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Main article: "Audion

De Forest's most famous invention was the "grid Audion", which was the first successful three-element ("triode) "vacuum tube, and the first device which could amplify electrical signals. He traced its inspiration to 1900, when, experimenting with a spark-gap transmitter, he briefly thought that the flickering of a nearby gas flame might be in response to electromagnetic pulses. With further tests he soon determined that the cause of the flame fluctuations actually was due to air pressure changes produced by the loud sound of the spark.[17] Still, he was intrigued by the idea that, properly configured, it might be possible to use a flame or something similar to detect radio signals.

After determining that an open flame was too susceptible to ambient air currents, de Forest investigated whether ionized gases, heated and enclosed in a partially evacuated glass tube, could be used instead. In 1905 to 1906 he developed various configurations of glass-tube devices, which he gave the general name of "Audions". The first Audions had only two "electrodes, and on October 25, 1906,[18] de Forest filed a patent for "diode vacuum tube "detector, that was granted U.S. patent number 841387 on January 15, 1907. Subsequently, a third "control" electrode was added, originally as a surrounding metal cylinder or a wire coiled around the outside of the glass tube. None of these initial designs worked particularly well.[19] De Forest gave a presentation of his work to date to the October 26, 1906 New York meeting of the American Institute of Electrical Engineers, which was reprinted in two parts in late 1907 in the Scientific American Supplement.[20] He was insistent that a small amount of residual gas was necessary for the tubes to operate properly. However, he also admitted that "I have arrived as yet at no completely satisfactory theory as to the exact means by which the high-frequency oscillations affect so markedly the behavior of an ionized gas."

De Forest grid Audion from 1906.

In late 1906, de Forest made a breakthrough when he reconfigured the control electrode, changing it from outside the glass to a zig-zag wire inside the tube, positioned in the center between the "cathode ""filament" and the "anode ""plate" electrodes. He reportedly called the zig-zag control wire a ""grid" due to its similarity to the "gridiron" lines on American football playing fields.[21] Experiments conducted with his assistant, "John V. L. Hogan, convinced him that he had discovered an important new radio detector, and he quickly prepared a patent application which was filed on January 29, 1907, and received U.S. patent number 879,532 on February 18, 1908. Because the grid-control Audion was the only configuration to become commercially valuable, the earlier versions were forgotten, and the term "Audion" later became synonymous with just the grid type. It later also became known as the triode.

The grid Audion was the first device to amplify, albeit only slightly, the strength of received radio signals. However, to many observers it appeared that de Forest had done nothing more than add the grid electrode to an existing detector configuration, the "Fleming valve, which also consisted of a filament and plate enclosed in an evacuated glass tube. De Forest passionately denied the similarly of the two devices, claiming his invention was a relay that amplified currents, while the Fleming valve was merely a rectifier that converted alternating current to direct current. (For this reason, de Forest objected to his Audion being referred to as "a valve".) The U.S. courts were not convinced, and ruled that the grid Audion did in fact infringe on the Fleming valve patent, now held by Marconi. On the other hand, Marconi admitted that the addition of the third electrode was a patentable improvement, and the two sides agreed to license each other so that both could manufacture three-electrode tubes in the United States. (De Forest's European patents had lapsed because he did not have the funds needed to renew them).[22]

Because of its limited uses and the great variability in the quality of individual units, the grid Audion would be rarely used during the first half-decade after its invention. In 1908, John V. L. Hogan reported that "The Audion is capable of being developed into a really efficient detector, but in its present forms is quite unreliable and entirely too complex to be properly handled by the usual wireless operator."[23]

Employment at Federal Telegraph[edit]

"California Historical Landmark No. 836, located at the eastern corner of Channing Street and Emerson Avenue in "Palo Alto, California, stands at the former location of the Federal Telegraph laboratory, and references Lee de Forest's development there, in 1911–1913, of "the first vacuum-tube amplifier and oscillator".

In May 1910, the Radio Telephone Company and its subsidiaries were reorganized as the North American Wireless Corporation, but financial difficulties meant that the company's activities had nearly come to a halt. De Forest moved to San Francisco, California, and in early 1911 took a research job at the "Federal Telegraph Company, which produced long-range radiotelegraph systems using high-powered Poulsen arcs.

Audio frequency amplification[edit]

One of de Forest's areas of research at Federal Telegraph was improving the reception of signals, and he came up with the idea of strengthening the "audio frequency output from a grid Audion by feeding it into a second tube for additional amplification. He called this a "cascade amplifier", which eventually consisted of chaining together up to three Audions.

At this time the American Telephone and Telegraph Company was researching ways to amplify telephone signals to provide better long-distance service, and it was recognized that de Forest's device had potential as a telephone line repeater. In mid-1912 an associate, "John Stone Stone, contacted AT&T to arrange for de Forest to demonstrate his invention. It was found that de Forest's "gassy" version of the Audion could not handle even the relatively low voltages used by telephone lines. (Due to the way he constructed the tubes, de Forest's Audions would cease to operate with too high a vacuum.) However, careful research by Dr. Harold D. Arnold and his team at AT&T's Western Electric subsidiary determined that by improving the tube's design, it could be more fully evacuated, and the high vacuum allowed it to successfully operate at telephone line voltages. With these changes the Audion evolved into a modern electron-discharge vacuum tube, using electron flows rather than ions.[24] (Dr. "Irving Langmuir at the General Electric Corporation made similar findings, and both he and Arnold attempted to patent the "high vacuum" construction, but the U.S. Supreme Court ruled in 1931 that this modification could not be patented).

After a delay of ten months, in July, 1913 AT&T, through a third party who disguised his link to the telephone company, purchased the wire rights to seven Audion patents for $50,000. De Forest had hoped for a higher payment, but was again in bad financial shape and was unable to bargain for more. In 1915, AT&T used the innovation to conduct the first transcontinental telephone calls, in conjunction with the Panama-Pacific International Exposition at San Francisco.

Reorganized Radio Telephone Company[edit]

Radio Telephone Company officials had engaged in some of the same stock selling excesses that had taken place at American DeForest, and as part of the U.S. government's crackdown on stock fraud, in March, 1912 de Forest, plus four other company officials, was arrested and charged with "use of the mails to defraud". Their trials took place in late 1913, and while three of the defendants were found guilty, de Forest was acquitted. With the legal problems behind him, de Forest reorganized his company as the DeForest Radio Telephone Company, and established a laboratory at 1391 Sedgewick Avenue in the Highbridge section of the Bronx in New York City. The company's limited finances were boosted by the sale, in October 1914, of the commercial Audion patent rights for radio signalling to AT&T for $90,000, with de Forest retaining the rights for sales for "amateur and experimental use".[25] In October, 1915 AT&T conducted test radio transmissions from the Navy's station in Arlington, Virginia that were heard as far away as Paris and Hawaii.

Audion advertisement, Electrical Experimenter magazine, 1916

The Radio Telephone Company began selling "Oscillion" power tubes to amateurs, suitable for radio transmissions. The company wanted to keep a tight hold on the tube business, and originally maintained a policy that retailers had to require their customers to return a worn out tube before they could get a replacement. This style of business encouraged others to make and sell unlicensed vacuum tubes which did not impose a return policy. One of the boldest was Audio Tron Sales Company founded in 1915 by "Elmer T. Cunningham of San Francisco, whose Audio Tron tubes cost less but were of equal or higher quality. The de Forest company sued Audio Tron Sales, eventually settling out of court.[26]

In April, 1917, the company's remaining commercial radio patent rights were sold to AT&T's Western Electric subsidiary for $250,000.[27] During World War I, the Radio Telephone Company prospered from sales of radio equipment to the military. However, it also became known for the poor quality of its vacuum tubes, especially compared to those produced by major industrial manufacturers such as General Electric and Western Electric.

Regeneration controversy[edit]

Beginning in 1912 there was increased investigation of vacuum-tube capabilities, simultaneously by numerous inventors in multiple countries, who identified additional important uses for the device. These overlapping discoveries led to complicated legal disputes over priority, perhaps the most bitter being one in the United States between de Forest and "Edwin Howard Armstrong over the discovery of "regeneration (also known as the "feedback circuit" and, by de Forest, as the "ultra-audion").[28]

Beginning in 1913 Armstrong prepared papers and gave demonstrations which comprehensively documented how to employ three-element vacuum tubes in circuits that amplified signals to stronger levels than previously thought possible, and which could also generate high power oscillations usable for radio transmissions. In late 1913 Armstrong applied for patents covering the "regenerative circuit, and on October 6, 1914 U.S. patent 1,113,149 was issued for his discovery.[29]

U.S. patent law included a provision for challenging grants if another inventor could prove prior discovery. With an eye on increasing the value of the patent portfolio that would be sold to Western Electric in 1917, beginning in 1915 de Forest filed a series of patent applications that largely copied Armstrong's claims, in the hopes of having the priority of the competing applications upheld by an interference hearing at the patent office. Based on a notebook entry recorded at the time, de Forest asserted that, while working on the cascade amplifier, he had stumbled across the feedback principle on August 6, 1912, which was then used in the spring of 1913 to operate a low-powered transmitter for "heterodyne reception of Federal Telegraph arc transmissions. However, there was also strong evidence that de Forest was unaware of the full significance of this discovery, as shown by his lack of follow-up and continuing misunderstanding of the physics involved. In particular, it appeared that he was unaware of the potential for further development until he became familiar with Armstrong's research. De Forest was not alone in the interference determination — the patent office identified four competing claimants for its hearings, consisting of Armstrong, de Forest, General Electric's Langmuir, and a German, Alexander Meissner, whose application would be seized by the "Office of Alien Property Custodian during World War I.[30]

The subsequent legal proceedings become divided between two groups of court cases. The first court action began in 1919 when Armstrong, with Westinghouse, which purchased his patent, sued the De Forest company in district court for infringement of patent 1,113,149. On May 17, 1921 the court ruled that the lack of awareness and understanding on de Forest's part, in addition to the fact that he had made no immediate advances beyond his initial observation, made implausible his attempt to prevail as inventor.

However, a second series of court cases, which were the result of the patent office interference proceeding, had a different outcome. The interference board had also sided with Armstrong, and de Forest appealed its decision to the District of Columbia district court. On May 8, 1924, that court concluded that the evidence, beginning with the 1912 notebook entry, was sufficient to establish de Forest's priority. Now on the defensive, Armstrong's side tried to overturn the decision, but these efforts, which twice went before the U.S. Supreme Court, in 1928 and 1934, were unsuccessful.[31]

This judicial ruling meant that Lee de Forest was now legally recognized in the United States as the inventor of regeneration. However, much of the engineering community continued to consider Armstrong to be the actual developer, with de Forest viewed as someone who skillfully used the patent system to get credit for an invention to which he had barely contributed. Following the 1934 Supreme Court decision, Armstrong attempted to return his "Institute of Radio Engineers (present day "Institute of Electrical and Electronics Engineers) Medal of Honor, which had been awarded to him in 1917 "in recognition of his work and publications dealing with the action of the oscillating and non-oscillating audion", but the organization's board refused to let him, stating that it "strongly affirms the original award".[32] The practical effect of de Forest's victory was that his company was free to sell products that used regeneration, for during the controversy, which became more a personal feud than a business dispute, Armstrong tried to block the company from even being licensed to sell equipment under his patent.

De Forest regularly responded to articles which he thought exaggerated Armstrong's contributions—animosity that continued even after Armstrong's 1954 suicide. Following the publication of "Carl Dreher's "E. H. Armstrong, the Hero as Inventor" in the August, 1956 Harper's magazine, de Forest wrote the author, describing Armstrong as "exceedingly arrogant, brow beating, even brutal...", and defending the Supreme Court decision in his favor.[33]

Renewed broadcasting activities[edit]

Lee DeForest broadcasting Columbia phonograph records, from page 52 of the November 4, 1916 The Music Trade Review.

In the summer of 1915, the company received an Experimental license for station "2XG,[34] located at its Highbridge laboratory. In late 1916, de Forest renewed the entertainment broadcasts he had suspended in 1910, now using the superior capabilities of vacuum-tube equipment.[35] 2XG's debut program aired on October 26, 1916,[36] as part of an arrangement with the "Columbia Graphophone Company to promote its recordings, which included "announcing the title and 'Columbia Gramophone [sic] Company' with each playing".[37] Beginning November 1, the "Highbridge Station" offered a nightly schedule featuring the Columbia recordings.

These broadcasts were also used to advertise "the products of the DeForest Radio Co., mostly the radio parts, with all the zeal of our catalogue and price list", until comments by Western Electric engineers caused de Forest enough embarrassment to make him decide to eliminate the direct advertising.[38] The station also made the first audio broadcast of election reports — in earlier elections, stations which broadcast results had used Morse code — providing news of the November 1916 "Wilson-Hughes presidential election.[39] The "New York American installed a private wire and bulletins were sent out every hour. About 2000 listeners heard The Star-Spangled Banner and other anthems, songs, and hymns.

With the entry of the United States into World War I on April 6, 1917, all civilian radio stations were ordered to shut down, so 2XG was silenced for the duration of the war. The ban on civilian stations was lifted on October 1, 1919, and 2XG soon renewed operation, with the Brunswick-Balke-Collender company now supplying the phonograph records.[40] In early 1920, de Forest moved the station's transmitter from the Bronx to Manhattan, but did not have permission to do so, so district Radio Inspector "Arthur Batcheller ordered the station off the air. De Forest's response was to return to San Francisco in March, taking 2XG's transmitter with him. A new station, "6XC, was established as "The California Theater station", which de Forest later stated was the "first radio-telephone station devoted solely" to broadcasting to the public.[41]

Later that year a de Forest associate, Clarence "C.S." Thompson, established Radio News & Music, Inc., in order to lease de Forest radio transmitters to newspapers interested in setting up their own broadcasting stations.[42] In August, 1920, The Detroit News began operation of "The Detroit News Radiophone", initially with the callsign "8MK, which later became broadcasting station "WWJ.

Phonofilm sound-on-film process[edit]


In 1921 de Forest ended most of his radio research in order to concentrate on developing an optical "sound-on-film process called "Phonofilm. In 1919 he filed the first patent for the new system, which improved upon earlier work by Finnish inventor "Eric Tigerstedt and the German partnership "Tri-Ergon. Phonofilm recorded the electrical waveforms produced by a microphone photographically onto film, using parallel lines of variable shades of gray, an approach known as "variable density", in contrast to "variable area" systems used by processes such as "RCA Photophone. When the movie film was projected, the recorded information was converted back into sound, in synchronization with the picture.

From October 1921 to September 1922, de Forest lived in "Berlin, Germany, meeting the Tri-Ergon developers (German inventors Josef Engl (1893–1942), Hans Vogt (1890–1979), and Joseph Massolle (1889–1957)) and investigating other European sound film systems. In April 1922 he announced that he would soon have a workable sound-on-film system.[43] On March 12, 1923 he demonstrated Phonofilm to the press;[44] this was followed on April 12, 1923 by a private demonstration to electrical engineers at the Engineering Society Building's Auditorium at 33 West 39th Street in New York City.[45]

In November 1922, de Forest established the De Forest Phonofilm Company, located at 314 East 48th Street in New York City. But none of the "Hollywood movie studios expressed interest in his invention, and because at this time these studios controlled all the major theater chains, this meant de Forest was limited to showing his films in independent theaters. (The Phonofilm Company would file for bankruptcy in September 1926.)

After recording stage performances (such as in vaudeville), speeches, and musical acts, on April 15, 1923 de Forest premiered 18 Phonofilm short films at the independent Rivoli Theater in New York City. Starting in May 1924, "Max and "Dave Fleischer used the Phonofilm process for their "Song Car-Tune series of cartoons—featuring the ""Follow the Bouncing Ball" gimmick. However, de Forest's choice of primarily filming short "vaudeville acts, instead of full-length features, limited the appeal of Phonofilm to Hollywood studios.

De Forest also worked with "Freeman Harrison Owens and "Theodore Case, using their work to perfect the Phonofilm system. However, de Forest had a falling out with both men. Due to de Forest's continuing misuse of Theodore Case's inventions and failure to publicly acknowledge Case's contributions, the Case Research Laboratory proceeded to build its own camera. That camera was used by Case and his colleague Earl Sponable to record President Coolidge on August 11, 1924, which was one of the films shown by de Forest and claimed by him to be the product of "his" inventions.

Believing that de Forest was more concerned with his own fame and recognition than he was with actually creating a workable system of sound film, and because of his continuing attempts to downplay the contributions of the Case Research Laboratory in the creation of Phonofilm, Case severed his ties with de Forest in the fall of 1925. Case successfully negotiated an agreement to use his patents with studio head "William Fox, owner of "Fox Film Corporation, who marketed the innovation as "Fox Movietone. Hollywood introduced a competing method for sound film, the "Vitaphone "sound-on-disc process developed by "Warner Brothers, with the August 6, 1926 release of the "John Barrymore film "Don Juan.

In 1927 and 1928, Hollywood expanded its use of sound-on-film systems, including Fox Movietone and RCA Photophone. Meanwhile, theater chain owner Isadore Schlesinger purchased the "UK rights to Phonofilm and released short films of British "music hall performers from September 1926 to May 1929. Almost 200 Phonofilm shorts were made, and many are preserved in the collections of the "Library of Congress and the "British Film Institute.

Later years and death[edit]

In April 1923, the De Forest Radio Telephone & Telegraph Company, which manufactured de Forest's Audions for commercial use, was sold to a group headed by Edward Jewett of Jewett-Paige Motors, which expanded the company's factory to cope with rising demand for radios. The sale also bought the services of de Forest, who was focusing his attention on newer innovations.[46] De Forest's finances were badly hurt by the stock market crash of 1929, and research in mechanical television proved unprofitable. In 1934, he established a small shop to produce "diathermy machines, and, in a 1942 interview, still hoped "to make at least one more great invention".[47]

De Forest was a vocal critic of many of the developments in the entertainment side of the radio industry. In 1940 he sent an open letter to the "National Association of Broadcasters in which he demanded: "What have you done with my child, the radio broadcast? You have debased this child, dressed him in rags of ragtime, tatters of jive and boogie-woogie." That same year, de Forest and early TV engineer "Ulises Armand Sanabria presented the concept of a primitive "unmanned combat air vehicle using a "television camera and a jam-resistant radio control in a "Popular Mechanics issue.[48] In 1950 his autobiography, Father of Radio, was published, although it sold poorly.

De Forest was the guest celebrity on the May 22, 1957, episode of the television show "This Is Your Life, where he was introduced as "the father of radio and the grandfather of television".[49] He suffered a severe heart attack in 1958, after which he remained mostly bedridden.[50] He died in Hollywood on June 30, 1961, aged 87, and was interred in "San Fernando Mission Cemetery in Los Angeles, California.[51] De Forest died relatively poor, with just $1,250 in his bank account.[52]


The grid Audion, which de Forest called "my greatest invention", and the vacuum tubes developed from it, dominated the field of "electronics for forty years, making possible long-distance telephone service, "radio broadcasting, television, and many other applications. It could also be used as an electronic switching element, and was later used in early digital electronics, including the first electronic computers, although the 1948 invention of the "transistor would lead to microchips that eventually supplanted vacuum-tube technology. For this reason de Forest has been called one of the founders of the "electronic age".[53][54]

De Forest's archives were donated by his widow to the Perham Electronic Foundation, which in 1973 opened the Foothills Electronics Museum at "Foothill College in Los Altos, California. In 1991 the college closed the museum, breaking its contract. The foundation won a lawsuit and was awarded $775,000.[55] The holdings were placed in storage for twelve years, before being acquired in 2003 by History San José and put on display as The Perham Collection of Early Electronics.[56]

Awards and recognition[edit]

Personal life[edit]


Mary Mayo, his third wife

De Forest was married four times, with the first three marriages ending in divorce:


De Forest was a conservative Republican and fervent anti-communist and anti-fascist. In 1932, in the midst of the Great Depression, he voted for Franklin Roosevelt, but later came to resent him, calling Roosevelt America's "first Fascist president". In 1949, he "sent letters to all members of Congress urging them to vote against "socialized medicine, federally subsidized housing, and an excess profits tax". In 1952, he wrote to newly elected Vice President "Richard Nixon, urging him to "prosecute with renewed vigor your valiant fight to put out Communism from every branch of our government". In December 1953, he cancelled his subscription to "The Nation, accusing it of being "lousy with Treason, crawling with Communism."[60]

Religious views[edit]

Although raised in a strongly religious Protestant household, de Forest later became an agnostic. In his autobiography, he wrote that in the summer of 1894 there was an important shift in his beliefs: "Through that Freshman vacation at Yale I became more of a philosopher than I have ever since. And thus, one by one, were my childhood's firm religious beliefs altered or reluctantly discarded."


De Forest was given to expansive predictions, many of which were not borne out, but he also made many correct predictions, including microwave communication and cooking.


Patent images in "TIFF format

See also[edit]


  1. ^ Lee De Forest in the "1900 US Census in "Milwaukee, Wisconsin
  2. ^ Lee De Forest in the "1920 US Census in the "Bronx, New York
  3. ^ Father of Radio: The Autobiography of Lee de Forest, 1950.
  4. ^ The two Institutes merged in 1940 to become the "Illinois Institute of Technology "physics department.
  5. ^ "Wireless Telegraphy That Sends No Messages Except By Wire", New York Herald, October 28, 1901, page 4.
  6. ^ De Forest, page 126.
  7. ^ "Cuss Words in the Wireless", New York Sun, August 27, 1903, page 1.
  8. ^ A Modern Campaign: War and Wireless in the Far East by David Fraser, 1905.
  9. ^ Inventing American Broadcasting: 1899-1922 by Susan J. Douglas, 1987, page 97.
  10. ^ Wireless Communication in the United States: The Early Development of American Radio Operating Companies by Thorn L. Mayes, 1989, page 44.
  11. ^ "Reporting Yacht Races by Wireless Telephony", Electrical World, August 10, 1907, pages 293–294.
  12. ^ History of Communications-Electronics in the United States Navy by Captain L. S. Howeth, USN (Retired), 1963, "The Radio Telephone Failure", pages 169–172.
  13. ^ "Barnard Girls Test Wireless 'Phones", New York Times, February 26, 1909, page 7.
  14. ^ "Today in History, Jan 13". Retrieved 2008-06-24. 
  15. ^ The MetOpera Database (archives)
  16. ^ "Radio Telephone Experiments", Modern Electrics, May, 1910, page 63.
  17. ^ Father of Radio: The Autobiography of Lee de Forest, 1950, page 114. The notebook recordings of the 1900 experiments, including the determination that the flickering was due to sound only, are reproduced on this page.
  18. ^ US 841387, De Forest, Lee, "Device for Amplifying Feeble Electrical Currents", issued 15 January 1907 
  19. ^ "What Everyone Should Know About Radio History: Part II" by J. H. Morecroft, Radio Broadcast, August, 1922, page 299: "[De Forest] took out a patent in 1905 on a bulb having two hot filaments connected in a peculiar manner, the intended functioning of which is not at all apparent to one comprehending the radio art."
  20. ^ "The Audion: A New Receiver for Wireless Telegraphy" by Lee de Forest, Scientific American Supplement: No. 1665, November 30, 1907, pages 348–350 and No. 1666, December 7, 1907, pages 354–356.
  21. ^ An alternate explanation was given by early associate Frank Butler, who stated that de Forest coined the term because the control electrode looked "just like a roaster grid". ("How the Term 'Grid' Originated", Communications magazine, December, 1930, page 41.)
  22. ^ DeForest, page 322.
  23. ^ "The Audion; A Third Form of the Gas Detector" by John L. Hogan, Jr., Modern Electrics, October, 1908, page 233.
  24. ^ The Continuous Wave: Technology and American Radio, 1900-1932 by Hugh G. J. Aitken, 1985, pages 235–244.
  25. ^ DeForest, page 327.
  26. ^ Tyne, Gerald E. J. (1977). The Saga of the Vacuum Tube. Indianapolis, IN: Howard W. Sams & Company. pp. 119 and 162. "ISBN "0-672-21471-7. 
  27. ^ DeForest, page 340.
  28. ^ Armstrong, Edwin H. "Edwin Armstrong: Pioneer of the Airwaves". Living Legacies. Columbia University. Retrieved 2015-10-30. 
  29. ^ Empire of the Air by Tom Lewis, 1991, pages 77, 87.
  30. ^ Ibid., page 192.
  31. ^ Ibid., pages 193–198, 203.
  32. ^ Armstrong, Edwin H. "Biography". Encyclopædia Britannica. Encyclopædia Britannica. Retrieved 2015-10-30. 
  33. ^ Lewis, Tom (1991). Empire of the Air (first ed.). Harper Collins. pp. 218–219. "ISBN "0-06-018215-6. 
  34. ^ "Special Land Stations", Radio Service Bulletin, July, 1915, page 3. The "2" in 2XG's callsign indicated that the station was located in the 2nd Radio Inspection district, while the "X" signified that it held an Experimental license.
  35. ^ De Forest, page 243. He noted that he had been "totally unaware of the fact that in the little audion tube, which I was then using only as a radio detector, lay dormant the principle of oscillation which, had I but realized it, would have caused me to unceremoniously dump into the ash can all of the fine arc mechanisms which I had ever constructed..."
  36. ^ "Columbia Used to Demonstrate Wireless Telephone", The Music Trade Review, November 4, 1916, page 52.
  37. ^ De Forest, page 337.
  38. ^ Ibid., pages 337-338.
  39. ^ "Election Returns Flashed by Radio to 7,000 Amateurs", The Electrical Experimenter, January, 1917, page 650.
  40. ^ De Forest, page 350.
  41. ^ "'Broadcasting' News by Radiotelephone" (letter from Lee de Forest), Electrical World, April 23, 1921, page 936.
  42. ^ The initial advertisements for Radio News & Music, Inc., appeared on page 20 of the March 13, 1920 The Fourth Estate, and page 202 of the March 18, 1920 Printers' Ink.
  43. ^ Lee de Forest and Phonofilm at Virtual Broadway website
  44. ^ Randy Alfred, Wired magazine (March 12, 2008)
  45. ^ ASCE website entry
  46. ^ "Auto Interests Buy DeForest Radio Co.," The New York Times, April 6, 1923, page 19.
  47. ^ "'Magnificent Failure'" by Samuel Lubell, Saturday Evening Post, January 31, 1942, page 49).
  48. ^ "Robot Television Bomber" Popular Mechanics June 1940
  49. ^ Highlights of this episode, as well as a film clip of his 1940 NAB letter, are included in the 1992 "Ken Burns PBS documentary "Empire of the Air: The Men Who Made Radio.
  50. ^ Empire of the Air: The Men Who Made Radio. PBS: 1992.
  51. ^ "Lee De Forest, 87, Radio Pioneer, Dies; Lee De Forest, Inventor, Is Dead at 87". New York Times. July 2, 1961. "Hollywood, California, July 1, 1961. Dr. Lee De Forest, the inventor known as the father of radio, died last night at his home. He was 87 years old. 
  52. ^ Empire of the Air: The Men Who Made Radio
  53. ^ Quantum Generations: A History of Physics in the Twentieth Century by Helge Kragh, 2002, page 127: "...De Forest's invention of the triode (or "audion") was the starting point of the electronic age."
  54. ^ Dawn of the Electronic Age by Frederick Nebeker, 2009, page 15: "The triode vacuum-tube is one of the small number of technical devices... that have radically changed human culture. It defined a new realm of technology, that of electronics..."
  55. ^ Millard, Max (October 1993). "Lee de Forest, Class of 1893:Father of the Electronics Age". Northfield Mount Hermon Alumni Magazine. Retrieved 2011-01-20. 
  56. ^ "The Perham Collection". History San José. 2011. Archived from the original on April 26, 2015. Retrieved March 22, 2016. 
  57. ^ IEEE Global History Network (2011). "IEEE Medal of Honor". IEEE History Center. Retrieved 7 July 2011. 
  58. ^ The 32nd Academy Awards: Memorable Moments.
  59. ^ Hollywood Walk of Fame: Lee De Forest.
  60. ^ James A. Hijya, Lee De Forest and the Fatherhood of Radio (1992), Lehigh University Press, pages 119-120
  61. ^ Campbell, Richard, Christopher R. Martin, and Bettina Fabos. "Sounds and Images." Media and Culture: An Introduction to Mass Communication. Boston: Bedford/St. Martin's, 2000. 113, additional text.
  62. ^ a b c "Dawn of the Electronic Age". "Popular Mechanics. January 1952. Retrieved 2007-07-21. 
  63. ^ Gawlinski, Mark (2003). Interactive television production. Focal Press. p. 89. "ISBN "0-240-51679-6. 
  64. ^ De Forest Says Space Travel Is Impossible, Lewiston Morning Tribune via Associated Press, February 25, 1957

Further reading[edit]

External links[edit]

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