Lee de Forest Inventions Information

Lee de Forest (August 26, 1873 – June 30, 1961) was an American inventor, self-described "Father of Radio", and a pioneer in the development of sound-on-film recording used for motion pictures. He had over 180 patents, but also a tumultuous career—he boasted that he made, then lost, four fortunes. He was also involved in several major patent lawsuits, spent a substantial part of his income on legal bills, and was even tried (and acquitted) for mail fraud. His most famous invention, in 1906, was the three-element "Audion" (triode) vacuum tube, the first practical amplification device. Although De Forest had only a limited understanding of how it worked, it was the foundation of the field of electronics, making possible radio broadcasting, long distance telephone lines, and talking motion pictures, among countless other applications.

Lee de Forest was born in 1873 in Council Bluffs, Iowa, the son of Anna Margaret (née Robbins) and Henry Swift DeForest. He was a direct descendant of Jessé de Forest, the leader of a group of Walloon Huguenots who fled Europe in the 17th century due to religious persecution.

De Forest's father was a Congregational Church minister who hoped his son would also become a pastor. In 1879 the elder de Forest became president of the American Missionary Association's Talladega College in Talladega, Alabama, a school "open to all of either sex, without regard to sect, race, or color", and which educated primarily African-Americans. Many of the local white citizens resented the school and its mission, and Lee spent most of his youth in Talladega isolated from the white community, with several close friends among the black children of the town.

De Forest prepared for college by attending Mount Hermon Boys' School in Mount Hermon, Massachusetts for two years, beginning in 1891. In 1893, he enrolled in a three-year course of studies at Yale University's Sheffield Scientific School in New Haven, Connecticut, on a $300 per year scholarship that had been established for relatives of David de Forest. Convinced that he was destined to become a famous—and rich—inventor, and perpetually short of funds, he sought to interest companies with a series of devices and puzzles he created, and expectantly submitted essays in prize competitions, all with little success.

After completing his undergraduate studies, in September 1896 de Forest began three years of postgraduate work. However, his electrical experiments had a tendency to blow fuses, causing building-wide blackouts. Even after being warned to be more careful, he managed to douse the lights during an important lecture by Professor Charles Hastings, who responded by having de Forest expelled from Sheffield.

With the outbreak of the Spanish–American War in 1898, de Forest enrolled in the Connecticut Volunteer Militia Battery as a bugler, but the war ended and he was mustered out without ever leaving the state. He then completed his studies at Yale's Sloane Physics Laboratory, earning a Doctorate in 1899 with a dissertation on the "Reflection of Hertzian Waves from the Ends of Parallel Wires", supervised by theoretical physicist Willard Gibbs.

De Forest was convinced there was a great future in radiotelegraphic communication (then known as "wireless telegraphy"), but Italian Guglielmo Marconi, who received his first patent in 1896, was already making impressive progress in both Europe and the United States. One drawback to Marconi's approach was his use of a coherer as a receiver, which, while providing for permanent records, was also slow (after each received Morse code dot or dash, it had to be tapped to restore operation), insensitive, and not very reliable. De Forest was determined to devise a better system, including a self-restoring detector that could receive transmissions by ear, thus making it capable of receiving weaker signals and also allowing faster Morse code sending speeds.

After making unsuccessful inquiries about employment with Nikola Tesla and Marconi, de Forest struck out on his own. His first job after leaving Yale was with the Western Electric Company's telephone lab in Chicago, Illinois. While there he developed his first receiver, which was based on findings by two German scientists, Drs. A. Neugschwender and Emil Aschkinass. Their original design consisted of a mirror in which a narrow, moistened slit had been cut through the silvered back. Attaching a battery and telephone receiver, they could hear sound changes in response to radio signal impulses. De Forest, along with Ed Smythe, a co-worker who provided financial and technical help, developed variations they called "responders".

A series of short-term positions followed, including three unproductive months with Professor Warren S. Johnson's American Wireless Telegraph Company in Milwaukee, Wisconsin, and work as an assistant editor of the Western Electrician in Chicago. With radio research his main priority, de Forest next took a night teaching position at the Lewis Institute, which freed him to conduct experiments at the Armour Institute. By 1900, using a spark-coil transmitter and his responder receiver, de Forest expanded his transmitting range to about seven kilometers (four miles). Professor Clarence Freeman of the Armour Institute became interested in de Forest's work and developed a new type of spark transmitter.

De Forest soon felt that Smythe and Freeman were holding him back, so in the fall of 1901 he made the bold decision to go to New York to compete directly with Marconi in transmitting race results for the International Yacht races. Marconi had already made arrangements to provide reports for the Associated Press, which he had successfully done for the 1899 contest. De Forest contracted to do the same for the smaller Publishers' Press Association.

The race effort turned out to be an almost total failure. The Freeman transmitter broke down — in a fit of rage, de Forest threw it overboard — and had to be replaced by an ordinary spark coil. Even worse, the American Wireless Telephone and Telegraph Company, which claimed its ownership of Amos Dolbear's 1886 patent for wireless communication meant it held a monopoly for all wireless communication in the United States, had also set up a powerful transmitter. None of these companies had effective tuning for their transmitters, so only one could transmit at a time without causing mutual interference. Although an attempt was made to have the three systems avoid conflicts by rotating operations over five-minute intervals, the agreement broke down, resulting in chaos as the simultaneous transmissions clashed with each other. De Forest ruefully noted that under these conditions the only successful "wireless" communication was done by visual semaphore "wig-wag" flags. (The 1903 International Yacht races would be a repeat of 1901 — Marconi worked for the Associated Press, de Forest for the Publishers' Press Association, and the unaffiliated International Wireless Company (successor to 1901's American Wireless Telephone and Telegraph) operated a high-powered transmitter that was used primarily to drown out the other two.)

Despite this setback, de Forest remained in the New York City area, in order to raise interest in his ideas and capital to replace the small working companies that had been formed to promote his work thus far. In January 1902 he met a promoter, Abraham White, who would become de Forest's main sponsor for the next five years. White envisioned bold and expansive plans that enticed the inventor — however, he was also dishonest and much of the new enterprise would be built on wild exaggeration and stock fraud. To back de Forest's efforts, White incorporated the American DeForest Wireless Telegraph Company, with himself as the company's president, and de Forest the Scientific Director. The company claimed as its goal the development of "world-wide wireless".

The original "responder" receiver (also known as the "goo anti-coherer") proved to be too crude to be commercialized, and de Forest struggled to develop a non-infringing device for receiving radio signals. In 1903, Reginald Fessenden demonstrated an electrolytic detector, and de Forest developed a variation, which he called the "spade detector", claiming it did not infringe on Fessenden's patents. Fessenden, and the U.S. courts, did not agree, and court injunctions enjoined American De Forest from using the device.

Meanwhile, White set in motion a series of highly visible promotions for American DeForest: "Wireless Auto No.1" was positioned on Wall Street to "send stock quotes" using an unmuffled spark transmitter to loudly draw the attention of potential investors, in early 1904 two stations were established at Wei-hai-Wei on the Chinese mainland and aboard the Chinese steamer SS Haimun, which allowed war correspondent Captain Lionel James of The Times of London to report on the brewing Russo-Japanese War, and later that year a tower, with "DEFOREST" arrayed in lights, was erected on the grounds of the Louisiana Purchase Exposition in Saint Louis, Missouri, where the company won a gold medal for its radiotelegraph demonstrations. (Marconi withdrew from the Exposition when he learned de Forest would be there).

The company's most important early contract was the construction, in 1905–1906, of five high-powered radiotelegraph stations for the U.S. Navy, located in Panama, Pensacola and Key West, Florida, Guantanamo, Cuba, and Puerto Rico. It also installed shore stations along the Atlantic Coast and Great Lakes, and equipped shipboard stations. But the main focus was selling stock at ever more inflated prices, spurred by the construction of promotional inland stations. Most of these inland stations had no practical use and were abandoned once the local stock sales slowed.

De Forest eventually came into conflict with his company's management. His main complaint was the limited support he got for conducting research, while company officials were upset with de Forest's inability to develop a practical receiver free of patent infringement. (This problem was finally resolved with the invention of the carborundum crystal detector by another company employee, General Henry Harrison Chase Dunwoody). On November 28, 1906, in exchange for $1000 (half of which was claimed by an attorney) and the rights to some early Audion detector patents, de Forest turned in his stock and resigned from the company that bore his name. American DeForest was then reorganized as the United Wireless Telegraph Company, and would be the dominant U.S. radio communications firm, albeit propped up by massive stock fraud, until its bankruptcy in 1912.

De Forest moved quickly to re-establish himself as an independent inventor, working in his own laboratory in the Parker Building in New York City. The Radio Telephone Company was incorporated in order to promote his inventions, with James Dunlop Smith, a former American DeForest salesman, as president, and de Forest the vice president. (De Forest preferred the term "radio", which up to now had been primarily used in Europe, over "wireless".)

At the 1904 Louisiana Purchase Exposition, Valdemar Poulsen had presented a paper on an arc transmitter, which unlike the discontinuous pulses produced by spark transmitters, created steady "continuous wave" signals that could be used for amplitude modulated (AM) audio transmissions. Although Poulsen had patented his invention, de Forest claimed to have come up with a variation that allowed him to avoid infringing on Poulsen's work. Using his "sparkless" arc transmitter, de Forest first transmitted audio across a lab room on December 31, 1906, and by February was making experimental transmissions, including music produced by Thaddeus Cahill's telharmonium, that were heard throughout the city.

On July 18, 1907, de Forest made the first ship-to-shore transmissions by radiotelephone — race reports for the Annual Inter-Lakes Yachting Association (I-LYA) Regatta held on Lake Erie — which were sent from the steam yacht Thelma to his assistant, Frank E. Butler, located in the Fox's Dock Pavilion on South Bass Island. De Forest also interested the U.S. Navy in his radiotelephone, which placed a rush order to have 26 arc sets installed for its Great White Fleet around-the-world voyage that began in late 1907. However, at the conclusion of the circumnavigation the sets were declared to be too unreliable to meet the Navy's needs and removed.

The company set up a network of radiotelephone stations along the Atlantic coast and the Great Lakes, for coastal ship navigation. However, the installations proved unprofitable, and by 1911 the parent company and its subsidiaries were on the brink of bankruptcy.

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