List of World War II British naval radar

This page is a List of World War II British naval radar.

Nomenclature
These sets were initially numbered as wireless telegraph (w/t) sets, but a distinguishing prefix of "2" was soon added. Metric sets were numbered in the 28x and 29x series. When centimetric sets arrived with the advent of the cavity magnetron, they were numbered by subtracting 10 from the metric type number they were based on (e.g. the metric Type 284 was replaced by the centimetric Type 274). This was not always possible however, as Types 271 - 274 were already in use for original centimetric sets, thus some metric sets in the Type 28x range had 20 subtracted (e.g. the metric Type 282 was replaced by the centimetric Type 262). Aerial outfits were given a three letter identifier that began with "A".

Suffixing letters indicated the following;
 * B - conversion of sets with separate transmitting (Tx) and receiving (Rx) antennas to single antenna operation.
 * M, P, Q - major set modifications
 * R - addition of range-taking panel
 * U - modification to suit coastal operations
 * W - modification to submarine use
 * X, Y, Z - experimental modifications

ASV II
The first successful Air to Surface Vessel (ASV) radar. ASV II radar allowed Aircraft Carrier based RN Swordfish to locate and attack the German battleship GERMAN BATTLESHIP Bismarck in May 1941, from the carriers HMS Victorious (R38) and HMS Ark Royal (91).

ASV III
The first successful airborne microwave radar. This radar was used on both the Swordfish and Barracuda aircraft. High resolution centimetric radar could detect even small objects, such as the periscope or snorkel of a submerged submarine, making it a highly efficient tool for ASW. The Mk XI was a further development exclusively for the Fleet Air Arm.

Type 79
Based on the Type 79 w/t, first fitted to HMS Sheffield (C24) then HMS Rodney (29) and later HMS Curlew (D42); (40 sets ordered)

Type 86
Fore-runner to Type 286.

Type 262
Centimetric fire-control set for 40 mm Bofors weapons. Fitted to Close Range Blind Fire (CRBF) director and STAAG weapon mount. Dish antenna spun off-centre at high speed to produce scanning cone, target lock and blind fire possible.

Type 267
Air warning set for submarines replacing Type 291W.

Type 268
Small vessel millimetric target indication and navigation.

Type 271
Type 271 was the original naval centimetric target indication radar, later fitted with a plan position indicator. Modifications P and Q were known as the "Centimetric Mark IV". It had separate transmit and receive aerials, small parabolic dishes stacked on top of each other, and referred to as "cheese" after their shape. The antenna array was carried in distinctive protective perspex "lantern", and initially had to be fitted directly onto the radar office roof due to limitations in coaxial cabling (until suitable waveguides had been developed.) The Type 271 was a vitally important war weapon, as for the first time it allowed escort ships to reliably detect surfaced U-boats or even just their periscopes. It was first fitted in HMS Orchis (K76). 350 sets were ordered. It was fitted widely to escort vessels of corvette and frigate size.

Type 272
"Centimetric Mark III" target indication set. Carried in distinctive protective perspex "lantern". For vessels of destroyer and cruiser size.

Type 273
"Centimetric Mark IV" target indication set. This set was based on the Type 271, but was intended for major warships of cruiser and battleship size. It used side-by-side 3 ft wide cheese antennas that were carried in a distinctive protective perspex "lantern". In the Battle of the North Cape, HMS Duke of York (17) identified the target of GERMAN BATTLESHIP Scharnhorst at 45000 yd using her Type 273 set.

Type 274
Centimetric replacement for Type 284. Main armament ranging and shot-spotting set for cruisers and battleships. "Double cheese" antennas.

Type 275
Centimetric replacement for Type 285. Destroyer main armament and capital ship secondary fire control set. Fitted to directors HACS Mark VI and Mark 6M and modified American Mark 37. Separate Tx and Rx dishes.

Type 276
"Centimetric Mark V" target indication set with continuously rotating antenna. Reduced 4 ft antennas in aerial outfit AUS.

Type 277
"Centimetric Mark V" target indication set with steerable antenna. Aerial Outfit AUK was a parabolic dish, ANU was a cropped paraboloid. Fitted on a "nodding" mount, often used as a height finding set. Superseded in service by Type 278 height finder in s.

Type 279
Follow on from Type 79, metric air warning set. Had separate Tx and Rx antennas, combined in Type 279M to single antenna operation. This set also had a secondary surface search with surface and aerial gunnery capability and used a Precision Ranging Panel, which passed accurate radar ranges directly to the HACS table (analog computer).

Type 280
Metric air warning set with separate Tx / Rx antennas. Based upon Army GL Mark I set, fitted to s converted to anti-aircraft ships. This set used a Precision Ranging Panel, which passed accurate radar ranges directly to the HACS table (analog computer).

Type 281
Metric air warning set with separate Tx / Rx antennas. Type 281B had combined Tx / Rx antenna. First fitted to HMS Dido (37) then HMS Prince of Wales (53) This set also had a secondary surface search and gunnery capability and used a Precision Ranging Panel. The Type 281 ranging system allowed the user to select either a 2000yd to 14000yd or a 2000yd to 25000yd range display with range accuracies of 50 or 75yds RMS, respectively.

Type 282
Centimetric ranging set for Bofors 40 mm and "multiple pom-pom" fire control. Fitted on Bofors mounting Mark IV "Hazemeyer" and "Pom-pom Director Mk IV", twin Yagi antennas. Type 282 used a mechanical ranging panel and a 0-5000yd display. Type 282M increased transmission power to 150KW, used a 0 - 6000yd display and introduced Beam Switching, while Type 282P introduced a Precision Ranging Panel.

Type 283
Main armament anti-aircraft barrage fire control set fitted to "barrage director" for cruiser 6 in and battleship guns. This set used a Precision Ranging Panel and was used to fire the guns automatically using the Automatic Barrage Unit.

Type 284
Main armament ranging and shot-spotting set for cruisers and battleships with lobe switching beginning with Type 284M to increase accuracy of bearing readings. Prototype fitted on HMS Sardonyx (H26). HMS Southdown (L25) received first production set. Used by HMS Suffolk (55) to shadow GERMAN BATTLESHIP Bismarck. Type 284P was instrumental in the Battle of the North Cape, effectively allowing HMS Duke of York (17) to sink GERMAN BATTLESHIP Scharnhorst blind.

Type 285
Ranging set for anti-aircraft fire control, fitted to HACS directors and rangefinder-directors and used ranging panel L12. Type 285 with six element Yagi antenna with separate Tx / Rx. Type 285P with five element Yagi antenna with combined Tx / Rx function. The Type 285M could provide accurate ranges via the mechanical ranging panel, L12, and bearing information using lobe switching, but height finding was primitive and had to be calculated using maximum signal indication. As such it could not achieve a target lock, and could not offer blind fire capability. Type 285P introduced a Precision Ranging Panel and had 25yd RMS range accuracy.

Type 286
Metric target indication set based upon RAF ASV (Air to Surface Vessel) Mark II set. Type 286M had fixed antennas, with a central Tx and an Rx on either side to give some indication of contact bearing. The antennas were fixed, scanning being achieved by conning the ship. Type 286PU and Type 286W were fixed antennas sets for coastal vessels and submarines respectively. Type 286PQ had a steerable combined Tx / Rx antenna from the Type 291 set.

Type 290
Metric target indication set, replacement for Type 286.

Type 291
Metric air warning sets. Original Type 291 had a hand-steered antenna, replaced by Type 291M with power training and plan position indicator. U and W variants for coastal craft and submarines respectively.

Type 293
"Centimetric Mark V" target indication set, shared transmitter with Type 276 / Type 277 sets. Stabilised "cheese" antenna, 6 ft diameter in outfit AUR, upgraded to 8 ft in Type 293P (replaced all Type 293 and Type 276 sets) and to 12 ft in Type 293Q.

Precision Ranging Panel
The Precision Ranging Panel (PRP) was an electromechanical transmission and calculating system. The PRP allowed for accurate range determination, range rate determination using radar, and accurate transmission of radar ranges and range rates to fire control computers. The PRP used an electronic timing signal and pip matching to provide very accurate ranges. It also used a power follow up to continuously transmit the correct range rate as long as the target maintained a steady course and speed. The PRP was adapted from the British Army GL, Gun Laying, radar system, and first went to sea in 1939 aboard several s, using the Type 280 radar. By 1941 the PRP was a common feature on the Type 280, 279 and 281 radars, and by late 1941 began to appear on the type 282P, 284P and 285P radar systems.

Mechanical Ranging Panel
The Type 282, 282M, 285, and 285M radars used a mechanical ranging panel that used a mechanical cursor placed over the ranging display, to estimate range and automatically transmitted the calculated range to either the HACS or FKC fire control computer. Type 285 used Ranging Panel L12 and this also featured range rate estimation with power follow up so that the ranging panel would continue to transmit the correct range without operator intervention as long as the target maintained a steady course at a constant speed.