Microwave Legends 2007

Aug. 14, 2007
Through their insightful creativity and research, these five historical figures have shaped and in many ways spawned the microwave industry.

?In recognition of last August’s 45th anniversary of Microwaves & RF, the magazine’s editors came out with a list of the industry’s top 45 “Microwave Legends.” That list comprised the people, places, and products or technologies that had made the microwave industry what it is today. Although the Microwave Legends included many of history’s major players, such as Marconi, it also was peppered with some of today’s biggest trailblazers. With 45 entrants, however, it was not possible to capture all of the microwave industry’s legends. As a result, the editors promised to add five legends to the list every year. This year’s entrants, who are found below, were chosen as a result of both research and reader suggestions. The editors of Microwaves & RF are happy to present the following five entrants into the Microwave Legends:

Frank Dawson Bliley—In 1919, Bliley received his first amateur radio license. He went on the air with a spark coil, which was then a 0.5-kW spark transmitter. Two years later, he bought an Audiotron tube and World War I-surplus 50-W transmitter and opened up his radio station on the 200-m band. In 1923—before the amateur frequencies were laid out in “bands”—Bliley (with an experimental license) cooperated with the Naval Research Lab, NKF, and W1XAM, to explore the use of high-frequency energy for various applications. Their goal was to help analyze the propagation properties at various times of the day to frequencies of 30 million cycles per second (Mc or MHz). In 1925, Bliley attempted transcontinental contact with Frank Jones, W6AJF, on 56 Mc but without success. In 1930, he started making crystals as part of his hobby. This “hobby” quickly grew into the Bliley Piezo-Electric Co. in Carlisle, PA. The company was one of the first commercial crystal-oscillator manufacturers. It also was a supplier to armed forces in WWII. Bliley was known for greatly improving performance through an acid-etch technique, which etched away the final layers of quartz when forming the resonators for crystal oscillators.

Jagadis Chunder Bose—Bose, who was born in 1858 in Mymensingh, India, created the world’s first wireless communication link by using millimeter waves for the remote control of a gun. In doing so, he induced electric sparks in a cavity resonator system. In 1895—two years before Marconi’s demonstration—Bose transmitted signals through three intervening walls to a room 75 feet away at Calcutta’s town hall. In 1898, Bose demonstrated his wireless-communication equipment, which was based on the Branly Lodge coherer detector (then dubbed the “Iron mercury iron coherer with a telephone detector”). Meanwhile, Marconi began using a detector in his receiving antenna, which he called a “coherer.” This instrument was communicated to him by Luigi Solari, who essentially modified Bose’s u-shaped tube into a straight tube. Marconi later admitted that he had actually used an “iron-mercury-iron-coherer with a telephone detector.” Among other achievements, Bose is credited with devising the horn antenna and modeling a solid-state detector using Galena. In 1917, Bose founded the Bose Institute.

Heinrich Rudolph Hertz—Hertz confirmed James Clerk Maxwell’s theories about the existence of electromagnetic (EM) radiation. In 1886, this German physicist caused a spark discharge between a spark gap’s poles, which were oscillating at a frequency determined by the values of the capacitor and the induction coil. For the radio-wave transmitter, Hertz used a high-voltage induction coil, condenser, and spark gap. To detect radiation in order to prove that it was being emitted, Hertz used 1-mm-thick copper wire. He bent that wire into a circle and put a small brass sphere on one end. The other end of the wire was pointed. With the screw mechanism that Hertz added, that point could be moved very close to the sphere in a controlled fashion. If there were an oscillating charge in the receiver, sparks would appear across the gap between the point and the sphere. Hertz later established that light is a form of electromagnetic radiation that obeys Maxwell’s equations. The unit of frequency—cycles per second—is named the “hertz” in his honor.

George Clark Southworth—Southworth is considered most responsible for the development of waveguides. Born in 1890, he studied very-short-wavelength radio waves at Yale University and completed a Ph.D. there in 1923. Southworth then went to work for AT&T, where he specialized in the transmission of very-high-frequency (VHF) EM waves. In 1931, he began to study wave propagation in dielectric rods. Southworth had observed wave propagation in a water-filled copper pipe by early 1932. The next year, he transmitted waves through air-filled copper pipes that were up to 20 feet long using high-frequency vacuum tubes. According to Southworth, the first message sent through a waveguide was, “Send money.” After the waveguide demonstration, he received authorization to construct a 5-in.-diameter guide with a length of 875 ft. for further tests. In 1934, Southworth and his waveguide project were moved to the Bell Telephone Laboratories. Southworth’s waveguides were key to the radar systems used during World War II.

Nikola Tesla—Tesla actually held the first radio patent, in which he described a transmitter and receiver with tuned circuits. His initial demonstration of an apparatus for radio transmission and reception took place in 1893 during a lecture in St. Louis before the National Electric Light Association. This demonstration took place 11 years before Marconi’s first wireless patent. Tesla’s leadership in radio was recognized in June 1944, when the US Supreme Court posthumously ruled in Tesla’s favor in “Tesla v. Marconi,” Case 369. Among this inventor’s many other innovations were polyphase electric power, brushless synchronous and induction motors, the Tesla bladeless turbine and pump, wireless electric-power-transmission concepts, and wireless remote control. Tesla was granted 221 patents worldwide including 113 US patents.

For the full list of legends, check out www.mwrf.com/legends

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