Technological Intelligence and the Radar War in World War II (RCAF Journal - WINTER 2016 - Volume 5, Issue 1)

By Azriel Lorber

There were few wars or campaigns that were decided by a single device or weapon whose absence likely would have resulted in a different outcome. One outstanding example of this was the English longbow during the Hundred Years’ War. Another was the use of radar in World War II: by British in the Battle of Britain and by the Allies in the Battle of the Atlantic. A German victory in either would have had a decisive effect on the course of World War II, possibly changing its final outcome. The Battle of Britain also shows that creating or even adapting a suitable doctrine for the use of a novel weapon will maximize its benefits and make it prevail, even if said weapon is technically inferior to that of the enemy.

The idea to use reflected radio waves to detect “objects” at night or in fog was first broached by Christian Hülsmeyer, a German engineer, in 1905. He tried to interest Von Tirpitz, then the head of the Kriegsmarine (German navy), but was told that German naval personnel had better ideas. Although demonstrated successfully, Hülsmeyer never managed to garner financial interest for his invention and eventually it was forgotten.

During World War I, the Germans used Zeppelins and aircraft for bombing raids against Britain with some measure of successes. The British tried to discover the approaching attackers by means of the Observer Corps, but they could operate only during daylight. They tried acoustic detectors (which at least worked at night), but their effective range hindered their usefulness and usually the first indication of a raid was the blast of the exploding bombs.

The large strides made by aviation between the wars brought home to the British that the English Channel, which foiled both the Spanish Armada and Napoleon’s troops, would no longer serve as an impassable barrier guarded by the Royal Navy. Aircraft could cross this barrier in a few minutes. This feeling was compounded by former British Prime Minister Stanley Baldwin, who in November 1932, spoke on the subject in Parliament. Among other things, he said: “I think it well also for the man in the street to realize there is no power on earth that can protect him from bombing, whatever people may tell him. The bomber will always get through ... . The only defense is in offense, which means you have got to kill more women and children quicker than the enemy if you want to save yourself.”^[1]

The followers of Douhet^[2] (especially in the United States [US]) who supported the concept of heavy bombardment considered the speech a holy writ and Baldwin its prophet. Here was proof—and from no less a persona than a former British prime minister—that a strong bomber force will prevent war, and if war did come, then heavy bombers would quickly bring the enemy to its knees. Both in the US and England, air power advocates stressed the offensive dominance of the bomber.

The speech shook the British people to the core, but it did have an important consequence. The Royal Air Force (RAF) was leery of the strategic conclusions voiced by Baldwin. Besides, fighter aircraft were much cheaper than bombers. Maybe air defence should be investigated more thoroughly after all?

Several exercises simulating bomber attacks were conducted against the south of England, and it turned out that even when the bombers were detected, by whatever means, and the fighters scrambled, it was almost always too late. Obviously, something better was needed, and this line of thought was probably influenced by the reestablishment of the Luftwaffe in Germany. So towards the end of 1934, the British established the Committee for the Scientific Survey of Air Defence (CSSAD)—the Tizard Committee (named after its chair, Henry Tizard). One of the ideas proposed was to use an energetic radio beam to boil the blood of the attacking airplane’s crew. Preliminary calculations by Professor Robert Watson-Watt had shown immediately that current technologies were not up to the task.

However, one of Watson-Watt’s assistants told him that British Broadcasting Corporation (BBC) broadcasts were often disturbed by aircraft passing near the BBC’s tower. Watson-Watt put two and two together, performed several tests and obtained some money from the RAF (with the help of Air Chief Marshal Sir Hugh Dowding, later Officer Commanding Fighter Command) for further testing. These tests were very successful. By 1937, eighteen Radio Detection and Ranging (radar) stations were constructed along the southern and south-eastern coasts of Britain. Named “Chain-Home,” the system was declared operational in 1938. Their task was to give sufficient warning about the approach of enemy aircraft.

Obviously, the sooner this information reached the fighter squadrons the more time to take-off. But here the British came to a very important conclusion. The intuitive solution to this problem would have been to increase the detection range of the radars, but frequent exercises had shown that the real bottleneck was in the control and communications network in this complex battlefield. The RAF understood that collecting and sifting the information from the various radars and the Observer Corps (which was reactivated) and creating a coherent picture (“air-picture,” in today’s parlance) would improve battle management. Consequently, they created filter rooms at Fighter Command’s headquarters (to sift and organize the incoming information); established sector stations to actually manage the battle; and laid down an extensive communications system, which enabled the flow of information between these bodies and down to the fighter airfields. It was the first modern command and control system.

The construction of the Chain-Home stations could not be hidden, and tourists from all over the world, including Germans, visited various sites, so the Luftwaffe decided to investigate. They took two Zeppelins loaded with all sorts of radio receivers and, in May 1939, sent them to cruise along the British coast. However, except for annoying “noise” in their earphones, the operators heard nothing. This was not because of equipment problems, but because of an erroneous assumption on the part of the Germans.

Germany already had its own radar, and they were more advanced than those of the British. Thus, they assumed that British radar, if indeed it was radar, operated in a range of frequencies similar to their own, namely about 400 to 600 megahertz (MHz), corresponding to wavelengths of 75 to 50 centimetres (cm), which was the peak of electronic performance at the time. What the Germans did not know or suspect (although in a properly run intelligence organization this should have been one of the first things to ascertain) was that the British radar operated at a lower frequency of 200 MHz. Such radars were less efficient in several respects but sufficed for British needs. The rather mundane reason for this was that lower frequencies enabled the use of commercial radio components—readily available and cheaper. The Germans, always striving for perfection in engineering design, could never imagine that anybody would prefer to work in a less than perfect manner.^[3]

German problems were not limited to technology. The navy was involved in radar work from the early 1930s (because of the need to better control long-range gun fire), but told no one about this. In July 1938, Goering, head of German aviation, found out about it by accident. Understandably enraged at what he saw as a Luftwaffe sphere, he approached the navy for an explanation, but its response was that this was a naval weapon and he should invent his own.^[4]

In August 1939, the Zeppelin flights were stopped, with the Germans still not sure if these were operational radars. But then the Germans made another mistake of strategic consequences. Hitler, who wanted to conquer Poland as the first step on the road east, hoped that Britain and France would not honour their pact with Poland and would not go to war against him. Still, it should have been clear to him that if perchance the British and French chose to fight, the air arms (on both sides) would play a critical role. Therefore, if indeed the Chain-Home towers had anything to do with radar, or were part of Britain’s air defence, then the current doctrine of air warfare, partially developed as lessons from the Spanish Civil War, had to be modified, or at least rethought. Since the Germans themselves had radars, this lapse in strategic thought was twice as bad. It was not obvious at the time, but the first technological intelligence battle between the RAF and the Luftwaffe ended in a resounding British victory.

To German surprise, the Allies honored their obligations to Poland, and on 3 September 1939, declared war on Germany. Two days later, the British sent a bomber force to raid the wharves at Wilhelmshafen. German radar detected the bombers at about 130 kilometres, but they had no standing organization to liaise between the radar units, the Luftwaffe command organization, and the fighter bases. The British bombed their targets and turned for home before German fighters even took off. The Germans, who thought in terms of attack, neglected defensive concepts and had not thought of the integration of detection and interception into one system.

This attack, which took place in poor weather, did not achieve much, so the British waited for another opportunity. This came on 18 December, when 22 bombers again approached Wilhelmshafen. The Germans discovered them and scrambled, though barely in time, and shot down 12 of the attackers. Another 3 crashed on landing. Following these raids, the British reached several conclusions concerning bomber operations and equipment. However, because of the slow response of the German fighters, they also concluded that the Germans did not have radar.^[5] Yet what happened on the German side was even more interesting. The details of these battles, and particularly the second one, were analysed in minute detail, mostly to confirm or reject pilots’ claims about shooting down enemy planes. Everybody agreed that the interception succeeded only thanks to radar’s early warning, but this conclusion was not considered important. It was somehow sidetracked and never included in German air-warfare doctrine.

After the fall of France, Hitler decided that he had to conquer Britain to remove a future threat, but an invasion of Britain would be impossible as long as the Royal Navy, supported by the RAF, controlled the English Channel. The required first step was to eliminate the RAF Fighter Command as an effective fighting force. By then the Germans understood that the strange towers on the British coasts were indeed radars, and what’s more, they listened to the conversations between the pilots and their ground controllers.

Commencement of operations against Fighter Command was set for 12 August 1940, and Goering predicted that this arm of the RAF would be destroyed in four days.^[6] It was obvious that he did not know much about the RAF. In this, he was done a disservice by the Luftwaffe’s chief intelligence officer, Major Joseph Schmid.^[7] On 16 July, Schmid submitted a report about the RAF, in which he described it in all parameters as inferior to the Luftwaffe.^[8] A worse blunder was that the report did not mention radar at all. On 7 August, Schmid wrote another report in which radar was discussed but stated that British fighter planes were controlled from the ground and thus tied down to their controlling stations and limited in their mobility. He wrote: “Consequently the assembly of strong fighter forces at determined points and at short notice is not to be expected. A massed German attack on a target area can therefore count on the same conditions of light fighter opposition as in attacks on widely scattered targets.”^[9] Schmid understood that radars detected the approach of enemy aircraft, but he did not understand that radar was only a part of an integrated command and control system, which assigned assets according to need. At that time, the Germans did not have a similar organization. The lessons of the Wilhelmshafen interceptions were forgotten, and the Germans were slow to understand the existence and role of such an organization. Radar, the focal point of this system, served as a “force multiplier” because it enabled the controllers to direct the fighters to the approaching German formations and prevented day-long patrols, saving wear and tear of both aircraft and pilots.

Schmid was hampered by his own inadequacies. He was not a pilot and did not speak any language except German; his previous career was with the ground forces. (His counterpart on the British side was an air commodore, equivalent to a brigadier-general.) Furthermore, in all of his reports, he badly underestimated British aircraft strength and production capabilities.^[10] His lowly rank may point to the rather low esteem the Germans held for intelligence work and to their limited expectations as to the quality of information which could be obtained from it.

Luftwaffe attacks on 12 August focused primarily on Fighter Command’s airfields in order to destroy ground facilities and airplanes on the ground. On the first day, the Germans also attacked four radar stations. Three were lightly damaged, and one was destroyed. The Germans soon discovered that those towers were hard to destroy but did not suspect that the huts scattered around the towers were important, as the radar equipment, operators, and electrical generators were housed in them. In order to save money, the aviation ministry had this critical equipment housed in simple above-ground huts. The same applied to the sector stations. A German change of tactics, for example, switching to carpet bombing, could have wiped out the whole British air-defence system in one morning.^[11] German thoroughness probably assumed that the “real” equipment was underground, under 10 feet [3 metres] of concrete (at least they would have done it that way) and that those huts were dining and storage facilities, not worth the price of the bombs. This highlights the mistake of projecting one’s own thought processes and operating procedures onto the enemy.

The British also used some deception by activating a dummy transmitter at the destroyed station.^[12] It could not receive anything, but the Germans did not know this. Goering’s conclusion was that the effort invested in destroying the radar stations was wasted. At a meeting after the first day’s operations, attended by Schmid as well as Colonel Paul Deichman, chief of staff within Air Fleet II which ran the campaign, Goering said that the attacks against the radar stations did not put them out of action. Schmid added that these radar stations were not important. But Deichman, who should have known better,^[13] said: “Leave the British their radar. It will enable them to find our fighter formations, who will thereupon destroy them.”^[14] Consequently, attacks against the radar stations were stopped. This was an enormous blunder, and it can be said that on that day, Germany lost the Battle of Britain and, by projection, perhaps the war.

The Germans were not alone in not understanding radar. The American military got interested in a radar-based command and control system only after the Battle of Britain. The fact that the British did not talk much on the subject contributed to this lack of interest.^[15] The American failure is emphasized by the fact that the navy’s research department had worked on the subject of radar since 1922, with its first radar development project initiated in 1930.^[16]

The Battle of Britain kept raging through the summer and German losses increased. When a German airplane was shot down, its crew—if it survived—was captured. A downed British pilot, if unharmed, could go back to flying on the same day. After a mission, the Germans still had a long flight home, sometimes in damaged aircraft with wounded crew members. German fighter pilots often ditched in the English Channel for lack of fuel, and although the German air-sea rescue service was most efficient and pulled most of these pilots out, this still was a traumatic experience.^[17]

During August and at the beginning of September, a change in pilots’ reports after returning from missions was evident. Contrary to pre-mission intelligence briefings, which claimed that the RAF was launching its last aircraft, the pilots reported that they did not think that the enemy was seriously hurt. The decisive day was 15 September, with both sides making an all-out effort. Churchill, on a visit to Fighter Command, was told that no reserves were left.

Although German losses were higher than those of the British, the British, too, had serious problems. The pilots were exhausted from the relentless fighting, and the replacements were not adequately trained. Also, because of the incessant bombing, the critical air-defence telephone network was nearing collapse. But then Hitler made another mistake.

A few days earlier, a German bomber made a navigational error at night and bombed London; the RAF retaliated and bombed Berlin. The damage was insignificant, but an enraged Hitler ordered Luftwaffe attacks switched from Fighter Command’s airfields to London. The German leadership had no idea of Fighter Command’s sorry state, and the sloppy management of the Luftwaffe’s intelligence, headed by Schmid, prevented it from getting the real picture.

In the end, the Germans blinked first. Switching the attacks to London gave Fighter Command the breather it needed, as veteran pilots rested, new ones gained experience, and the communications system was repaired. The Chain-Home system enabled Fighter Command to keep its head above water long enough to stop the German onslaught, but the German problems with radar had not ended.

Radar of that period operated in the frequency ranges of 200 to 600 MHz, namely wavelengths of 150 cm to 50 cm. It was understood that radars operating in higher frequencies, of about 3,000 MHz [9.99 cm], were better. They required smaller antennas, enabled better resolution of targets, and generally were more efficient. These frequencies could be achieved, but such devices provided only 40 watts of power, much too low for radar. Furthermore, initial calculations convinced the Germans that at these high frequencies, much of the transmitted energy would be reflected in all directions and not enough would return to the receiver, and receiving this reflected energy is, after all, the essence of radar.^[18] Arguments in Germany about this topic became emotional, leading to the disruption of orderly work to such an extent that in mid-January 1943, an order was issued to stop forthwith all work on centimetric wavelength radars.^[19]

The British knew nothing of this German debate. Three years earlier, at the beginning of 1940, two University of Birmingham scientists developed a simple device, partially based on previous American ideas, which worked at the centimetrric range. This was the cavity magnetron which, during the first tests, produced hundreds of watts of power. After some tweaking, there emerged a practical system producing 12 to 15 kilowatts at a wavelength of 9.5 cm.^[20]

The British knew that due to lack of resources they would not be able to mass produce these systems. At the end of August 1940, a British delegation went to the US to discuss scientific and technological cooperation and to ask the Americans for help in finalizing the development and starting production of some of the advanced technologies they possessed. Churchill personally directed that the most advanced technologies be shown to the Americans without any restraints and without asking for quid pro quo. This delegation was headed by Henry Tizard, of CSSAD fame.^[21] The Americans showed polite interest in the British developments but were “shaken” by the cavity magnetron. They quickly got organized for further research in this field and for production of these radars for the British.^[22]

A centimetric radar was first tested in flight in March 1941, and it was found that it could distinguish ground features such as rivers, towns, and even roads, and do so even through cloud cover. It was quickly understood that this would immensely help night bomber crews who groped their way in the darkness in German skies, especially when flying above the clouds.

The new radar also proved efficient for discovering submarines. Older type radar was already used in this role, but the Germans discovered it in a captured airplane and developed the “Metox” receiver to detect this radar’s broadcasts. Here was a new technology, which the Germans believed was impossible to achieve and were not set to detect when they lucked into finding one. This would enable the sub-hunting aircraft potentially months of success without the submarines being the wiser.

A new debate ensued immediately over who was to get the new radars. Night fighters, flying against German bombers, were the first to receive them, but these quantities were small. The real dispute was between Bomber Command, which wanted better means for bombing its targets, and Coastal Command which was in charge of fighting the submarines. Coastal Command had a convincing argument. Since bombers had a tendency to be shot down in enemy territory, the new technology would quickly be handed to the Germans on a silver platter.

Watson-Watt, considered to be the “father of British radar,” supported Bomber Command’s claims but was astute enough to warn that if such radar fell into German hands it would take them only a month or two to develop some countermeasure. Air Chief Marshal Arthur Harris, in charge of Bomber Command, was not interested in any of this. He wanted to bomb Germany and would not listen to other considerations, even if they affected the conduct of the war as a whole. Churchill, who also passionately hated the Nazis, was convinced by Harris. Towards the end of 1942, Bomber Command started getting the new radars, and at the beginning of 1943, so-equipped aircraft were released to fly over enemy territory. On 2 February 1943, one such bomber was brought down near Rotterdam in Holland. The apparatus was damaged, but the heart of the new radar, machined from a solid piece of copper, survived.

The radar was taken to a laboratory, and the scientists examined the gift that had fallen from heaven and into their laps. They quickly understood what it was and what were the technical capabilities of the novel device. But instead of being happy, they were struck by gloom. Goering expressed the reasons for this in the best way. “I expected the British and Americans to be advanced, but frankly I never thought that they would get so far ahead. I did hope that even if we were behind, we could at least be in the same race.”^[23]

Here “Lady Luck” intervened in a most bizarre fashion: this radar was captured by the Luftwaffe, but for a long time, the Luftwaffe did not bother telling the German navy about this astonishing find; thus, the navy found about it only in September. This failure was summarized by two American navy researchers. “How this six months’ delay occurred is one of the mysteries of the war and a significant factor in the U-boat war (it can perhaps be explained only by a criminal lack of liaison between the German air and naval technical staffs).”^[24]

Finally, several months after Bomber Command, Coastal Command also got its radar. Equipped with an “undetectable” radar, it went after the submarines with a vengeance, and the growing list of submarines lost started causing consternation in the German navy’s high command. Still, even after the navy was apprised of the new radar, it took several months of work to come up with a warning receiver, the “Naxos,” for this wavelength and, because of haste, the Naxos’ production and installation into the submarines were shoddy. Luck again played a role. When a German radar experimentation team went on a submarine patrol, the submarine was sunk and the team captured.^[25]

The range of these radars was fairly short—several kilometres—but the Germans were never able to ascertain what the detection range was. Once the submarines cleared the Bay of Biscay, the British had difficulty following them. However, two other devices came into play. One was by triangulation of the sources of radio transmissions by means of receiving stations on land or at sea. This was called high frequency direction finding (HF/DF) and often the HF/DF triangulations were combined with Enigma (the code name given to a German coding device) decrypts (the information gleaned from this source was code-named Ultra). The Germans eventually suspected that the locations of their submarines were linked to radio transmissions, but in their ocean-spanning operations, they could not stop using radio.^[26] They tried to tighten security by shortening transmission times, changing frequencies, and similar measures, but the Allies needed only approximate positions and the radar did the rest. Ironically, on one occasion, the Germans shot themselves in the foot. German agents in Spain took photographs of British ships in Gibraltar which had the peculiar looking HF/DF antennas on top of the masts, and these photos were to be included in ship recognition books. But an overzealous German security officer painted out the background of the photos, which, together with the tell-tale antennas, might have disclosed their origin.^[27]

The increasing losses convinced the Germans that Allied radars had almost mythical capabilities, which enabled them to detect submarines at very long distances in the vast reaches of the ocean. Thus, the centimetric radar did one more service to the Allied cause: the shock of its discovery and the Germans’ preoccupation with its performance helped screen the Ultra secret.

Both the Battle of Britain and the Battle of the Atlantic were pivotal campaigns in World War II. A defeat in either could have spelled a total defeat or withdrawal from the war for Britain; the possible defeat of the Soviet Union; and an American return to isolationism, at least until a Japanese attack. Not belittling the dedication and sacrifice of the “few,” the outcomes of both of these campaigns and particularly the Battle of Britain were decided by the use of radar.

Germany had an initial lead in radar technology, and the British erred by refusing to accept German possession of it. The initial British blunder with centimetric radar allocations was mitigated by German inefficient handling of technological innovation; in essence, an organizational problem.^[28] However, the British perceived that reaping the benefits of novel technologies (whether homegrown or acquired) requires understanding their battlefield potential and the creation of suitable doctrinal and organizational frameworks for their efficient exploitation and improvements. By neglecting to grasp these imperatives, compounded by poor intelligence work, Germany failed to translate its technological lead to a long-lasting operational superiority.

Truly, as author Robert Buderi emphasizes, radar is “the invention that changed the world.”^[29]

Azriel Lorber served in the Israeli Defence Force in the armoured corps, from which he retired as a major. He studied Aerospace Engineering in the US, obtaining a doctorate from the Virginia Polytechnic Institute. Since retiring, he does consulting work and teaches courses in military technology. His latest book, Ready for Battle: Technological Intelligence on the Battlefield, was recently published in the US.

BBC―British Broadcasting Corporation
cm―centimetre
CSSAD―Committee for the Scientific Survey of Air Defence
HF/DF―high frequency direction finding
MHz―megahertz
RAF―Royal Air Force
US―United States

note[1]. Eugene M. Emme, ed., The Impact of Air Power: National Security and World Politics (Princeton, New Jersey: Van Nostrand Company, 1959), 51–52. (return)

[2]. Giulio Douhet was an Italian officer and thinker who claimed that in a future war the issue could be quickly decided by air power, particularly bombers, without repeating the horrors of World War I’s trench warfare. (return)

[3]. When captured Soviet tanks were first exhibited to Hitler, he commented that they could be no good “because the standard of finish was terrible, and that no one who was doing a decent job would leave his work in that state.” R. V. Jones, The Wizard War: British Scientific Intelligence 1939–1945 (New York: Cowan, McCann & Geoghegan, 1978), 333. We know, of course, that where it mattered, Soviet tanks were well made. It appears that German engineers, in all fields, did not understand where to save effort without compromising performance. (return)

[4]. Louis Brown, A Radar History of World War II: Technical and Military Imperatives (Bristol, United Kingdom: Institute of Physics Publishing), 1999, 78. (return)

[5]. Alan Beyerchen, “From Radio to Radar,” in Military Innovation in the Interwar Period, eds. Williamson Murray and Allan Millett (Cambridge, United Kingdom: Cambridge University Press, 1996), 276. Even in the face of irrefutable evidence, the British held steadfastly to the erroneous notion that they were the sole possessors of radar technology. Luckily for them this mistake did not affect the coming battle. (return)

[6]. Stephen Budiansky, Air Power: The Men, Machines, and Ideas that Revolutionized War, from Kitty Hawk to Iraq (New York: Penguin Books, 2005), 235. (return)

[7]. The literature gives conflicting information about the man’s rank and even the spelling of his name, but there is no doubt of his meteoric advancement. Derek Wood and Derek Dempster, The Narrow Margin: The Battle of Britain & The Rise of Air Power 1930–1940 (New York: Paperback Library, 1969), 90, write that in 1938, when he became chief of Luftwaffe intelligence branch, Schmid was a major. Budiansky, Air Power, 220, writes that Schmid was a colonel, still somewhat low for that position. After a stint in North Africa as an armoured division commander, he was extricated from Tunisia on Goering’s order and made the commander of the German night-fighters arm. In Hitler’s Blitzbomber (Maxwell Air Force Base: Air University Documentary Research Study, 1951), 39, Eugene M. Emme states Schmid’s rank in that position as generalleutnant, which even in time of war was a fast promotion track. (return)

[8]. Derek Wood and Derek Dempster, The Narrow Margin: The Battle of Britain & The Rise of Air Power 1930–1940 (New York: Paperback Library, 1969), 95–99. (return)

[9].Derek Wood and Derek Dempster, The Narrow Margin: The Battle of Britain & The Rise of Air Power 1930–1940 (New York: Paperback Library, 1969), 103. (return)

[10]. Richard Overy, The Battle (New York: Penguin Books, 2000), 126. (return)

[11]. Peter Townsend, Duel of Eagles (New York: Simon and Schuster, 1970), 333. (return)

[12].Peter Townsend, Duel of Eagles (New York: Simon and Schuster, 1970), 313. (return)

[13]. Deichman flew as an observer in World War I and was trained as a pilot in the Soviet Union during the period of cooperation between the Soviets and the Weimar Republic. (return)

[14]. Townsend, Duel of Eagles, 333. Even if we disregard the typical military overconfidence and conceit, Deichman made a basic mistake. He should have known that when fighting on a wide front the attacker has the advantage of choosing the point of attack and being able to amass his forces at the schwerpunkt (centre of gravity) as Clausewitz called it. The defender does not have this privilege and has to spread his forces along the whole front. Radar, and the attendant control system, enabled the British to concentrate their meager forces where the Germans intended to attack and somewhat redress the balance of forces. If the Germans were looking for a sporting event, it was simpler to broadcast to the British the location and time of the next attack, but as a military move, this was contrary to the principles of war, particularly surprise and dispersal of enemy forces. Again, Clausewitzian concepts. (return)

[15]. Thomas G. Mahnken, Uncovering Ways of War: U.S. Intelligence and Foreign Military Innovation, 1918–1941 (Ithaca, New York: Cornell University Press, 2002), 159–60. (return)

[16]. David K. Allison, “New Eye for the Navy: The Origin of Radar at the Naval Research Laboratory,” Naval Research Laboratory Report 8466 (Washington, DC: Naval Research Laboratory, 1981). (return)

[17]. Single-engine fighter planes of the period were notoriously “short legged” and, particularly because air combat, required flight at full throttle. The Messerschmitt Me-109, the German workhorse of that time, had about an hour’s endurance, and on too many occasions these fighters had to leave their charges and turn home and often still had to ditch. Cajus Bekker, The Luftwaffe War Diaries (London: Macdonald & Co, 1971), 236. Adolf Galland, The First and the Last: The Rise and Fall of the German Fighter Forces 1938–1945 (New York: Henry Holt, 1954), 31, also complains about the lack of auxiliary fuel tanks, which he says were already tried in Spain, because this limited the bombers’ penetration distance. Consequently, the whole area of Britain north of London was an (almost) bomb-free haven. (return)

[18]. David Pritchard, The Radar War: Germany's Pioneering Achievement 1904–1945 (Somerset, United Kingdom: Patrick Stephens, 1989), 87. The Germans were essentially right, although for this effect to manifest itself, even shorter wavelengths were required, which were not achievable by that time’s technology. They probably based their calculations on the work of James Maxwell (1831–1879), which was later broadened by Arnold J. W. Sommerfeld (1868–1951). This work was again broadened in the 70s of the last century by Pyotr Ufimtzev and led the way to stealth and the F-117, although Ufimtzev was not aware of that at that time. See Ben R. Rich and Leo Janos, Skunk Works: A Personal Memoir of My Years at Lockheed (New York: Little, Brown & Company, 1994), 19–22. Since the Germans were interested in radar and not in stealth (which at the time smacked of science fiction anyway), they concluded that very high frequency radars were useless. (return)

[19]. David Pritchard, The Radar War: Germany's Pioneering Achievement 1904–1945 (Somerset, United Kingdom: Patrick Stephens, 1989), 88. (return)

[20]. For a full account of the development of this device see Robert Buderi, The Invention that Changed the World (New York: Simon & Schuster, 1997), 82–88. (return)

[21]. The Tizard mission carried with it all the latest British technological advances, such as the jet engine; data on British research into atomic bombs; rockets; gyroscopic gunsights; submarine detection devices; self-sealing fuel tanks; and the cavity magnetron, the heart of the centimetric radar (Buderi, Invention that Changed, 27–28). All of these were freely disclosed to the Americans. (return)

[22]. E. G. Bowen, Radar Days (Bristol, United Kingdom: Adam Hilger, 1987), 150–63; and Buderi, Invention that Changed, 27–28, 37. (return)

[23]. Alfred Price, Aircraft versus Submarine: The Evolution of the Anti-submarine Aircraft, 1912 to 1980 (London: Jane’s Publishing, 1980), 118. (return)

[24]. Philip M. Morse and George E. Kimball, Methods of Operations Research (Washington, DC: Operations Evaluation Group, Office of the Chief of Naval Operations, Navy Department, Operations Evaluation Group Report No. 54, 1946), 96. Having now the whole picture, one can speculate if this was Goering’s revenge for the incident (described above) when in 1938 he was told by the navy to go and invent his own radars. (return)

[25]. Philip M. Morse and George E. Kimball, Methods of Operations Research (Washington, DC: Operations Evaluation Group, Office of the Chief of Naval Operations, Navy Department, Operations Evaluation Group Report No. 54, 1946), 96. (return)

[26]. The coordination of ocean-spanning submarine warfare required large-scale radio traffic, and the German high-command was aware of the danger but considered it a necessary evil. But trusting the Enigma as undecipherable, the “encouragement of communications led to an almost complete relaxation of radio discipline,” and so the “U-boat command became ‘the most gabby military organization in all the history of war.’” David Kahn, “The Code Breakers” (New York: Scribner, 1996), 503; and Alfred Price, Aircraft versus Submarine: The Evolution of the Anti-submarine Aircraft, 1912 to 1980 (London: Jane’s Publishing, 1980), 125. (return)

[27]. Alfred Price, Aircraft versus Submarine: The Evolution of the Anti-submarine Aircraft, 1912 to 1980 (London: Jane’s Publishing, 1980), 143–144. (return)

[28]. In a similar context, although referring to another topic, it is prudent to remember the following observation: “To rely on one’s enemy’s bungling to prevail on the field of battle was at best a tenuous strategy not conductive to long life and happiness.” Wolfgang W. E. Samuel, American Raiders: The Race to Capture the Luftwaffe’s Secrets (Jackson, MS: University Press of Mississippi, 2004), 426. (return)

[29]. Robert Buderi, The Invention that Change the World: How a Small Group of Radar Pioneers Won the Second World War and Launched a Technical Revolution (New York: Touchstone, 1997). (return)