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The Invention That Changed the World

 In 1940, a team of British scientists arrived in Washington bearing Britain's most closely guarded technological secrets - including the cavity magnetron, a revolutionary new source of microwave energy. Its arrival triggered the most dramatic mobilization of science in history, as America's top scientists enlisted to convert the invention into a potent military weapon. Microwave radars eventually helped destroy Japanese warships and Nazi buzz bombs, and enabled Allied bombers to "see" through cloud cover. After the war, the work of the radar veterans continues to affect our lives - controlling air traffic, forecasting the weather and providing physicians with powerful diagnostic tools. With anecdotes and revelations, this work explores the work of the scientists who created a winning weapon and changed the world forever.

 THE INVENTION THAT CHANGED THE WORLD  

Vannevar Bush was president of Carnegie Institution in Washington DC. Bush created National Defense Research Committee (NDRC), established in 1938, in order to promote cooperation of civilian scientists with the military (page 34). He provided funding for the Radiation Laboratory (Rad Lab) at M.I.T. (page 50) and he created the Office of Scientific Research and Development, a branch of the U.S. government (page 115). Most importantly, he convinced the stubborn Ernest J. King (Chief of Naval Operations and Commander in Chief of the U.S. fleet) to give up his out-moded and wrong-headed idea that anti-submarine airplanes should only be used for defensive purposes, and that instead the U.S. should adopt an aggressive search-and-destroy effort in using U.S. airplanes and radar to hunt down and destroy German U-boats (pages 158-161).

ALFRED LOOMIS. Loomis was a Harvard law school graduate with Wall Street experience in financing public utilities. He was also interested in gadgets, and setup his own radar lab in Tuxedo Park, New York. He decided to use NDRC money to set up a radar lab at M.I.T., rather than set it up at Carnegie or at Bell Labs (page 45). This M.I.T. lab was called, "Radiation Laboratory," and was founded in Nov. 1940. Eddie Bowen introduced the cavity magnetron transmitter to the Rad Lab. Rad Lab workers also included Luis Alvarez, Ernest Pollard, I.I. Rabi, Lee DuBridge, Edwin McMillin, and Jim Lawson. Their goal was to combine the transmitting aerial and receiving aerial into one aerial (page 101). The Rad Lab focused on air-to-air, air-to-ship, and air-to-sub detection. I.I. Rabi's goal was to reduce the wavelength from 10 centimeters down to 3 centimeters. Loomis provided the innovation of conical scanning (page 109).

RECONCILING BRITISH AND U.S. TECHNOLOGY. When first compared, British radar worked better than the U.S. radar designed at M.I.T. However, when the British receiver was used with a U.S. radar unit, and when the U.S. vacuum tube was replaced with crystals (the U.S. Rad Lab workers had initially rejected crystals, but they did not realize at this earlier time that their crystals had been "burned out"), the result was a radar device suitable for mass production (the year 1941) (pages 117-118).

ROBERT WATSON WATT. Watson Watt was an engineer from Scotland, and expert on radio static and ionosphere (page 55). Watson Watt proposed radar as follows: "at a wavelength of 50 meters a transmitter sending 15 amperes through an aerial should produce a detectable echo from planes 10 miles distant and flying at 20,000 feet." (page 56). Although it was widely known in the 1920s and 1930s that planes and ships interfered with radio waves, Watson Watt added the component of pulses. Pulses is one of the things that distinguishes radar from ordinary radio waves. While pulses had earlier been used for radar, Watson Watt was the first to propose that it be used for military defense.

HERMAN GORING. Goring started the Battle of Britain in July 10, 1940, with 2400 German airplanes. However, during the previous two years, the Germans had paid little attention to the chain of radar towers erected along the English coastline, and because of this oversight, the British were able to use radar to fend off the German air invasion, using Hurricanes, and Spitfires (pages 90-97).

J. RANDALL and H. BOOT at TRE. The cavity magnetron, which provided a better way to generate microwaves, was invented by British men J. Randall and H.Boot at Telecommunications Research Establishment (TRE) in February 1940 (pages 82-83). Another goal of Randall and Boot was to use shorter wavelengths in radar, and this was solved by using the klystron (klystron was invented by Varian brothers at Stanford University).

EDDIE BOWEN. Eddie Bowen worked under Watson Watt while earning his Ph.D., then assigned to a secret radar laboratory in England at Orfordness, and worked on transmitter while others in the same lab worked on receiver and cathode ray (page 65), where they solved problems relating to pulse (they compressed it) and determining the height of invading airplanes (they used perpendicular antennas), and making radar system small enough to fit into airplanes (page 67). Based on these results, the British government built a chain of radar towers along the coast in 1935. In 1936, Eddie Bowen and Watson Watt moved the lab to Bawdsey Research Station. Eddie Bowen's first demonstration of airborn radar took place in Aug. 1937 (page 71), ordered radar to be installed in British airplanes (Blenheim nightfighters). We are told that, at this point in time, Germany had annexed Austria and Czechoslovakia, and had made a non-aggression pact with USSR (soon to be broken by Germany). In Sept, 1939, Hitler invaded Poland in he invaded USSR in June 1941 (page 119). The Bawdsey lab was also where engineers figured out how to coordinate the signals coming from a chain of radar towers into accurate information (filtering system) (page 90).

KARL DONITZ. Karl Donitz commanded German submarines (U-boats) which, by spring 1941, was sinking 100 per month. This period was called Die gluckliche Zeit (Happy Time). The British used ship-to-sub radar and air-to-sub radar to hunt for U-boats (page 121) and also to sink the Bismark (May 27, 1941). Denis Robinson (British) an electrical engineer was responsible for use of crystals in British receivers. Robinson collaborated with DuBridge and others at the Rad Lab at M.I.T. in designing air-to-sub radar (pages 119-125). In early 1942, Donitz started Paukenschlag (which means drum beat) which ushered in a second Happy Time, where German U-boats patrolled the east coast of the United States, singing 35 ships in three weeks, and 216 shps in three months (pages139-142). One reason Donitz was successful was that U.S. military brass (Ernst J. King) distrusted technology, was overly conservative, and also suffered from a character defect (he was overly competitive with top brass from other branches of the U.S. military) (pages 158-161). Donitz continued to sink ships in the Gulf of Mexico and Carribbean (page 151). At this time, the U.S. still did not have any program for systematically searching for and destroying U-boats.

A big advance against U-boats came from the use of the Leigh Light on British airplanes, which supplemented use of radar and was used at close range (page 154). Donitz started using devices (Metox devices) to detect British radar, within two months of initiation of the Leigh Light, allowing U-boats to escape airplanes. At this point, early 1943, it appeared that the Germans might win WWII. Eventually, Vannavar Bush, with the use of delicate diplomatic efforts, was able to convince stubborn Ernest J. King to use radar for aggressive hunt-and-destroy missions against U-boats. Thus, the combination of Vannavar Bush's policy of search-and-destroy missions using radar-equipped airplanes, Leigh Lights, and the use of phony noisemakers towed from Allied ships to trick German acoustic torpedoes, the tide was turned against Karl Donitz, and his packs of U-boats were defeated