Appendix: Type Numbers of Naval Radar Sets, Operational or Designed, 1935--45 Derek Howse IFF - Identification Friend or AI - Air interception Foe ASV - Air to surface vessel INT - Interrogator BCN -Beacon LA -Low angle CCA -Carrier Controlled Ap- Rg. - In the ranging mode proach (Types 279 and 281) FD - Fighter direction Rx -Receiver GA -Gunnery fire control, Sw. -sweeps aircraft, high angle (or TI - Target indication combined low angle Tx - Transmitter and high angle) WA - Warning of aircraft GB -Gunnery fire control, WC - Warning (combined air- barrage craft and surface) GC -Gunnery fire control, Wg. - In the warning mode close range, high angle (Types 279 and 281) GS -Gunnery fire control, WS - Warning of surface surface (i.e, low angle) craft HA - High angle :::::: - Variable around this Ht-fndr - Height-finder frequency In the numbering of Naval radar sets, the first, second and third major modifications to the basic set were indicated by the suffixes M, P and Q respectively, ego Type 286P. The suffix B indicated adaptation to single-mast working. Information not available is generally marked with a dash. 309 w Type Classifimtion Wavelength Freq. Power To sea ...... number nominal (MHz) (kW) (abandoned) Description 0 79 WA 75m 39-42 70 1938 Long range air warning for large shi ps. See 279. 79B WA 75m 39-42 70 1941 Single-masted version of 79 (originally 79M). 91 Jammer SOcm-3m 90-600 lQ--25w l 1941 Jamming of German metric and decimetric radar. Initially sine- wave modulation, ultimately noise . 241 INT 15m 214 - 1941 For use with 281 & IFF Mk 2N. 242 Int 15m 182 or 179 1 1943 For use with WS and WC sets and IFF Mk 3. 242M INT 15m 182 or 179 2-10 1943 Ditto 243 INT 15m 179 or 171 1 1943 For use with 281 & IFF Mk 3. 244 INT 15m - - 1943 For use wit h US Type SL & IFF Mk 3. 245 !NT 15 m -- 1944 For FD ships. 251/M/P BeN 15m 176 or 177 7 1942 Modified RAF transponder coded to give ships' identity. 252 IFF 15m 38-52 & - 1942 IFF Mk 2 in ships. 195-220 253/P IFF 15m Sw.157-187 10 1943 IFF Mk 3 in shi ps . Sweeps frequency. 253S IFF 15m Sw.157-187 10 1943 253 when fitted ashore. 255 BeN 15m 214 - 1944 Marker bu oy for use only wi th 291. 256 BeN 15m 214 - 1944 Shore radar beacon for use only with 291. 257 CCA 3cm - - 1945? Carrier controlled approach (BABS). 258 BeN 15m 179/182 - 1943 Mk 3 shore radar beacon responding to 242. 259 BeN 15m -- 1944 Mk 3 beacon for carriers responding to Al Mk 10. 261 WS 50cm -- (1941) Based on 282. 261W WS 3cm - - (1942) Early 3cm development, leading to 267W. 262 GC 3cm :::::: 9650 20 1945 STAAG, CRBFD 263 GB 3cm -- (1945) Au to-barrage for main or secondary armament, replacing 283. 267W/MW/PW WS/WC 3cm & ::::::9670 15-25 1945 Submarines. Hy brid WS/WC with common disp lay. 15m & 214 & 100 268 WS 3cm 9400 - 1945 For coastal forces, replacing 291U. 269 GS 3cm 10000 - (1943) Modified 3-em AI set for coastal forces gunnery . 271/M/P WS 10cm ~3000 5-lO 1941 Small ships. 271Q WS 10cm ~3000 70 1943 Small ships. 272/M/P WS 10cm ~3000 5-lO 1941 Small cruisers, carriers, sloops, etc. 273/M/P WS 10cm ~3000 5-10 1941 Large ships. 273Q WS lOcm ~3000 70 1943 Large ships. 274 GS lOcm ~3300 400 1944 Main armament directors, replacing 284. 275 GA lOcm 3530 400 1945 HA directors (HA/LA directors in destroyers), replacing 285. 276 WS lOcm 3000 500 1944 Small ships, replacing 271/2. 277/P/Q WS 10cm 3,000 500 1944 Replaced 271/2/3. Could measure approximate elevation. 277S WS/lowair lOcm 3000 SOO 1943 277 permanent shore installation for surface and low air. 277T WS/lowair lOcm 3000 500 1943 Trailer-mounted 277. 'Monrads'. 279 WA 75m 39-42 Wg.70 1940 Long-range air warning for large ships. Type 79 with gunnery Rg.6O ranging. 280 WA/GA 3.6m 82 25 1940 Based on Army GLl . In Carlisle and 'Bank' class ships only. 281 WA 35m 86-94 Wg.600 1940 Long-range air warning for large ships. Rg.l ,OOO 281B WA 35m 86-94 600 1943 Single-masted version of 28t. 281BM/BP/BQ WA 35m 86-94 350 1945 Continuous rotation. 282 GC 50cm ~600 15 1941 Porn-porn directors, etc. 282Ml/M2/M3 GC 50cm ~600 60 or 80 1942 Increased power. 282M4 GC 50cm ~600 60 or 80 1942 Beam-switching. 282Q GC 50cm ~600 150 - Beam-switching and increased power. 283/M GB 50cm ~600 150 1943 Auto-barrage for main or secondary armaments. 284/M/P GS 50cm ~600 As 282 1940 Main armament directors. 285/M/P/Q GA 50cm ~600 As 282 1940 HA directors (HA/LA directors in destroyers). 286M/P WC 15m 214 7 1940 Small ships. 286M fixed aerial, 286P revolving aerial 286PQ WC 15m 214 100 1943 Small ships. Higher power. 286U WC 15m 214 7 1941 Coastal forces. 286W WC 15m 214 7 1941 Submarines. 287 Minewatch 50cm ~600 15 1941 284 adapted for minewatching ashore. VJ 288(1) GC 50cm ~600 15 (1941) 284 adapted for Armed Merchant Cruisers. ...... ...... VJ Type Classification Wavelength Freq. Power To sea ..... number nominal (MHz) (kW) (abandoned) Description N 288(2) GC 5Dem ~600 15 - 284 adapted for training ashore. 289 GA 70cm ~430 - 1940 Dutch. Fitted in Isaac Sweers and Heemskerck only. 290 WC 15m 214 100 1941 Small ships, replacing 286 but abandoned in favour of 291. 291/M WC 15m 214 100 1941 Small ships, replacing 286/290. 291U WC 15 m 214 100 1943 Coastal forces. 291W WC 15m 214 100 1943 Submarines. 293/M WC/TI 10cm 3000 500 1944 Destroyers and above. Replaced 271/2/3. 294 WC/FD lOcm 3000 - (1944) Combined plan-display and heightfinding, replacing 277. 295 WC/FD lOcm 3000 - (1944) Higher-powered 294. 650 Jammer ~6m ~ 50 IG-20w 1944 Jamming of air-launched FX 1400 and HS 293 anti -ship guided weapons. Sine-wave mod ulation. 651 Jammer ~6m ~50 2 x lkw 1944 As Type 650 bu t capable of handling muIti- missile attack. CW mod ulation. 930 GS/splash I Dem 3000 7 1945 Splash-spotting; Naval version of Army CA No.1, Mk.5 ('William'). 931 GS/splash 1.25cm ~24000 - 1945 Splash-spotting, Canadian. 940/1 INT 15m 209 1 1944 G-band interrogator with 281BP/BQ. 951 BeN ---- Marker beacon for use with lOcm WS and WC sets . 952 BCN Rx 3cm Rx ~9400 - 1945 Portable combined ops . navigational. Triggered by X-band, Tx 15m Tx 182 response on Type 242. 960 WA 3.4m ~88 450 1946 Long-range air warning for large ships, replacing 281/79/279. 961 CCA 3cm ~9320 - - Carrier controlled approach. Modified ASV II. 970 WS 10cm ~3300 - 1943 Combined operations. Modified RAF H2S II. 971/M WS 3cm ~9320 - 1945 As 970 but based on H2S III. 972 WS 3cm ~9375 - 1946 Surveying. 980 WC/ FD 1Oem 3000 500 (1949) Fighter direction plan display, replacing 294/5. 981 Ht-fndr 10cm 3000 500 (1949) Fighter direction heightfinder, replacing 294/5. 990 WC 10cm 3000 - (1944) Low cover, to go wit h 960, 294/5. 992 TI IDem 3000 - 1959 Target indica tion, replacing 293. American sets fitted in British ships SA WA 15m 1943 Captain and Colony-class frigates . SG WS 10cm ~3195 1943 Escort carriers, Indomitable, Victorious. SJ WS 10cm 1945 Submarines Tiptoe and Trump. SK WA 15m 1943 Escort carriers. SL WS 10cm 1943 Cap tain and Colony-class frigates. SM-1 FD 10.7cm ~ 2 800 1944 Carriers Indomitable, Ocean; FD ships Boxer, Palomares. SO WS 10cm 1944 Coas tal forces, SQ WS 12cm 1945 Big ships' portable 'after-action' set. Naval Airborne Radar ASV Mk.II ASV 15 m 176 - 1940 Standard RAF versio n. ASV Mk.IIN ASV 15m 214 7-22 1941 Nava l versio n of ASV II. Swordfish, Walrus, Albacore, Barracuda ASV Mk.XI ASV 3cm - 35-50 1943 Swordfish III, Barracud a III. ASB ASV 15 m 214 - 1944 US copy of ASV lIN. Avenger. ASH ASV/AI 3cm ~9375 35 1944 US A NIAPS-4. Avenger, Firefly. Barracuda V. AI Mk.IV AI 15m - 10 1944 Fulmar. AlA AI 3cm - - 1945 US ANIAPS-6. Hellcat. Principal source: Adm iralty, CB 4497, Simple Guide to Naval Radar (1949) . w ...... I Depending upon frequ ency. w Glossary of Technical Terms and Abbreviations Used in This Work AA Anti-aircraft AB Able Seaman ABU Auto-barrage unit for radar-controlled blind-fire ACNS Assistant Chief of Naval Staff Acorn valve A small high-frequency valve about 'l-In in diameter shaped like an acorn, with the leads arranged radially around the middle of the envelope ADEE Air Defence Experimental Establishment (Army) Admiralty Divisions of the Naval Staff were responsible for operational organization matters, such as the Operations, Plans, Training and Staff Duties, and Naval Intelligence Divisions, reported to the First Sea Lord through the Deputy and Assistant Chiefs of Naval Staff. Admiralty Departments generally responsible for materiel matters, such as the Naval Ordnance, Naval Construction, Scientific Research, and Signals Departments, reported to the Controller. Operational sections of the Signal Department and the Naval Ordnance Department were in London, materiel sections in Bath from the outbreak of war ADP Air Defence Position ADR Aircraft Direction Room ADRDE Air Defence Research and Development Establishment (Army) (formerly ADEE, qv) AFC Automatic Frequency Control AFCC Admiralty Fire Control Clock AFCT Admiralty Fire Control Table AFO Admiralty Fleet Order AGC Automatic Gain Control, in a receiver AGE Admiralty Gunnery Establishment AI Air interception (airborne radar) AIC Action Information Centre AIO Action Information Organization AITC Action Information Training Centre A/I Anti-jamming (techniques) AMRE Air Ministry Research Establishment, later the Telecommunica­ tions Research Establishment ANCXF Allied Naval Commander-in-Chief Expeditionary Force AOP Angle of presentation (of an aircraft target) AOR Air Operations Room ARL Admiralty Research Laboratory ARM Availability, Reliability, Maintainability (of electronic equip­ ment) ARP Auto-radar plot A/S Anti-submarine A-scan See Display ASCBS Admiral Superintendent, Contract-Built Ships 315 316 Glossary Asdic Underwater detection equipment using acoustic waves .