

  • The American AN/SPS-6C radar, which was credited with a range of 50 nautical miles (93 km) at 15,000 feet (4,600 m), and 90 nautical miles (170 km) at 60,000 feet (18,000 m).[1]
  • The Dutch LW-02 radar, which was credited with a range of 75 nautical miles (139 km) at 35,000 feet (11,000 m).[1]
  • A Marconi's Wireless Telegraph Company commercial design originally conceived for land-based air defence,[10] which was credited with a range of 70 nautical miles (130 km) at 35,000 feet (11,000 m).[1]
  • Extending the range of the Type 992 radar, by slowing its scanning rate.[1]

A potential route for the Royal Navy to get the SPS-6C was the Mutual Defense Assistance program (MDAP), but by 1954-5 the programme was running down.[10] 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.[1] The Marconi design was chosen and was named Type 965.[1] The Type 965M was introduced in about 1960, and used the original AKE(1) aerial with an improved receiver and feeder.[1]

Ships with Type 965 radars

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HMS Bacchante in June 1973, with the Type 965M radar's single bedstead AKE(1) aerial on her mainmast.
 
HMS Lincoln in 1972, with the Type 965P radar's double bedstead AKE(2) aerial on her mainmast.

Technical specifications

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A common aerial was used for transmitting and receiving.[2] This was the single bedstead AKE(1) in the Type 965M, and the double bedstead AKE(2) in the Type 965P.[2] The 965M and 965P were integrated with IFF Mk 10.[2] The radar displayed both to an "office display unit" (monitor unit design 44), and up to six remote plan position indicator (PPI) displays.[2]


Type 965M and 965P specifications
Type 965M and 965P [2][28][29] Type 965Q and 965R [3]
Frequency 216-224 MHz
Wavelength approximately 1.4 m (4 ft 7 in)
Power output 450 kW
Pulse repetition frequency (PRF) 200 or 400 pulses per second (p/s) nominal See below
Pulse width 3.8 μs (with 400 p/s PRF)
10 μs (with 200 p/s PRF)		 4 μs (nominal for MTI working)
10 μs (for non-MTI working)
Aerial rotation speed 10 revolutions per minute
Intermediate frequency 13.5 MHz
Aerial beam width 12° (horizontal), 40° (vertical)
Receiver bandwidth long pulse 120 kHz, short pulse 330 kHz long pulse 120 kHz, short pulse (MTI) 330 kHz
Differences between Type 960 and 965M
  • Type 965 receiver noise factor: 8 dB.[1]
  • Type 965M receiver noise factor: 4.5 dB.[1]
  • Type 965M feeder was 1 dB better than the Type 960 feeder.[1]
Range
  • Type 960: credited during appraisal as 70 nautical miles (130 km) at 35,000 feet (11,000 m).[1]
  • Type 960: 120 nautical miles (220 km) against an English Electric Canberra at 20,000 feet (6,100 m).[1]
  • Type 965M: 200 nautical miles (370 km) at 45,000 feet (14,000 m).[1]
  • Type 965P: 280 nautical miles (520 km) at 100,000 feet (30,000 m).[1]

Type 965Q and 965R

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The receiver of the Type 965Q and 965R used "a coherent oscillator (COHO) to provide the coherence in phase between transmission and reception. The COHO is phase locked to the transmitter pulse."[3] With the Type 965Q and 965R, the pulse repetition frequency (PRF) had a number of different settings.[3]

  • In non-MTI mode, the PRF was set by the Pulse Synchronising Outfit RSE.[3]
  • 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.[3]
    • 2580 μs pulse interval ±516 μs stagger time
    • 2590 μs pulse interval ±518 μs stagger time
    • 2600 μs pulse interval ±520 μs stagger time
    • 2610 μs pulse interval ±522 μs stagger time
    • 2620 μs pulse interval ±524 μs stagger time

Notes

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  1. ^ Woodward's book One Hundred Days (page 10) says that the initial detection was on the "UAA 1 console".[7] Hampshire's book British Guided Missile Destroyers (page 13) explains that Type 42 destroyers were equipped with "UAA1 (Abbey Hill)" from 1978, and says that this is a type of electronic warfare equipment it calls "intercepts", which "detect and identify the radars of approaching aircraft, ships and missiles."[9]

References

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  1. ^ a b c d e f g h i j k l m n o p q r s t Friedman, British Destroyers & Frigates, pp. 162, 176.
  2. ^ a b c d e f g "Type 965M/P Summary of Data, BR 333(1)" (PDF). marconiradarhistory.pbworks.com. Retrieved 2 June 2017.
  3. ^ a b c d e f g "Type 965Q/R Summary of Data, BR 333(1)" (PDF). HMS Collingwood Heritage Collection. Retrieved 17 June 2018.
  4. ^ "Type 960 Summary of Data, BR 333(1)" (PDF), www.rnmuseumradarandcommunications2006.org.uk, retrieved 3 June 2017
  5. ^ Friedman, British Cruisers, p. 319.
  6. ^ Rivas (2012), p. 244.
  7. ^ a b c Woodward & Robinson (1992), p. 10.
  8. ^ Middlebrook (2012), p. 156.
  9. ^ Hampshire (2016), p. 13.
  10. ^ a b c d Friedman, Innovation and Defence, pp. 255–256
  11. ^ Marriott, Royal Navy Aircraft Carriers, p. 65.
  12. ^ Jane's (1975), p. 360.
  13. ^ Jane's (1975), p. 359.
  14. ^ Marriott, Royal Navy Frigates, pp. 87, 94.
  15. ^ a b Marriott, Royal Navy Destroyers, p. 105.
  16. ^ Marriott, Royal Navy Aircraft Carriers, p. 96.
  17. ^ Dyson (1984), p. 85.
  18. ^ Friedman, British Destroyers & Frigates, p. 203.
  19. ^ Jane's (1966), p. 296.
  20. ^ Jane's (1975), p. 361.
  21. ^ a b Jane's (1982), p. 551.
  22. ^ Marriott, Royal Navy Aircraft Carriers, p. 61.
  23. ^ Marriott, Royal Navy Destroyers, p. 115.
  24. ^ Jane's (1975), p. 347.
  25. ^ Marriott, Royal Navy Aircraft Carriers, p. 68.
  26. ^ Jane's (1982), p. 553.
  27. ^ Marriott, Royal Navy Frigates, p. 118.
  28. ^ "Type 965M/P Summary of Data, BR 333(1)" (PDF). HMS Collingwood Heritage Collection. Retrieved 17 June 2018.
  29. ^ Jenkins, SR (14 January 2014). "Radar sets of the County Class". www.littlewars.org.uk. Retrieved 2 June 2017.

Publications

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