183:
389:
499:
231:
614:
239:
585:
560:, which was cleared for service use in 1958, and came into operational use in the Shackleton Mk 2 and 3 beginning in 1959. ASV21 could detect a submarine schnorkel at 15 nautical miles (28 km) "in very favourable conditions but at much shorter range in the sea states normally experienced in the North Atlantic." ASV21 was generally similar to the earlier designs. ASV21 was also selected for the Mark II models of the
222:. This amplified the radar's pulses and played them into the radio operator's headphones. It provided this warning long before the echos from the submarine became visible on the aircraft's display. With experience, the operators could tell whether the aircraft was approaching or just flying by, allowing the U-boat to dive and escape detection. By the end of 1942, Mark II had been rendered ineffective.
114:
365:
approached the U-boat, hopefully fooling the radio operator into believing they were flying away. Mark VI never fully replaced Mark III in service, as truly effective detectors did not become available until the U-boat fleet had largely been destroyed. The failure of Naxos and later devices led to morale problems in the U-boat force.
286:'s began arriving in March 1943, and had largely replaced the Mark II in front-line units by the end of the summer. The Germans had no way to detect these signals, and their submarines were repeatedly attacked with no warning. The losses were so great they took to leaving port in the day, but the RAF responded with
302:
The reason for the long delay in discovering Mark III is somewhat surprising given that a magnetron from H2S fell into German hands almost immediately after it was first used in
February 1943. Sources disagree on the reason; the magnetron was either unknown to the German Navy, or they did not believe
298:
that allowed them to detect the submarines at as much as 90 miles (140 km). This led to an urgent 13 August 1943 message from German Naval High
Command ordering that submarines turn off their Metox. This incredible deception not only further delayed the German discovery of the true nature of the
196:
For a variety of reasons, the 1.5 m wavelength of the radar system worked better over water than land, and the large size and flat vertical sides of the ships made excellent radar targets. Production quality sets were available in 1939 and entered operational service in early 1940, becoming the
517:
Adding to the problem was the loss of the large numbers of
Liberator aircraft with the ending of lend-lease. These had been used as very long-range patrol aircraft during the war, and their return to the US left Coastal Command with no suitable airframes to cover the GIUK gap. A solution was found
647:
and being the first generation of ASV radars to include modern signal and data processing (digital as well as analogue)". This gave
Searchwater a better ability than ASV13 or ASV21 to detect small targets such as submarine periscopes against a background of strong sea returns. The radar screen for
360:
was unsuitable for bombing operations, the Air
Ministry ordered Coastal Command to take over their existing orders in spite of them having a shorter range that was unsuitable for closing the Gap. Coastal Command was able to have the radar switched to the ASG, which they operated under the name ASV
293:
The
Germans spent much of the rest of the year using radar detectors at longer wavelengths in a fruitless attempt to find the new ASV. Further confusion was added by a captured Coastal Command pilot, who related that ASV was no longer used for search, but only in the last minutes of the approach.
550:) of about 40 nautical miles (74 km) for a destroyer, 20 nautical miles (37 km) for a surfaced submarine, and 8 nautical miles (15 km) for a submarine conning tower. "In rougher conditions, the range would be much less." By 1958, ASV13 was considered "old and rather unreliable".
364:
The TRE was sure the
Germans would soon detect Mark III and render it ineffective as well, so they responded with a new ASV Mark VI that was essentially a more-powerful Mark III. The key trick to Mark VI was the "Vixen" device that allowed the operator to progressively mute the output as they
209:
that lit up the submarines during the last seconds of the approach. By early 1942, Mark II and the Leigh Light were finally available on large numbers of aircraft. Their effect was dramatic; German U-boats had previously been almost completely safe at night, and could operate out of the
200:
These designs had a relatively long minimum range, meaning the submarine targets disappeared from the display just as the aircraft was readying for the attack. At night, this allowed the submarines to escape attack by maneuvering when an aircraft could be heard. This was solved by the
592:
The war-era radar classifications became less relevant in the 1970s as radar units increasingly became multi-purpose as opposed to being single-role. Newer designs, even dedicated naval surveillance designs, were not assigned numbers in the ASV lineage. The first such example is the
332:
in a matter of weeks. US development was not subject to the infighting in the RAF, but suffered its own series of setbacks and confusion. The early DMS-1000 proved to be an excellent unit, but for reasons unknown, the US War
Department decided to put the inferior
158:
was hand held outside one of the escape hatches and rotated looking for when the signal disappeared, indicating the antenna was aligned with the target ship. This was not easy as the signal naturally fluctuated. The first successes were in August 1937.
311:
to track the RAF's H2S radars. Naxos provided very short detection range, about 8 kilometres (5.0 mi), too short to be really useful. Better detectors arrived very late in the war, but by that time the U-boat force had largely been destroyed.
483:. This was a very simple system originally intended to indicate a selected range to the pilot, which proved very useful for timing bomb drops. Trials were carried out in August 1944 and experimental fits were made to the Beaufighter, Mosquito and
214:
in spite of it being close to
British shores. By the spring of 1942, Biscay was increasingly dangerous, with aircraft appearing out of nowhere in the middle of the night, dropping bombs and depth charges, and then disappearing again in moments.
380:, while the US version based on ASG was known as AN/APS-15 and given the UK designation ASV Mark X. It was expected the latter would be available in December 1943. The similar AN/APS-3 was mounted to Catalinas and named ASV Mark VIII.
545:
so the image did not change when the aircraft manoeuvred, and the use of a pressurised radome that kept out humidity and made it suitable for use in tropical areas. ASV13 was a centimetric radar with a detection range in a calm sea
609:
at long range from their carrier ships. It has since been sold around the world and used in a variety of roles. The latest versions, Seaspray 7000, are completely rebuilt and share only the name with the original models.
49:
in 1937. For a variety of reasons, ASV was easier to develop than the air-to-air variety of the same systems, and the first operational use of the Mark I followed in early 1940. A cleaned-up and repackaged version,
197:
first radar system to be mounted on an aircraft in a combat setting. A somewhat improved version, Mark II, followed in 1941, which saw tens of thousands of units produced in the UK, Canada, US and
Australia.
475:, had the problem that the fitting of ASV required the removal of some other devices to make room. Previously they had carried a long-distance radio for remaining in contact with their base, as well as a
30:(RAF) to refer to a series of aircraft-mounted radar systems used to scan the surface of the ocean to locate ships and surfaced submarines. The first examples were developed just before the opening of
479:
system for navigation. Neither could be safely removed, and the desire for a much smaller ASV for this role developed. This was fulfilled with the Mark XVI, built in the US as LHTR and supplied under
396:
In October 1944, the Germans introduced two innovations that were extremely worrying. One was the introduction of new classes of U-boats with much higher performance, and the other was the use of the
356:, and an example of this aircraft with the DMS-1000 was sent to the UK for testing in early 1942. Another 30 arrived with a mix of DMS-1000, SCR-517 and ASG. However, when Bomber Command decided the
256:
in early 1940 led to efforts to develop microwave-frequency versions of the various radars then in use, including a new ASV under the name ASVS for "Sentimetric". A prototype was available from
368:
Another solution to the problem of being detected was to change frequencies. From 1943, both the UK and US began developing magnetrons that worked on even shorter wavelengths, first in the
625:, which was designed to replace the Mk. 21 in a new version of the Nimrod, the MR2. These began arriving in 1979. In 1978, the Royal Navy retired its fleet carriers, losing the
77:, which the Germans were unable to detect until the U-boat fleet had already been decimated. A series of other ASVs were developed for different aircraft as the war progressed.
409:
On 22 November 1944, it was decided to deploy new 3 cm-band ASV's, with both the UK and US developing versions. However, these demonstrated poor performance against the
162:
After several successful flights over the summer, Watt asked the team if they could be ready for a demonstration in September. On 4 September, the system was used to detect
348:
The RAF decided that UK-built aircraft would be fitted with their Mk. III, while any US aircraft in British service would use US sets. Initially, they planned on using the
402:, allowing even older types to spend most of their time submerged. This made the X-band versions of ASV a requirement, as they had the resolution needed to detect the
127:
Development of the original ASV systems started in 1937 after the team testing an experimental air-to-air radar noticed odd returns while flying near the shore of the
290:
patrols and losses shot up once again. In August, shipping losses to submarines was the lowest since November 1941, and more U-boats were sunk than cargo ships.
514:
led to a rapid re-evaluation of this stance, especially as the Soviets were known to be introducing new submarines surpassing even the late-war German designs.
1297:
1203:
1133:
413:, and experiments with these new systems were still underway when the war ended. In the immediate post-war era, development of the system continued as an
234:
The Mark III's small antenna was installed in a well-streamlined radome on the nose of the Wellington, forcing the removal of the guns in that location.
166:
ships on manoeuvres in almost complete overcast. The weather was so bad they had to use the radar pattern from local sea-side cliffs to navigate home.
65:
with rapidly increasing success. As German U-boat losses shot up in 1942, they concluded the RAF was using radar to detect them and responded with the
1431:
Smith, R.A.; Hanbury-Brown, Robert; Mould, A.J.; Ward, A.G.; Walker, B.A. (October 1985). "ASV: the detection of surface vessels by airborne radar".
1515:
736:
377:
636:
helicopter that was able to operate from a variety of ships. Several greatly improved versions followed, part of the Searchwater 2000 series.
557:
538:
527:
89:
85:
81:
242:
With the radome of the Mark III well streamlined, the Leigh light installation was also cleaned up by placing it in a retractable "dustbin".
1158:
were rapidly converted first for air-sea rescue duties and then, with the addition of ASV 13 radar, to the general reconnaissance role."
510:
in 1945, the British believed another war was at least a decade off, and put little effort into new radar systems. The opening of the
92:. By the late 1960s the original terminology was no longer being used, and the last major entries in the series were known simply as
1392:
Watching the skies: a history of ground radar for the air defence of the United Kingdom by the Royal Air Force from 1946 to 1975
643:, which was a technology developed during World War II. "Searchwater was a completely new concept, having a high power wideband
182:
648:
Searchwater could be viewed in daylight, unlike the screen of ASV21, which was viewed in a radar 'tent' on board the aircraft.
568:
of the Argus Mark I's. The Argus was widely described as the best anti-submarine aircraft of its era. ASV21D also equipped the
1400:
1180:
432:, which had previously used the early Mark II radars, the Mark X was further adapted as the Mark XI. This used a new narrow
1491:
1470:
1421:
1379:
1353:
576:
in the Nimrod MR 2 starting in 1980. ASV 21 remained in service on the Argus until the last example retired in 1981.
759:
ASV Mark X - RAF name for US ASD-1/APS-15 X-band system; used primarily on Liberators; not to be confused with ASVX
725:
ASV Mark VIA - added lock-follow which could direct the Leigh light, a separate pilot indicator, and blind-bombing
617:
Radar returned to the nose in the Nimrod, with this MR2 showing no outward sign of the Searchwater radar within.
686:
Mark IIIB - Mk. IIIA with internal modifications allowing the same unit to be used by Coastal or Bomber command
777:
ASV Mark XIII - modified Mk. XI for Mosquito, Beaufighter and Brigand; did not enter service before war ended
632:
aircraft. A new version of Searchwater, the LAST, was created to provide this coverage when mounted under a
174:
later commented that "This, had they known, was the writing on the wall for the German Submarine Service."
792:
ASV Mark XV - miniaturized version of XI; did not enter service but acted as the basis for future designs
357:
349:
448:
rockets with armor-piercing warheads to damage or puncture the U-boat making it impossible to dive, and
132:
502:
The Shackleton MR2 moved its Mark 13 radar to the ventral position in a well-streamlined installation.
498:
388:
135:
miles south of them. Shipping also appeared, but the team was unable to test this very well as their
1510:
767:
ASV Mark XI - originally known as ASVX, X-band design for Barracuda but used primarily on Swordfish
329:
45:
The first ASV was developed after the accidental detection of wharves and cranes while testing an
629:
569:
295:
1236:
260:
in the summer of 1942, but they predicted it would not be widely available until summer 1943.
61:
at night, but the target had to be seen to be attacked, a problem that was addressed with the
561:
457:
1272:
230:
54:, replaced it at the end of the year, but the system was not widespread until late in 1941.
304:
264:
219:
167:
151:
136:
66:
39:
8:
644:
626:
461:
303:
it could be used against U-boats. It was not until late 1943 that a naval version of the
276:
747:
ASV Mark VIII - RAF name for US AN/APS-3 radars; used mainly on Catalinas from June 1944
739:- largely similar to Mk. III but operating in the X-band at 3 cm; not widely used
272:
143:
1487:
1483:
Airborne Maritime Surveillance Radar: Volume 2, Post-War British ASV Radars 1946-2000
1466:
1417:
1396:
1375:
1349:
1308:
1214:
1176:
1144:
1119:
Airborne Maritime Surveillance Radar: Volume 2, Post-War British ASV Radars 1946-2000
771:
633:
606:
573:
547:
397:
1462:
Airborne Maritime Surveillance Radar: Volume 1, British ASV Radars in WWII 1939-1945
1032:
Airborne Maritime Surveillance Radar: Volume 1, British ASV Radars in WWII 1939-1945
988:
Airborne Maritime Surveillance Radar: Volume 1, British ASV Radars in WWII 1939-1945
1440:
1364:
690:
613:
594:
476:
429:
353:
334:
267:
suggested a new ASV could be quickly introduced by making minor changes to the new
253:
171:
97:
218:
The Germans ultimately solved the problem of Mark II with the introduction of the
1481:
1460:
1411:
1390:
1343:
805:
781:
534:
487:
465:
287:
238:
35:
27:
186:
The antenna array of the Mark II was quite large and produced considerable drag.
1155:
796:
542:
523:
519:
472:
414:
325:
155:
1504:
1444:
1312:
1218:
1148:
801:
ASV Mark 19A - made by Echo for the Royal Navy Gannet and Sea Prince aircraft
672:
ASV Mark IIA - Mk. II with more powerful 100 kW transmitter; 12 produced
598:
588:
Seaspray on the Lynx was an export success, seen here in the Royal Thai Navy.
484:
376:
at 1.25 cm. The UK-developed 3 cm version for the Liberator became
373:
321:
308:
211:
722:- high-power Mk. III with 200 kW magnetron, "Vixen", and stabilization
584:
42:
classification, which includes similar radars in ground and ship mountings.
677:
533:
A more suitable custom-built patrol aircraft was a priority and led to the
507:
453:
437:
283:
247:
74:
31:
1074:
1062:
1006:
711:- RAF name for US APG (AN/APS-2) radars used on Liberators and Fortresses
839:
750:
719:
698:
666:
622:
422:
206:
202:
191:
93:
62:
51:
1171:
McLelland, Tim (ed.), "Avro Shackleton, the RAF's Cold War Sub Hunter",
1319:
708:
660:
480:
163:
147:
117:
680:- centimetric radar based on H2S; widely used from March 1943 onwards
452:
to mark the location for follow-up attacks by other aircraft carrying
392:
The Swordfish mounted the ASV Mark XI radome between its landing gear.
804:
ASV Mark 21 - new design by EMI used on Canadair CP-107 Argus Mk II,
640:
565:
418:
268:
257:
128:
70:
526:
had become passé by this point, and these units were referred to as
456:. Further developments of this system led to the Mark XIII, used on
80:
In the post-war era, several new ASV radars were developed, notably
754:
702:
602:
511:
113:
46:
131:. They eventually realized these were the docks and cranes at the
441:
299:
problem but also allowed Mark II to once again become effective.
294:
Instead, their aircraft were using a receiver tuned to the Metox
263:
It was at this point that the Metox started to become effective.
795:
ASV Mark XVI - RAF name for US LHTR, a range-only unit used by
522:
bombers with Mark VII to become the Lancaster GR.3. The use of
471:
The Beaufighter, which became one of Coastal Command's primary
433:
369:
338:
271:, mostly to the antenna. This started a furious debate between
58:
1365:"H2S Radar in Bomber Command and ASV Radar in Coastal Command"
1175:, no. Icons No 21, Key Publishing Ltd, pp. 20, 33,
449:
342:
1430:
1325:
1080:
1068:
1012:
935:
845:
572:
when it came into service in 1970, and was replaced by the
445:
1086:
307:
arrived, having originally been developed to allow German
964:
553:
150:
that were able to fly out over the North Sea from nearby
123:
demonstrated ASV in commanding fashion in September 1937.
1372:
Canadians on Radar: Royal Canadian Air Force 1940 - 1945
954:
952:
950:
1050:
1038:
994:
947:
683:
Mark IIIA - improved version available from late 1943
1230:
1228:
923:
911:
899:
887:
875:
811:
ASV Mark 21D - modified version fitted to Nimrod MR1
742:
ASV Mark 7A - post-war version used on Lancaster GRs
601:. This was originally developed in concert with the
1197:
1195:
1193:
1191:
1098:
863:
705:; largely withdrawn by late 1943 in favour of Mk. V
345:, the ASG, which was much better than the SCR-517.
851:
827:
663:- 1.5 m VHF, 300 prototype sets built in 1940
444:impossible, so these aircraft were fit with eight
1225:
669:- production version of Mark I; ~23,000 produced
1502:
1188:
728:ASV Mark VIB - production version of the Mk. VIA
1110:
1025:
1023:
1021:
981:
979:
731:ASV Mark VIC - version of Mk. VI for Sunderland
440:. The radome's location made the carriage of a
1241:The Shackleton Association (thegrowler.org.uk)
541:. The main improvements were the addition of
275:, who wanted every H2S for their bombers, and
597:, a small unit designed to be mounted on the
34:and they have remained a major instrument on
1018:
976:
337:SCR-517 into production instead. Meanwhile,
1266:
1264:
1262:
1260:
1258:
1256:
1237:"Ballykelly – The Shackleton Era 1952-1971"
282:After several changes in policy, the first
26:for short, is a classification used by the
1305:Royal Air Force Historical Society Journal
1277:Defence Electronics History Society (DEHS)
1211:Royal Air Force Historical Society Journal
1204:"Maritime Patrol in the Piston Engine Era"
1166:
1164:
1141:Royal Air Force Historical Society Journal
1134:"Maritime Patrol in the Piston Engine Era"
372:at 3 cm wavelength, and later in the
352:, which had the range to operate over the
315:
279:, who wanted them for submarine hunting.
38:since that time. It is part of the wider
1362:
1253:
941:
780:ASV Mark 13A - post-war version used on
762:ASV Mark XA - APS-5A, minor improvements
612:
583:
537:. The Shackleton Mk 1 and 2 mounted the
497:
493:
387:
383:
237:
229:
181:
112:
1295:
1161:
1503:
1409:
1270:
1056:
1044:
1000:
970:
958:
929:
917:
905:
893:
881:
753:- RAF name for US ASH, later known as
1516:Military radars of the United Kingdom
1479:
1458:
1413:Echoes of War: The Story of H2S Radar
1388:
1341:
1201:
1170:
1131:
1116:
1104:
1092:
1029:
985:
869:
857:
833:
808:, and retrofitted to Shackleton Mk 2,
579:
328:, and local development began at the
69:. The RAF responded by deploying the
605:missile to allow the Lynx to attack
103:
1273:"2018 Russell Burns Spring Lecture"
530:, remaining in service until 1954.
518:by adapting surplus Bomber Command
13:
1452:
714:ASV Mark VA - improved ASG.3/APS-2
320:The magnetron was revealed to the
108:
14:
1527:
436:that fit between the Swordfish's
341:had been developing a system for
154:. The testing was crude; a small
139:was forbidden to fly over water.
1234:
177:
1335:
1289:
1125:
774:for Beaufighter strike fighters
651:
1:
1342:Bowen, Edward George (1998).
815:
421:even if they did not carry a
142:To further test the concept,
57:ASV was useful for detecting
1480:Watts, Simon (August 2018).
1459:Watts, Simon (August 2018).
820:
20:Radar, Air to Surface Vessel
7:
1370:. In Grande, George (ed.).
1271:Bruton, Liz (6 July 2018),
570:Hawker Siddeley Nimrod MR 1
417:system, as it could detect
358:Boeing B-17 Flying Fortress
350:Consolidated B-24 Liberator
225:
146:provided the team with two
10:
1532:
245:
189:
1486:. Morgan & Claypool.
1465:. Morgan & Claypool.
564:, replacing the American
556:developed a replacement,
1445:10.1049/ip-a-1.1985.0071
1410:Lovell, Bernard (1991).
770:ASV Mark XII - modified
689:Mark IIIC - Mk. III for
428:In order to upgrade the
330:MIT Radiation Laboratory
252:The introduction of the
16:RAF radar classification
1363:Campbell, W.P. (2000).
621:Another example is the
316:Other WWII developments
1173:Aeroplance Illustrated
789:ASV Mark XIV - unknown
701:- RAF name for the US
656:From Watts and Smith:
630:airborne early warning
618:
589:
503:
458:de Havilland Mosquitos
393:
296:intermediate frequency
243:
235:
187:
124:
1296:Coleman, Ian (2005).
1154:This says that "some
1095:, pp. 22–23, 35.
784:, and Shackleton Mk 2
639:ASV13 and ASV21 used
616:
587:
562:Canadair CP-107 Argus
501:
494:Post-war developments
391:
384:Late-war developments
241:
233:
185:
116:
1389:Gough, Jack (1993).
1202:Tyack, Bill (2005).
1132:Tyack, Bill (2005).
462:Bristol Beaufighters
305:Naxos radar detector
265:Robert Hanbury Brown
220:Metox radar detector
168:Albert Percival Rowe
152:RAF Martlesham Heath
137:Handley Page Heyford
67:Metox radar detector
40:surface-search radar
1121:. pp. 2-1–2-7.
973:, pp. 165–167.
627:Fairey Gannet AEW.3
558:ASV Mark 21 (ASV21)
539:ASV Mark 13 (ASV13)
506:With the ending of
324:in 1940 during the
277:RAF Coastal Command
1213:(33): 73, 75, 80.
944:, p. XVII-10.
693:using two scanners
619:
590:
580:Later developments
504:
394:
273:RAF Bomber Command
244:
236:
188:
144:Robert Watson-Watt
125:
1433:IEE Proceedings A
1402:978-0-11-772723-6
1326:Smith et al. 1985
1182:978-1-910415-22-1
1081:Smith et al. 1985
1069:Smith et al. 1985
1013:Smith et al. 1985
846:Smith et al. 1985
772:AI Mk. VIII radar
634:Westland Sea King
607:fast attack craft
574:Searchwater radar
104:WWII developments
1523:
1497:
1476:
1448:
1427:
1406:
1385:
1369:
1359:
1329:
1323:
1317:
1316:
1302:
1293:
1287:
1286:
1285:
1283:
1268:
1251:
1250:
1249:
1247:
1232:
1223:
1222:
1208:
1199:
1186:
1185:
1168:
1159:
1152:
1138:
1129:
1123:
1122:
1114:
1108:
1102:
1096:
1090:
1084:
1078:
1072:
1066:
1060:
1054:
1048:
1042:
1036:
1035:
1027:
1016:
1010:
1004:
998:
992:
991:
983:
974:
968:
962:
956:
945:
939:
933:
927:
921:
915:
909:
903:
897:
891:
885:
879:
873:
867:
861:
855:
849:
843:
837:
831:
466:Bristol Brigands
430:Fairey Swordfish
354:Mid-Atlantic Gap
335:Western Electric
254:cavity magnetron
172:Tizard Committee
47:air-to-air radar
1531:
1530:
1526:
1525:
1524:
1522:
1521:
1520:
1511:Aircraft radars
1501:
1500:
1494:
1473:
1455:
1453:Further reading
1424:
1403:
1382:
1367:
1356:
1338:
1333:
1332:
1324:
1320:
1300:
1294:
1290:
1281:
1279:
1269:
1254:
1245:
1243:
1233:
1226:
1206:
1200:
1189:
1183:
1169:
1162:
1156:Lancaster Mk 3s
1153:
1136:
1130:
1126:
1115:
1111:
1103:
1099:
1091:
1087:
1079:
1075:
1067:
1063:
1055:
1051:
1043:
1039:
1028:
1019:
1011:
1007:
999:
995:
984:
977:
969:
965:
957:
948:
940:
936:
928:
924:
916:
912:
904:
900:
892:
888:
880:
876:
868:
864:
856:
852:
844:
840:
832:
828:
823:
818:
806:Shackleton Mk 3
797:strike fighters
782:Shackleton Mk 1
654:
645:TWT transmitter
582:
535:Avro Shackleton
496:
473:strike fighters
386:
318:
288:strike aircraft
250:
228:
194:
180:
111:
109:Initial concept
106:
36:patrol aircraft
28:Royal Air Force
17:
12:
11:
5:
1529:
1519:
1518:
1513:
1499:
1498:
1492:
1477:
1471:
1454:
1451:
1450:
1449:
1439:(6): 359–384.
1428:
1422:
1407:
1401:
1386:
1380:
1360:
1354:
1337:
1334:
1331:
1330:
1318:
1288:
1252:
1224:
1187:
1181:
1160:
1124:
1117:Watts (2018).
1109:
1097:
1085:
1083:, p. 384.
1073:
1071:, p. 377.
1061:
1059:, p. 247.
1049:
1047:, p. 246.
1037:
1034:. p. 8-3.
1030:Watts (2018).
1017:
1015:, p. 371.
1005:
1003:, p. 166.
993:
990:. p. 8-2.
986:Watts (2018).
975:
963:
961:, p. 165.
946:
934:
932:, p. 163.
922:
920:, p. 159.
910:
908:, p. 158.
898:
896:, p. 157.
886:
884:, p. 156.
874:
872:, p. 209.
862:
850:
848:, p. 360.
838:
825:
824:
822:
819:
817:
814:
813:
812:
809:
802:
799:
793:
790:
787:
786:
785:
775:
768:
765:
764:
763:
757:
748:
745:
744:
743:
734:
733:
732:
729:
726:
717:
716:
715:
706:
696:
695:
694:
687:
684:
675:
674:
673:
664:
653:
650:
581:
578:
524:Roman numerals
520:Avro Lancaster
495:
492:
415:air-sea rescue
385:
382:
326:Tizard Mission
317:
314:
309:night fighters
246:Main article:
227:
224:
190:Main article:
179:
176:
156:dipole antenna
110:
107:
105:
102:
15:
9:
6:
4:
3:
2:
1528:
1517:
1514:
1512:
1509:
1508:
1506:
1495:
1493:9781643270692
1489:
1485:
1484:
1478:
1474:
1472:9781643270661
1468:
1464:
1463:
1457:
1456:
1446:
1442:
1438:
1434:
1429:
1425:
1423:9780852743171
1419:
1416:. CRC Press.
1415:
1414:
1408:
1404:
1398:
1394:
1393:
1387:
1383:
1381:9780968759608
1377:
1373:
1366:
1361:
1357:
1355:9780750305860
1351:
1348:. CRC Press.
1347:
1346:
1340:
1339:
1327:
1322:
1314:
1310:
1306:
1299:
1292:
1278:
1274:
1267:
1265:
1263:
1261:
1259:
1257:
1242:
1238:
1235:Hill, David,
1231:
1229:
1220:
1216:
1212:
1205:
1198:
1196:
1194:
1192:
1184:
1178:
1174:
1167:
1165:
1157:
1150:
1146:
1142:
1135:
1128:
1120:
1113:
1107:, p. 43.
1106:
1101:
1094:
1089:
1082:
1077:
1070:
1065:
1058:
1053:
1046:
1041:
1033:
1026:
1024:
1022:
1014:
1009:
1002:
997:
989:
982:
980:
972:
967:
960:
955:
953:
951:
943:
942:Campbell 2000
938:
931:
926:
919:
914:
907:
902:
895:
890:
883:
878:
871:
866:
860:, p. 45.
859:
854:
847:
842:
836:, p. 38.
835:
830:
826:
810:
807:
803:
800:
798:
794:
791:
788:
783:
779:
778:
776:
773:
769:
766:
761:
760:
758:
756:
752:
749:
746:
741:
740:
738:
735:
730:
727:
724:
723:
721:
718:
713:
712:
710:
707:
704:
700:
697:
692:
688:
685:
682:
681:
679:
676:
671:
670:
668:
665:
662:
659:
658:
657:
649:
646:
642:
637:
635:
631:
628:
624:
615:
611:
608:
604:
600:
599:Westland Lynx
596:
586:
577:
575:
571:
567:
563:
559:
555:
551:
549:
544:
543:stabilization
540:
536:
531:
529:
525:
521:
515:
513:
509:
500:
491:
489:
486:
485:Fleet Air Arm
482:
478:
474:
469:
467:
463:
459:
455:
454:depth charges
451:
447:
443:
439:
435:
431:
426:
424:
420:
416:
412:
407:
405:
401:
400:
390:
381:
379:
375:
371:
366:
362:
359:
355:
351:
346:
344:
340:
336:
331:
327:
323:
322:United States
313:
310:
306:
300:
297:
291:
289:
285:
280:
278:
274:
270:
266:
261:
259:
255:
249:
240:
232:
223:
221:
216:
213:
212:Bay of Biscay
208:
204:
198:
193:
184:
178:Mark I and II
175:
173:
169:
165:
160:
157:
153:
149:
145:
140:
138:
134:
133:Harwich docks
130:
122:
119:
115:
101:
99:
95:
91:
87:
83:
78:
76:
72:
68:
64:
60:
55:
53:
48:
43:
41:
37:
33:
29:
25:
21:
1482:
1461:
1436:
1432:
1412:
1391:
1371:
1344:
1336:Bibliography
1321:
1304:
1291:
1280:, retrieved
1276:
1244:, retrieved
1240:
1210:
1172:
1140:
1127:
1118:
1112:
1100:
1088:
1076:
1064:
1052:
1040:
1031:
1008:
996:
987:
966:
937:
925:
913:
901:
889:
877:
865:
853:
841:
829:
737:ASV Mark VII
678:ASV Mark III
655:
638:
620:
591:
552:
532:
516:
508:World War II
505:
470:
438:landing gear
427:
410:
408:
403:
398:
395:
378:ASV Mark VII
367:
363:
347:
319:
301:
292:
284:ASV Mark III
281:
262:
251:
248:ASV Mark III
217:
199:
195:
161:
141:
126:
120:
79:
75:ASV Mark III
56:
44:
32:World War II
23:
19:
18:
1057:Lovell 1991
1045:Lovell 1991
1001:Lovell 1991
971:Lovell 1991
959:Lovell 1991
930:Lovell 1991
918:Lovell 1991
906:Lovell 1991
894:Lovell 1991
882:Lovell 1991
751:ASV Mark IX
720:ASV Mark VI
699:ASV Mark IV
667:ASV Mark II
652:System list
623:Searchwater
548:Sea State 1
528:ASV Mark 7A
423:transponder
207:searchlight
203:Leigh Light
192:ASV Mark II
148:Avro Ansons
94:Searchwater
90:ASV Mark 21
86:ASV Mark 13
82:ASV Mark 7A
73:-frequency
63:Leigh light
52:ASV Mark II
1505:Categories
1345:Radar Days
1307:(33): 93.
1143:(33): 68.
1105:Gough 1993
1093:Gough 1993
870:Bowen 1998
858:Bowen 1998
834:Bowen 1998
816:References
709:ASV Mark V
691:Sunderland
661:ASV Mark I
641:magnetrons
481:lend-lease
419:life rafts
164:Royal Navy
118:Avro Anson
1313:1361-4231
1219:1361-4231
1149:1361-4231
821:Citations
566:AN/APS-20
411:schnorkel
404:schnorkel
399:schnorkel
269:H2S radar
258:Metrovick
129:North Sea
71:microwave
24:ASV radar
1395:. HMSO.
1298:"Nimrod"
1282:5 August
1246:6 August
755:AN/APS-4
703:DMS-1000
603:Sea Skua
595:Seaspray
512:Cold War
488:Avengers
361:Mark V.
226:Mark III
98:Seaspray
442:torpedo
170:of the
59:U-boats
1490:
1469:
1420:
1399:
1378:
1352:
1311:
1217:
1179:
1147:
450:flares
434:radome
374:K-band
370:X-band
343:blimps
339:Philco
1368:(PDF)
1301:(PDF)
1207:(PDF)
1137:(PDF)
121:K8758
22:, or
1488:ISBN
1467:ISBN
1418:ISBN
1397:ISBN
1376:ISBN
1350:ISBN
1309:ISSN
1284:2020
1248:2020
1215:ISSN
1177:ISBN
1145:ISSN
464:and
446:RP-3
205:, a
96:and
88:and
1441:doi
1437:132
554:EMI
477:Gee
1507::
1435:.
1374:.
1303:.
1275:,
1255:^
1239:,
1227:^
1209:.
1190:^
1163:^
1139:.
1020:^
978:^
949:^
490:.
468:.
460:,
425:.
406:.
100:.
84:,
1496:.
1475:.
1447:.
1443::
1426:.
1405:.
1384:.
1358:.
1328:.
1315:.
1221:.
1151:.
546:(
Text is available under the Creative Commons Attribution-ShareAlike License. Additional terms may apply.
