Electric Universe

by David Bodanis

  Early on February 26, 1935, the RAF bomber flew past the assembled watchers on a grassy field near the BBC transmitter. (Watson Watt had quietly added a very long dangling strip of metal to the plane to be sure the demonstration worked.) The bomber was tracked to a distance of eight miles. When the test was over, Watson Watt turned to a ministry official, and—in what seems his one recorded moment of brevity—said, “Britain has become an island once more.”

  Dowding didn’t know that the first test was rigged—he was as familiar with the theory of electrons within metals as he was with medieval vowel forms in Serbo-Croat—but he did know that this pudgy, absurdly confident man from Slough was making things happen that no one had made happen before. The RAF had a tight budget, and fighter command had one of the smallest portions, but even so, within a few weeks Dowding had shifted the equivalent of more than one million dollars to Watson Watt. His sole assignment was to find out more about how this “radar” could work to Britain’s advantage, and then show how to build practical radar stations. (The word radar was not in fact coined until 1941, when two American naval officers came up with it as a convenient shorthand for “radio detection and ranging.” In 1935 the less revealing label “Radio Direction Finding” was used, so as not to give too much information to the enemy.)

  But despite the RAF’s support, Watt, like any outsider, needed a stronger protector in the government bureaucracy. As his first memos floated along the corridors of Whitehall, they ended up, luckily, being noticed by the kindly Henry Tizard, a superb administrator. Tizard had test-flown World War I Sopwith Camels, been a lecturer in thermodynamics at Oxford, then the head of Imperial College, and—most usefully for the bureaucratic battles to come—an excellent, scrappy lightweight boxer in his youth.

  There was an especially precarious moment for the project, when Parliamentary twists briefly gave Churchill more influence on the government. Churchill was all for increased defenses against Germany of course, but when it came to science, he depended completely upon the advice of Frederic Lindemann—an angry, status-obsessed ex-academic who could be serenely charming when he wished, and who had the knack of making upper-class individuals feel that they were as wise as the greatest thinkers. Since Churchill’s own scientific education hadn’t quite reached the levels of the early nineteenth century, he had no way of recognizing Lindemann’s incompetence.

  Churchill pushed Lindemann onto Tizard’s committee, and Lindemann immediately explained that he knew for a fact the newfangled radar defenses they were planning were never going to work effectively. It didn’t help that when Lindemann and Tizard had been young researchers, visiting in Berlin in 1908, they’d once agreed to settle a point of honor in the boxing ring. Lindemann was a much larger man and couldn’t bear it that the wiry Tizard had pummeled him; he refused to shake hands afterward. Now in London, Lindemann slowed the constructions that Watson Watt was preparing for several months until, through still more deft bureaucratic footwork, Tizard managed to get Lindemann expelled. He created a dangerous lifelong enemy, but for the time being he had also cleared the way for Watson Watt to proceed.

  By the time of the Munich Crisis of 1938, as the screaming voice of the Führer burst out of German radios, and the signals carrying his words rippled outwards—just as Michael Faraday might have predicted a century earlier—some of those radio signals were soon floating over five huge constructions in the south of England. These were the first of the Chain Home radars: most of the stations had tall metal transmitters, like massive electricity pylons, 350 feet high; the receiver pylons were 250 feet high, and generally built of wood. By the summer of 1939 there were twenty similar stations, concentrated in the southeast of England, but with a few scattered all the way up into Scotland. From each transmitter, long, undulating waves sped out. During the Munich Crisis, the transmitters had sent those waves to follow Prime Minister Chamberlain’s plane to a distance of nearly a hundred miles from the British coast, long after it was out of visual range. Now, with war approaching, the transmitters were increasingly used to identify equally distant British planes, simulating the paths that German fighters and bombers might take.

  The German armed forces had some hints of what was happening, but never got a complete picture, for the various divisions of the German government didn’t talk to one another much. When a Luftwaffe officer named Colonel Wolfgang Martini did finally decide to probe Britain’s defenses in the last peacetime months of 1939 (by trying to listen to any radio signals a radar network would be producing), he most usefully for Britain resolved to be extremely thorough. This meant he had to carry a lot of heavy equipment, and so he used a giant zeppelin airship for the job. (It was the Graf Zeppelin LZ-130, sister ship of the LZ-120 Hindenburg, which had exploded in America just two years before.)

  He couldn’t have chosen a better way of beaming his location to the British. Zeppelins were coated with shiny aluminum varnish, and aluminum is a metal, which meant that the surface of the zeppelin consisted of hundreds of square feet of loosely attached electrons. It formed a perfect target, suspended conveniently high in the air. The first signals from Britain’s radar stations whapped into the zeppelin even before it had completed crossing the English Channel. Electrons in the zeppelin’s aluminum-painted skin immediately began shimmying from side to side, and so began pumping out miniature radio signals just as Wilkins had predicted. While the zeppelin lumberingly hid in clouds during its reconnaissance mission up and down the coast, most of the high masts of the Chain Home stations stayed quiet, giving away no trace of their operation. When the final Luftwaffe intelligence report on British preparedness was delivered, in July 1940, it said nothing about the Chain Home system.

  By the summer of 1940, Germany’s army had conquered most of western Europe and was perched on the edge of the English Channel, just an achingly few miles short of Britain itself. The German navy was assembling a huge invasion fleet, and if that got across the Channel successfully the few armored British units that survived would be heavily outnumbered. (Many British tanks had been destroyed or left behind in France.) Churchill would likely be executed, if he didn’t escape to Canada; German administrators had lengthy lists of prominent Jews, trade unionists, clergy, and other undesirables who would be killed too.

  The Royal Navy would do what it could to block the invasion, but without command of the air, there was little chance it could succeed indefinitely. The RAF was the crucial barrier to Germany’s advance—but it seemed feeble indeed. Spending had been low for Fighter Command, so although there were a good number of topnotch planes available, there weren’t enough trained pilots to keep defensive patrols circling in the air. Hitler had only to get rid of this limited RAF and then he could invade. The air attacks weren’t expected to take more than a month, top German officers calculated. They would begin on August 13, 1940—Adler Tag, or Eagle Day.

  Around 5:30 a.m., the radar operators in the easternmost radar stations in Britain detected a German air formation assembling over Amiens in France. Soon there was another one over Dieppe, then a third north of Cherbourg. The German pilots had every reason to think they were unobserved, for they had no way of detecting the electric and magnetic waves that surged through the metal wings of their planes and produced the signals that—only a fraction of a second later—were accurately received back in England. But when those several hundred planes did reach English airspace for their surprise attack, ten RAF squadrons were waiting for them. As a contemporary observer put it, “Inhospitably, the reception committee turned all these overseas visitors away.”

  It was Watson Watt’s finest hour. Time after time, in the weeks after that, Germany tried to launch a surprise attack, so it could take advantage of its superiority in numbers of planes. Later in August, for example, the German air force feinted with a huge attack on the south of England, while sending an even greater, secretly assembled air armada over from Denmark to attack what it was sure now had to be the undefended northeast. But when those attackers were
still far over the North Sea, the RAF—with deadly pilots from Poland, Norway, and throughout the Commonwealth—swooped upon them.

  It helped that when a few suspicious German intelligence officers did promote attacks on what they thought might be radar stations, the British operators, mostly women, stayed calmly at their oscilloscopes, despite substantial casualties. There was no change in the RAF’s responses. The German High Command was confused enough to conclude that perhaps the curious high masts weren’t a central part of the British defense after all.

  It also helped that the British government encouraged alternate cover stories about the defense scheme. There were leaked press reports that the accurate intercepts, especially at night, were due to the vision-enhancing properties of carrots (which seems to be where the story began that carrots are especially good for your eyes). There was also quick thinking by RAF members. Sergeant Phillip Wareing was shot down while chasing an enemy plane back to France and interrogated shortly after his capture:

  “One German asked me, ‘How is it you’re always there when we come?’ I said, ‘We have powerful binoculars, and watch all the time.’ They didn’t query that at all.”

  Through the rest of August, and well into September, the radar stations continued directing one fresh group of RAF pilots after another straight to the fleets of attacking German planes. Streams of bouncing electromagnetic waves filled the sky, guiding the British planes forward, directed by readings from the calm survivors at the radar stations. Tons of metal wreckage fell from the air. The RAF suffered large losses, but the Luftwaffe’s were larger still. By the end of September, autumn storms in the Channel had begun, and on October 11, Operation Sea Lion—the planned German sea invasion of Britain—was indefinitely postponed.

  Yet the British lead in radar didn’t last. As German night attacks on London and other large cities continued, British radar operators noticed something disturbing about the Luftwaffe’s tactics. The German planes were taking up accurate positions more quickly than they had before, even in total darkness. There was at least one occasion when German dive-bombers based in France flew directly to a British destroyer sixty miles from shore and sank it, even though it had been well out of visual range.

  This was bad news. The Germans were not just catching up with the British in their use of radar, but surpassing them. Britain’s Chain Home radars sent out waves many yards in length. That was good enough for getting a rough fix on airplanes coming in over the English Channel, but such long waves quickly spread wide, wasting much of their energy by uselessly bathing the cows, milk vans, and open fields of southern England. Watson Watt knew that a shorter wave would be easier to aim and more tightly focused. This must be, he and others realized, what Germany was now able to create. The fact that German officers could synchronize their plane movements at night and hit distant warships with great accuracy proved it. But where was Germany hiding the machines that poured out these small electric waves to such deadly effect?

  Radar so far had been the hero—a protector of the nation. Yet once Britain learned how Germany was catching up, it would become a villain.

  8

  Power Unleashed

  HAMBURG, 1943

  The clue that allowed the new German radar sets to be found—and set in motion the events that led to Faraday’s invisible waves being used for immense destruction—seemed innocent enough. It appeared in an eight-page typewritten document that had been sent by an anonymous German citizen to the British naval attaché in Oslo in 1939. The report seemed too outlandish to be true, for it described activities beyond anything Britain had contemplated. There were accounts of a science-fiction-like research establishment on a distant Baltic island where jet-propelled glider-shaped planes were built, along with descriptions of not just one but two radar systems far more advanced than anything Britain had. When the packet was translated and distributed in London, only one individual thought it worth keeping.

  That individual, however, was Reginald V. Jones, a very young-looking twenty-eight-year-old. Although his official training was in astronomy and physics, he had done graduate work at Balliol College, Oxford, where a broad literary background was expected, and it was taught that every received opinion deserved to be questioned. He recognized that Nazi administrators were so suspicious of one another that it was quite possible—as indeed turned out to be true—that several German research teams had been working on radar without the main Luftwaffe officials being aware of it. Now, in 1941, he realized that Germany did have a functional radar system, and—from reading accounts of prisoner conversations and radio intercepts—he also knew that it was code-named “Freya.”

  To someone of his background, this code name carried a clue that would be as revealing of German intentions as if a carrier pigeon with the true information had been sent direct to the Office of Air Intelligence, Whitehall, London SW1. The German High Command was obsessed with Aryan myths. The solution to this great electronic danger of the mid-twentieth century, young Jones realized, would come by going back in time nearly one thousand years.

  Jones strolled from his Whitehall offices, accordingly, one day late in 1941, to Charing Cross Road, the center of London’s book trade. Before the day was out, he had found what he wanted. Freya was an ancient Norse goddess who was described as being usually in the company of Heimdall, another mythological being. Freya had a necklace, and Heimdall’s job was to guard it. To do this, he was given the power to see a hundred miles in all directions—by day or night.

  RAF reconnaissance flights had already found some installations in occupied France that looked as if they could be radar sites, but the devices had seemed too large and old-fashioned to be the cause of the most accurate interceptions now. No one, however, had thought there might be two machines, with different powers, working together. The reference to old Norse mythology—where Heimdall and Freya worked together—made Jones think that this might be what the German command was now building.

  Jones sent a camera-equipped Spitfire fighter back to the first big site that had been found, a few dozen miles from Le Havre, near the town of Bruneval. It was highly polished for top speed, and it roared in just a few hundred feet from the ground, to keep down the amount of time that guards or antiaircraft guns would have to try to fire at it. As soon as the negatives were back in London, Air Ministry photo interpreters got to work. At first they saw only the troop emplacements and barbed-wire barriers and commandeered chateau that would be expected at an ordinary base, but a closer look with magnifying glasses revealed that where a path away from the chateau stopped short, there was indeed yet another radar device, tucked into a clearing no more than a few yards wide.

  This was worse than expected. A radar set small enough to fit in this clearing couldn’t have the huge antennae that Britain’s Chain Home radars required. Instead the photos suggested that the German engineers had produced a radar with waves that wiggled out at five feet or perhaps even less in length. The entire device could fit on the back of a van, with a single yard-wide steerable antenna on top to generate and receive its waves. (Since the Chain Home antennas were the size of very tall electricity pylons, it would have taken hundreds of cubic yards to rotate them, and no engine known could easily do that.)

  No one in Britain knew how Germany had achieved this feat of engineering. If there were more of these sets, and if they were crammed aboard a plane, then German patrols could identify vulnerable American troop transports coming to Britain even in darkness in the middle of the ocean, and send that information to waiting U-boats; individual Luftwaffe fighters could pick out Allied planes in total darkness as well.

  Two volunteers from the French Resistance, Roger Dumont and Charles Chauveau, went in to investigate the base and its small, deadly radar. They found more than a hundred German troops, and at least fifteen machine-gun emplacements. The Royal Navy couldn’t get up there to examine or capture the radar—code-named Würzburg—for although the chateau at Bruneval was on the coast, the sea had cut
cliffs nearly four hundred feet high in the soft chalk. It had to be attacked, and since there were no landing strips, one of the newly formed paratrooper units would have to go in.

  And that was how Charles W. Cox, a diminutive peacetime film projectionist, amateur radio ham, and now most junior sergeant in the Royal Air Force, came to be instructed, one February day early in 1942, to report to the Air Ministry in London. Air Vice-Marshal Victor Tait was waiting for him. Normally Cox tried to spend the day in carpet slippers—he had corns on his feet—and he tended to keep up his trousers with insulating wire rather than a belt. But today, he realized, was special, and he tried to dress properly.

  “You’ve volunteered for a dangerous job, Sergeant Cox,” Tait said.

  “No, sir,” Cox protested.

  “What d’ye mean, ‘No, sir’?” Tait asked.

  “I never volunteered for anything, sir!” Cox said.

  From an unpublished twenty-page account left by Cox’s estate, it’s possible to reconstruct what happened next. Cox was sent to the tightly guarded Ringway training facility near Manchester, where at first he couldn’t understand why he was marching amid dozens of tough paratroopers. After all, he’d never been in an airplane and was afraid of exposed heights. Then in an awful moment he realized that he was in training with them because he was going to be in on their assault. Someone had to supervise the disassembly of the Würzburg radar, if it was going to be captured and brought to England, and on this short notice, his experience as an amateur radio operator meant he was the best the War Office could get.