Figure 1.--. |
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W While radid gave the German Panzers a critical advantage in the Battle of France, it would be radar that would turn that advatage to the British in the Battle of Britain. The Germans began the War with many serious limittions (force size, industrial capacity, raw materials, and agricultural productivity), Hitler believed that surperior scientific and indistrial capabilities as well as fighting spirit would in the war. It was not an optimistic sign for the Germans that they would be defeated by British technology when held most of the advatages. Radar was not unknown to the Germans. With their focus on offensive operations and belief that they had superior aurcraft, the Luftwaffe did not give much attention to radar development, although the Kriegsmarine did. Nor did knowcking out the Chain Home Network feature prominantly in the Luftwaffe assault on Britain. They were focused on destroying the Royal Air Force on the ground which they had largely done in their previous offensives. They assumed that they could do the same when they launched Eagle Day. The Lufwaffe was shocked not only when radar warmings saved the RAF, but with the quality of the British fighters and skill of the larely inexperienced British pilots (July 1940). Even while the Battle of Britain was being fought out, Britain was transferring radar and other electronics technology to the United States. A new radar set on Oahu spotted incoming Japanese carrier aircraft, but the operators did not yet have confidence in the equipment (December 1941). The U.S. Navy was rapidly equipping their ships with radar and this would give the Pacific Fleet a needed critical edge in the biter-fought engagemebnts ariund Solomons when the Imperial Fleet still had superior forces. Radar played an especially important role in the American Pacific submarine campaign. The Kriegsmarine initally gave more attention to radar than the Luftwaffe. Radar controlled guns wert a factor in Bismarck's sinking of HMS Hood. Unlike the British, the Germans did not begin transferring radar technology to their Japanese ally until late in the War. SONAR is often thought of in connection with the Battle of the Atlantic, but radar may have played a more important role. The British worked out early in the War that aircraft were the key to defeating the U-boats. The Atantic is, however, a big place and to kill a U-boat you needed to find them. Early radar sets were too big for aircraft. The British had the answer--the Cavity Magnetron. This not only permitted radar sets to be put on small craft, but the short wave lengths enabled much greater percission in findung the U-boats. But the British did not have the industrial capicty to build them. This was taken up by the Raytheon Corporation in America with technical support of the Massachusettes Institute of Technology. This resulted in both mass production and minuarization. Allied patrol craft were equipped with radar which could pick up on even a p eriscope. By late 1943, U-boat duty was one of the most perilous assignments in World War II. As the ballance in the air war changed, it was the Germans who used radar to detect incoming bombers. The Kammhuber Line prioved extremely effective. German radar, however, could only detect the Allied bombers, it would not counterbalance the industrial capacity of the United States and Britain and the waves of bombers, eventually accompanied by fighter escorts, hurled at the Reich.
Elecrinic warfare began with World War II. Wireless communicatioin, espevcao=illy portable radios were very limited in World War I. Naval vessels had radios and here there was some limited electroniic warfare. The Battle of Jutland occurred because the British intercepted German fleet commuications, but on land there was virtually no electronic warfare. And aircraft used in the War were not powerful enough to carry the bulky radio sets of the day. While radio gave the German Panzers a critical advantage in the Battle of France, it would be radar that would turn that advatage to the British in the Battle of Britain. From an early point it was clear that radar and sonar would be key to the Nattle of the Atlantic, although the Royal Navy Admiralty was shocked to learn that existing sonar was ineffictive against new German U-bioat tactics.
Radar was invented independentky by British and German scientusts. Perhaps because of science fiction noveks and movies, the British Air Ministry Air Ministry became concened about the oossibility of powerful death rays (1930s). There were rumors that the Germans were working on such secret technology. The Ministry offered a £1,000 reward, a non-inconsequential sum at the time, for anyone who could show that such a weapon was fesible, defined as killing a sheep from 100 yards. Robert Watson-Watt and Arnold Wilkins took up the challenge. They determined that such a ray was not feasible, but they accidentally noticed that aircraft flying near BBC radio towers interupted signals. They began to winder if radio signals could detect aircraft, giving birth to Radio Direction Finding (RDF) which eventually became better kniown as RADAR. The Ministry picked up on this discovery, finded reserach, and used it to build the Chain Home Network. The Germans were not building a death ray, basically everything else, but not a death ray. They were, however, working with using radio waves for stection, at forst the detection of ships. A new compamy was established to woirk on this -- Gesellschaft für Elektroakustische und Mechanische Apparate (GEMA). This attracted the interest of Genany's most important electronics comnpanies -- Telefunken. All of this was commercial decusions by private companies, not military contracts. Neither Hitler or Luftwaffe Chief Herman Göring showed the sligtest interest, if they even knew about it. Radar at first was seen as a defensive technology. Thus the British were interested and the Germans were not. This would be in sharp contrast to Winston Churchill who was greatly interested and would call the resulting electronics struggle--the Wizzard War. The pre-War developments meant that both Britain and Germany had the basic technology. The Germans were actually somewhat more advanced, but it was the Briutush whi first put it to practical use. Work was also occurring in the United States, the Soviet Union, Japan, the Netherlands, France, and Italy, but was not very advanced. When Britain turned its secret technology oiver ti Amnerica (1940), the huge American electronics industry soon made the United States a major olayer in RADAR. Similar exchanges within the Axis did not occur until late in the War.
The Germans began World War II with many serious limitations (force size, industrial capacity, raw materials, and agricultural productivity), Hitler believed that surperior scientific and industrial capabilities as well as fighting spirit would overcome these limitatiions and win the war. The Germans had attempted to assess British electronic systems before the War with efforts like flying Zephlins allng the coast but determined inaccurately that the British had no effective rader detected system. The Chain Hime toiwers of course could not be hidden, but the Geramn did noit believe thaey were oart of an effective system. The Germans captured a British mobile radar at Dunkirk (June 1940). They were not impressed. Their assessment was that British radar technology was not highly advanced The Luftwaffe conclusion was that radar was actually adversely affecting the RAF, creating problems like tieing fighter squadrons to a rigid system of ground control -- totally opposite to the free ranging hunter philosophy of the Luftwaffe fighter pilots. The victory of the RAF came as a shock to the Germans who nbased vtheir war plan on defeating suoperior numners with advanced technology. It should have been a warning signal for the Germans that they had been defeated by British technology when they held most of the advatages and superior bnumbers. It was a warning that Hitler and his war planners simply ignored.
Radar was not unknown to the Germans. Both British and German scientists worked on radar before the War. Development of the science was advanced in both countries. In fact the Germans probably had the lead. The difference was the the British developed an effective system using radar. Not only did the Geramns not do this, but they failed to understand the potential of such a system. With the German focus on offensive operations and belief that they had superior aircraft, the Luftwaffe did not give much attention to deploying radar systems, although the Kriegsmarine did. American work on radar was far behind that of the British and Germans. Thanks to the Tizard Mission, the Americans moved rapidly to develop radar. There was a radar station on Oahu which detected the Japanese carrier strike aircraft (December 1941), but no system was in place to give needed warmings like the Britidh had with their Chain Home System more than a year earlier. There was no similar sharing of military technology within the Axis.
Nor did knocking out the Chain Home Network (CHN) feature prominantly in the Luftwaffe assault on Britain. They were focused on destroying the Royal Air Force on the ground which they had largely done in their previous offensives. They assumed that they could do the same when they launched Eagle Day. The Lufwaffe was shocked by the quality of the British fighters and skill of the larely inexperienced British pilots (July 1940). Luftwaffe commanders failed to appreciate the cutting-edge British air defence system. Air Chief Marshal Hugh Dowding had played a major role in bbuilding a coordinated system. No one had conceived of such a systen before, let alone actually building one. The CHN was not only a force multiplier but, turned the outbumbered defender into the attacker. It was magnificely utlilized by 11 Group commander Keith Park. He fulkly understood the CHN and the how to use this important tool placed in Fighter Command's hands. Less enlightened commanders, such as 12 Group commander Leigh-Mallory, didn't fully apprecaiate the CHS and the opportunities it provided. Leigh-Mallory was determined to fight in Big Wings -- large aerial engagemengts like orld War I. The 12 Group Big Wings proved ineffective, largely because they took so long to assemble. One source charges that they and gave the advantage back to the Luftwaffe and were only useful in defending London once the morale of Luftwaffe bombercrews was broken. The sight of a Big Wing coming at bombers who began running for home broke the spirit of the Luftwaffe.
The vulnerability of World War bombers to fighter defenses mean that bombers had to limit raids primarily to nightime. This meant that both Britain and Germany had to develop night fighters and these countries,especially the Germans made the greatest use of night fighters, primnarilt becuse of the massive RAF night attacks on Germzan cities. The Germans after the failure of the daytime Battle of Britain attacks, turned to night raid for several months, but with Operation Barrbarossa the German focus was on the east and then proimarily on protecting German cities, from the RAF night raids and American daylight raids. There were some purpose-built night fighter, but most were heavy fighters or light bombers adapted for the mission, employing some sort of detection capability in low visibility-=-primarily radar. World War II era night fighters also included instrument landing systems for landing at night. Turning on runway lights made an air base an easy target for enemy bombers. The major high performance fidhers (Spitfire, Mustangs, Me-109s, and FW-190s) were not well suited for fightfifghting. Speed and maanuerability were not all that important at night. You needed a larger, iften a two-enginee plane, that could carry the addutionsl loaad the of dection equipmernt. The Me-110, for ecample, was a faoilure as a daylight fighter, bur proved to be an excellent night fighter.
The Kriegsmarine initally gave more attention to radar than the Luftwaffe. Radar controlled guns were a factor in Bismarck's sinking of HMS Hood. Unlike the British, the Germans did not begin transferring radar technology to their Japanese ally until late in the War. As Allied advances in radar began to take its toll on German U-boats, the Germans intriduced the Metox radar detector to warn them that they were being detected by radar. The Germans developoed radar basically on a par with the British, if not in adance of the British. It was radar that gave the Germans the edge in the Denmrk Straits leading to the sinking of HMS Hood, but this mean ground and shio radars. Where the British led was in the development of the cavity magnetron, the most unghearlded secret weapon of World War II. This led to centrimetric radar which could be putg on boats (meaning a small ship) and planes. This would be a major factor in the Battle if the Arlantic. The Allies put advanced radars on escort craft and planes, giving them the ability to deteect U-boats at considerable distance. The Germans began putting radars, but their radars had limited ranges. The Germans received a nasty surprise when they found a cavity magnetron on a British bomber shot down near Rotterdam (February 1943). The Germans were unable to use what they found to produce and deply effective radars, it was to late in the War. Both the U-boat fleet and the Luftwaffe was largely destroyed (May 1943-Msarch 1944). The decisive battle safainst the U-boats were fought out in the Atlantic only 1-3 months after the Germans found the British cavity magnetron.
SONAR is often thought of in connection with the Battle of the Atlantic, but radar may have played a more important role. About the same time the British began building the Chain Home Network, the RAF began doing tests on aerial radra detection (1937). With the technology available at the time, they were unsuccsessful. But they deternmuned they could find ships, including U-boats. A U-boat of course could submerge, but only for short periods. They spent most of the time on the surface. Air-to-Surface Vessel (ASV) radar was easier to develop than Air-to-Air radar. The first ASV Mark I system used long (1.5 meter) wavelength (1940). The British worked out early in the War that aircraft were the key to defeating the U-boats. The Atantic is, however, a big place and to kill a U-boat you needed to find them. Early radar sets were too big for most aircraft. The British had the answer--the Cabity Magnetron. This made it possible to build small setrs thay used sgort wave lenths providing for grrat preciussion. But the British did not have the industrial capicty to build them. This was taken up by the Raytheon Corporation in America with technical support of the Massachusettes Institute of Technology. This resulted in both mass production and minuarization. The German cuntered with a radar dector--Metox. This was made by a French company and proved effective. It aleted a U-boat that a radar set was honing in on them, giving them time to dive. A major problem for Admiral Dönitz was that when a U-boat was sunk, he had no way of knowing what was responsible. Ultra and other inovations were helping the British and Canadians sink U-boats on large numbers (May 1943). And a captured British officer falsely claimed that Metox was emitting signals that alerted the Allies. Adm. Döniutz ordered that Metox be renoved from U-boats (August 1943). This meant that ASV, now the Mark II version was back in business, but the Allies were develped inmcreasiungly sophisticated radars. H2S powrered by the cavity magnitron created the AVS Mark 3 which using shiort wavbe lkengths could detect even a periscope. The Germans developed the Naxos radar detecter, but by this time the U-bpats had already been defeated. The Germans developoed radar absirbiubg coatings, bug again it was too late in the War and the coatingsd degraded rapidly at sea. Allied patrol craft were eventually equipped with radar which could pick up on even a periscope. By late 1943, U-boat duty was one of the most perilous assignments in World War II.
The Battle of the Beams was the electonic conpnent of the World War II strategic bombing campaign. It was waged by the Germans and British. Daylight bombers could use geographic features to locate their targets. The Battle of the Beams began when the Luftwaffe daylight bombing campaign was decisevely defeated by the RAF fighters, climaxing in a furious fight over London (September 15, 1940). The Luftwaffe continued to bomb, but at night at a time that the RAF did not have significant night fighter capability. This created a problem for the Germans, how to find British cities at night, but it was a problem the Germans, unlike the British had already worked out. The Germans developed increasingly accurate electronic systems of radio navigation. The British scientific intelligence led by R.V. Jones,
Assistant Director of Intelligence (Science) at the Air Ministry, responded with a variety of their own increasingly effective electronic counter measures, involving jamming and distortion of the radio waves which significantly dusrupted the Geraman bombing campaign. The German bombing offensive, however, only ended with only a few excepotions when the Luftwaffe shifted East (May 1941), in preparation for the Barbarossa offensive on the Soviet Union. The Whermacht was allready largely in place, but the Lugtwaffe moves only weeks before the actual invasion. Navigation was a problen the Bomber Command had encountered when they concluded from an early point that they coiuld not operate over the Reich in daylight. But they did noy developed electrionic navigational systems until much later than the Germans (1941). And of course once they did, it was the German that were put in the position having to develop countrmeasures. Unlike the Germans, the British steadily expanded the air war, especially with the arrival of the Avro Lancaster (February 1942). When the Americans entered the War it was deciced at the Casablanca Conferencce (January 1943) to begin the around-the-clock bombing of Germany. The British would continue to bomb at night and the Americans would bomb during the Day.
The British closely followed German radar developoments. Of course they coukd be easily located because of their trnasmissions. There were also repoorts from the French Resistance. This included noth Freya (2.4 m) and Würzburg (50 cm) systems. The low-UHF band Würzburg radars were the primary ground-based gun laying radar for the Wehrmacht's Luftwaffe and Heer during World War II. The RAF also dispatched electronic recoinisnave aircraft wuth Y-band receivers and found a Würzburg station on the French coast. This led to Operation Viking (February 1942). Vri=itishg cinamandos managed to get some of the eqyuipmemt, photigrapoh the rest, and capture onr of the German technicians. .
As the Lufwaffe move east to prepare for Barbarossa (1941), the RAF launched the Circus campaign. Leigh-Mallory played an important part in the planning. This was bomber effort with thebombers heavily escorted by fighters. This of course limited the range of the strikes. The idea was to bring the German fighters into combat. The RAF were commonly about 20-30 bombers escorted by up to 16 squadrons of escort fighters. Such bomber formations of this size could not be ignored by the German Luftwaffe. The fighters had to come up. The Luftwaffe defend well against the Circus attacks. Many historians believed that the air assaults should have been deployed in North Africa and Asia. The Luftwaffe was, however, slow to build up home defence with a major radar syste, The Luftwaffe was still committed to peripheral defence strategy advocated by . The peripheral strategy of the Luftwaffe, advocated by Chief of the Luftwaffe General Staff, Hans Jeschonnek. This was to deploy the Reich's fighter defences at the edges of NAZI occupied territory leaving little protecting German cities. [Caldwell and Muller, p. 46.] Jeschonnek began to lose favor after the Allied destruction of Hamburgh. He commoted suiside after ordering SS batteries to open up on Lufwaffe fighters over Berlin. As the ballance in the air war shifted, it was the Germans who used radar to detect incoming bombers and direct Luftwaffe fighter defenses--essentially the German Chain Home Nework. The Kammhuber Line proved extremely effective. RAF Bomber Command was restricted night operations because of the Luftwaffe fighter defences, and the USAF 8th Airforce which suffered terribly in its first year of daylight operations. German radar, however, could only detect the Allied bombers and direct the German fighters to intercept them. Kammhuber had no way of of making up for the massive industrial capacity of the United States and Britain. And waves of bombers hurled at the Reich. And by 1944 the bpmbers were escorted by long-range fighters more capable than the defemding German fighters.
Chaff was a British countermeasure to defeat radar, originally called Window. The Germans were working on a similar application, called Düppel, a name based on the Berlin suburb where it was first developed. It was, however, of much more use to the British who by 1942 were involved in expanding the strategic bombing campaign. The Luftwaffe was by this time declining as an force capable of offensive operations, especially bombing opesations. It was increasingly having to concentrate its declinging force toward defending German cities. Chaff was the the use of aircraft to spread a 'cloud' of small, thin pieces of aluminium, metallized glass fibre or plastic, which incapscitate radar defenses. It appeared as a cluster of amprphoud targets on radar screens or sucessfully swamped radar screens with a large number of multiple returns. Chaff was developed over a year before it was actuallky used. Thus was because the British feared the Germans woukd use iut in them. (Apparently the Germans whi had also deveoped a version, also delayed it for the same reason.) Chaff was especually notable in two major SAllied operations. First was Operation Gomorrah, the devestaing Allied air attack on Hammburg (July-August 1943). The other was its use on D-Day to confuse German defenses as to the Allied primary target (June 1944). The use of Chaff is well documented ikn the historical record. Less wll known is who invented it. The inventor was an unhearelded Britisdh woman named Joan Curran. She was Joan Strothers who was raised in Swansea in Wales. She entered the University of Cambridge's Newnham College (1934), studying physics on a full scholarship and enjoyed rowing in her spare time. Upon finishing her degree requirements in 1938, she went to the University's preeminent Cavendish Laboratory to begin a doctorate in physics. She was never awarded that degree as women were not normally granted degrees. But after Hitler and Stalin launched World War II, she worked at the Telecommunications Research Establishment (TRE) in Exeter. [Jones]
Another use of radar was on the V-1 pilotless ram jet bombs which the Germans began firing on London after D-Day (jine 1944). The British rushed anti-aircraft guns from London to the coast. And radar directed guns using the new proximity fuses proved very effective in shooting down the V-1s. A new highly accurate American radar also proved very effective. This and RAF fighters succeded in shooting down some 90 percent of the V-1s fired at Britain, primarily London.
Even while the Battle of Britain was being fought out, Britain was transferring radar and other electronics technology to the United States. Part of the Tizard Mision (August-September 1940). Technology was one thing, but not of great importance if not backed up by a system to rapidly assess the warnings and vector fighter aircraft to meet the threat. A new radar set on Oahu spotted incoming Japanese carrier aircraft, but the operators did not yet have confidence in the equipment (December 1941). And there was no system in place to scrable aircraft to meet the threat. The U.S. Navy was beginning to equipp their ships with radar. Unfortunatly not raidly enough to give the Pacific Fleet a needed critical edge in the biter-fought engagements around Solomons when the Imperial Fleet still had superior forces and impressive night-fighting capability. Not only were few ships equipped with radar sets, but the commanders involved had no idea how to use what they had. The result was the disaster off Savo Island (August 8-9, 1942) with four heavy cruisers lost and the 1st Marine Division abandoned on Guadalcal. This only began to change when the USS Washington in a naval battle the Japanese were winning, with radar directed gunnery blew the Kongo-class battleship Kirishima out of the water in the Naval Battle of Guadalcanal (November 15). Kirishima was an older abttleship, but had undergone modernixzation and reconstruction and was a fast battlship that could keep up with thev carriers. Radar played an especially important role in the American Pacific submarine campaign. The Japanese began developing radar with some belated help from the Germans, their Axis ally. The Japanese focus before the War was on night fighting, but with optical detection. As the Pacific War developed they began to develop radar. If they had had radar at Midway (June 1942), the battle would have developed very differently. Even on their critically impoerant carriers there was no radar. They did begin to develop and deploy radar, but these systems were not only fairly primitive, but they did not have the industrial capacity to produce radar sets in the numbers needed for the naval and air war with the Americans.
Caldwell, Donald and Richard Muller. The Luftwaffe Over Germany: Defense of the Reich (Greenhill Books: 2007).
Jones, R.V. Most Secret War (1978), 556 p.s
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