Definitions

Reginald_Fessenden

Reginald Fessenden

Reginald Aubrey Fessenden (October 6, 1866July 22, 1932), born in East Bolton, Quebec, Canada, was a Canadian inventor, best known for his work in early radio. At the age of fourteen, Bishop's College School in Lennoxville, Quebec granted Fessenden a mathematics mastership. In late 1886, Fessenden began working directly for Thomas Edison at the inventor's new Laboratory in West Orange, New Jersey. Fessenden quickly made major advances, especially in receiver design, as he worked to develop audio reception of signals. From 1890 to 1900, Fessenden worked at several manufacturing companies and became a professor of electrical engineering at Purdue University in 1892 and then chair of the electrical engineering department of the University of Pittsburgh in 1893. By 1900, Fessenden was working for the United States Weather Bureau where he evolved the heterodyne principle where two signals combined produce a third audible tone. While there, Fessenden, experimenting with a high-frequency spark transmitter, successfully transmitted speech on December 23, 1900 over a distance of about 1.6 kilometers (one mile), which appears to have been the first audio radio transmission.

The National Electric Signaling Company (NESCO) was financed to carry on Fessenden's research, including the development of both a high-power rotary-spark transmitter for long-distance radiotelegraph service, and a lower-powered continuous-wave alternator-transmitter, which could be used for both telegraphic and audio transmissions. Fessenden felt that, ultimately, a continuous-wave transmitter—one that produced a pure sine-wave signal on a single frequency—would be far more efficient, particularly because it could be used for quality audio transmissions. Fessenden contracted with General Electric to help design and produce a series of high-frequency alternator-transmitters.

On 21 December 1906, Fessenden made an extensive demonstration of the new alternator-transmitter at Brant Rock, showing its utility for point-to-point wireless telephony, including interconnecting his stations to the wire telephone network. A few days later, two additional demonstrations took place, which appear to be the first audio radio broadcasts of entertainment and music ever made to a general audience. On the evening of 24 December 1906 (Christmas Eve), Fessenden used the alternator-transmitter to send out a short program from Brant Rock, which included his playing the song O Holy Night on the violin and reading a passage, Luke Chapter 2, from the Bible. On 31 December, New Year's Eve, a second short program was broadcast. The main audience for both these transmissions was an unknown number of shipboard radio operators along the Atlantic Coast. Although now seen as a landmark, these two broadcasts were barely noticed at the time and soon forgotten.

The technical achievements made by Fessenden were not matched by financial success. There were growing strains between Fessenden and the company owners, and finally Fessenden was dismissed from NESCO in January 1911. Fessenden won the initial court trial and was awarded damages, however, NESCO prevailed on appeal. The company was sold to Westinghouse in 1920, and the next year its assets, including numerous important Fessenden patents, were sold to the Radio Corporation of America, which also inherited the Fessenden legal proceedings.

After 1920, audio radio broadcasting became widespread, using vacuum tube transmitters rather than the alternator, but employing the continuous-wave AM signals that Fessenden had helped introduce in 1906. Although Fessenden ceased radio activities after his dismissal from NESCO in 1911, he continued to work in other fields. An inveterate tinkerer, Fessenden eventually became the holder of more than 500 patents. After settling his lawsuit with RCA, Fessenden purchased a small estate called "Wistowe" in Bermuda.

His legacy to radio include three of his most notable achievements: the first audio transmission by radio (1900), the first two-way transatlantic radio transmission (1906), and the first radio broadcast of entertainment and music (1906).

Early years

Reginald Aubrey Fessenden was born October 6, 1866, in East Bolton, Quebec, Canada, the eldest of Joseph Elisha Fessenden and Clementina Trenholme Fessenden's four children. Joseph Fessenden was a priest of the Church of England in Canada, and through the years the family moved to a number of postings within the Province of Ontario. While growing up, Reginald was an accomplished student. In 1877, at the age of eleven, he attended Trinity College School in Port Hope, Ontario for two years. At the age of fourteen, Bishop's College School in Lennoxville, Quebec granted Fessenden a mathematics mastership. At this time, Bishop's College School was a feeder school of Bishop's University and shared the same campus and buildings. In June 1878, the school had an enrolment of only 43 boys. Thus, while Fessenden was only a teenager, he was teaching mathematics to the young children at the school while simultaneously studying with the older students at Bishop's University. Total enrolment at the university for the school year 1883-84 was twenty-five (all male) students. At the age of eighteen, Fessenden left Bishop's without having been awarded a degree, even though he had "done substantially all the work necessary". (This lack of a degree may have hurt Fessenden's employment opportunities—when McGill University established an electrical engineering department, Fessenden was turned down on an application to be the chairman, in favor of an American.)

The next two years he worked as the principal, and sole teacher, at the Whitney Institute in Bermuda. While there, he became engaged to Helen Trott. They married in September, 1890, and later had a son, Reginald Kennelly Fessenden.

Early work

Fessenden's classical education had provided him with only a limited amount of scientific and technical training. Interested in increasing his skills in the electrical field, he moved to New York City in 1886, with hopes of gaining employment with the famous inventor, Thomas Edison. As recounted in his 1925 Radio News autobiography, his initial attempts were rebuffed—in his first application, Fessenden wrote "Do not know anything about electricity, but can learn pretty quick", to which Edison replied "Have enough men now who do not know about electricity". However, Fessenden persevered, and before the end of the year was hired for a semi-skilled position as an assistant tester for the Edison Machine Works, which was laying underground electrical mains in New York City. He quickly proved his worth, and received a series of promotions, with increasing responsibility for the project. In late 1886, Fessenden began working directly for Edison at the inventor's new Laboratory at in West Orange, New Jersey. A broad range of projects included work in solving problems in chemistry, metallurgy, and electricity. However, in 1890, facing financial problems, Edison was forced to lay off most of the Laboratory employees, including Fessenden.

Taking advantage of his recent practical experience, Fessenden was able to find positions with a series of manufacturing companies. Next, in 1892, he received an appointment as professor for the newly formed Electrical Engineering department at Purdue University in West Lafayette, Indiana—while there he helped the Westinghouse Corporation install the lighting for the 1893 World Columbian Exposition in Chicago. Shortly thereafter, George Westinghouse personally recruited Fessenden for the newly created position of chair of the Electrical Engineering department at the Western University of Pennsylvania, the modern-day University of Pittsburgh.

Radio work

In the late 1890s, reports began to appear about the success Guglielmo Marconi was having in developing a practical radio transmitting and receiving system. Fessenden began limited radio experimentation, and soon came to the conclusion that he could develop a far more efficient system than the spark-gap transmitter and coherer-receiver combination which had been championed by Oliver Lodge and Marconi.

Weather Bureau contract and the first audio radio transmission

In 1900 Fessenden left the University of Pittsburgh to work for the United States Weather Bureau, with the objective of proving the practicality of using a network of coastal radio stations to transmit weather information, thus avoiding the need to use the existing telegraph lines. The contract gave the Weather Bureau access to any devices Fessenden invented, but he would retain ownership of his inventions. Fessenden quickly made major advances, especially in receiver design, as he worked to develop audio reception of signals. His initial success came from a barretter detector, which was followed by the electrolytic detector that consisted of a fine wire dipped in nitric acid, and for the next few years this later device would set the standard for sensitivity in radio reception. As his work progressed, Fessenden also evolved the heterodyne principle, which combined two signals to produce a third audible tone. However, heterodyne reception was not fully practical for a decade after it was invented, since it required a means for producing a stable local signal, which awaited the development of the oscillating vacuum-tube.

The initial work took place at Cobb Island, Maryland, located on the Potomac River about 80 kilometers (50 miles) downstream from Washington, DC. While there, Fessenden, experimenting with a high-frequency spark transmitter, successfully transmitted speech on December 23, 1900 over a distance of about 1.6 kilometers (one mile), which appears to have been the first audio radio transmission. At this time the sound quality was too distorted to be commercially practical, but as a test this did show that with further technical refinements it would become possible to transmit audio using radio signals.

As the experimentation expanded, additional stations were built along the Atlantic Coast in both North Carolina and Virginia. However, in the midst of promising advances, Fessenden became embroiled in disputes with his sponsor. In particular, he charged that Bureau Chief Willis Moore had attempted to gain a half-share of the patents — Fessenden refused to sign over the rights, and his work for the Weather Bureau ended in August, 1902. (This incident recalled F. O. J. Smith, a member of the House of Representatives from Maine, who had managed to gain a one-quarter interest in the Morse telegraph.)

Formation of NESCO

At this point, two wealthy Pittsburgh, Pennsylvania businessmen, Hay Walker, Jr., and Thomas H. Given, financed the formation of the National Electric Signaling Company (NESCO), to carry on Fessenden's research, including the development of both a high-power rotary-spark transmitter for long-distance radiotelegraph service, and a lower-powered continuous-wave alternator-transmitter, which could be used for both telegraphic and audio transmissions. Marshfield's Brant Rock, Massachusetts became the center of operations for the new company.

Rotary-spark transmitter and the first two-way transatlantic transmission

It was decided to try to establish a transatlantic radiotelegraph service, and, in January, 1906, employing his rotary-spark transmitters, Fessenden made the first successful two-way transatlantic transmission, exchanging Morse code messages between a station constructed at Brant Rock and an identical one built at Machrihanish, Scotland. (Marconi had only achieved one-way transmissions at this time.) However, the transmitters could not bridge this distance during daylight hours or in the summer, so work was suspended until later in the year. Then, on December 6, 1906, "owing to the carelessness of one of the contractors employed in shifting some of the supporting cables", the Machrihanish radio tower collapsed, abruptly ending the transatlantic work before it could ever go into commercial service.

Alternator-transmitter and the first audio radio broadcast

The development of a rotary-spark transmitter was something of a stop-gap measure, to be used until a superior approach could be perfected. Fessenden felt that, ultimately, a continuous-wave transmitter—one that produced a pure sine wave signal on a single frequency—would be far more efficient, particularly because it could be used for quality audio transmissions. His design idea was to take a basic electrical alternator, which normally operated at speeds that produced alternating current of at most a few hundred hertz, and greatly speed it up in order to create electrical currents at tens of kilohertz. Thus, the high-speed alternator would produce a steady radio signal when connected to an aerial. Then, by simply placing a carbon microphone in the transmission line, the strength of the signal could be varied in order to add sounds to the transmission—in other words, amplitude modulation would be used to impress audio on the radio frequency carrier wave. However, it would take many years of expensive development before even a prototype alternator-transmitter would be ready, and a few more years beyond that for high-power versions to become available.

Fessenden contracted with General Electric to help design and produce a series of high-frequency alternator-transmitters. In 1903, Charles Proteus Steinmetz of GE delivered a 10 kHz version which proved of limited use and could not be directly used as a radio transmitter. Fessenden's request for a faster, more powerful unit was assigned to Ernst F. W. Alexanderson, and in August, 1906 he delivered an improved model which operated at a transmitting frequency of approximately 50 kHz, although with far less power than Fessenden's rotary-spark transmitters.

The alternator-transmitter achieved the goal of transmitting quality audio signals, but the lack of any way to amplify the signals meant they were somewhat weak. On December 21, 1906, Fessenden made an extensive demonstration of the new alternator-transmitter at Brant Rock, showing its utility for point-to-point wireless telephony, including interconnecting his stations to the wire telephone network. A detailed review of this demonstration appeared in the The American Telephone Journal.

A few days later, two additional demonstrations took place, which appear to be the first audio radio broadcasts of entertainment and music ever made to a general audience. (Beginning in 1904, the U.S. Navy had broadcast daily time signals and weather reports, but these employed spark transmitters, transmitting in Morse code). On the evening of December 24, 1906 (Christmas Eve), Fessenden used the alternator-transmitter to send out a short program from Brant Rock, which included his playing the song O Holy Night on the violin and reading a passage from the Bible. On December 31, New Year's Eve, a second short program was broadcast. The main audience for both these transmissions was an unknown number of shipboard radio operators along the Atlantic Coast. Although now seen as a landmark, these two broadcasts were barely noticed at the time and soon forgotten—the only first-hand account appears to be a letter Fessenden wrote on January 29, 1932 to his former associate, Samuel M. Kinter. There are no known accounts in any ships radio logs, nor any contemporary literature, of the reported holiday demonstrations. In addition, Fessenden does not appear to have made any additional broadcasts intended for a general audience, and was actually promoting the alternator-transmitter as ideal for point-to-point wireless telephone service. Still, in retrospect, it was an important glimpse of the future of radio. (Although primarily designed for transmissions spanning a few kilometers, on a couple of occasions the test Brant Rock audio transmissions were apparently overheard by NESCO employee James C. Armor across the Atlantic at the Machrihanish site).

Continuing work and dismissal from NESCO

The technical achievements made by Fessenden were not matched by financial success. Walker and Given had hoped to sell NESCO to a larger company such as the American Telephone & Telegraph Company, but were unable to find a buyer. Fessenden's formation of the Fessenden Wireless Company of Canada in Montreal in 1906 may have led to suspicion that he was trying to freeze Walker and Given out of a potentially lucrative competing transatlantic service. There were growing strains between Fessenden and the company owners, and finally Fessenden was dismissed from NESCO in January 1911. He in turn brought suit against NESCO for breach of contract. Fessenden won the initial court trial and was awarded damages, however, NESCO prevailed on appeal. To conserve assets, NESCO went into receivership in 1912, and Samuel Kintner was appointed general manager of the company—the legal stalemate would continue for over 15 years. In 1917, NESCO finally emerged from receivership, and was soon renamed the International Radio Telegraph Company. The company was sold to Westinghouse in 1920, and the next year its assets, including numerous important Fessenden patents, were sold to the Radio Corporation of America, which also inherited the Fessenden legal proceedings. Finally, on March 1, 1928, Fessenden settled his outstanding lawsuits with RCA, receiving a large cash payment.

Ongoing influence

After Fessenden left NESCO, Alexanderson continued to work on alternator-transmitter development at GE, mostly for long range radiotelegraph use. It took many years, but he eventually developed the high-powered Alexanderson alternator capable of transmitting across the Atlantic, and by 1916 the Fessenden-Alexanderson alternator was more reliable for transatlantic communication than spark apparatus. Also, after 1920, audio radio broadcasting became widespread, using vacuum-tube transmitters rather than the alternator, but employing the continuous-wave AM signals that Fessenden had helped introduce in 1906. In 1921, the Institute of Radio Engineers presented Fessenden with its Medal of Honor, and the next year the City of Philadelphia awarded him a John Scott Medal and a cash prize of $800 for his invention in "Continuous Wave Telegraphy and Telephony", and recognized him as "One whose labors had been of great benefit".

Later years

Although Fessenden ceased radio activities after his dismissal from NESCO in 1911, he continued to work in other fields. As early as 1904 he had helped engineer the Niagara Falls power plant for the newly formed Hydro-Electric Power Commission of Ontario. However, his most extensive work was in developing a type of sonar system, the so-called Fessenden oscillator, for submarines to signal each other, as well as a method for locating icebergs, to help avoid another disaster like the one that sank Titanic. At the outbreak of World War I, Fessenden volunteered his services to the Canadian government and was sent to London, England where he developed a device to detect enemy artillery and another to locate enemy submarines.

An inveterate tinkerer, Fessenden eventually became the holder of more than 500 patents. He could often be found in a river or lake, floating on his back, a cigar sticking out of his mouth and a hat pulled down over his eyes. At home he liked to lie on the carpet, a cat on his chest. In this state of relaxation, Fessenden could imagine, invent and think his way to new ideas, including a version of microfilm, that helped him to keep a compact record of his inventions, projects and patents. He patented the basic ideas leading to reflection seismology, a technique important for its use in exploring for petroleum. In 1915 he invented the fathometer, a sonar device used to determine the depth of water for a submerged object by means of sound waves, for which he won Scientific American's Gold Medal in 1929. Fessenden also received patents for tracer bullets, paging, television apparatus, turbo electric drive for ships, and more.

Death and afterwards

After settling his lawsuit with RCA, Fessenden purchased a small estate called "Wistowe" in Bermuda. He died there in 1932 and was interred in the cemetery of St Mark's Church on the island. An editorial in the New York Herald Tribune said:
It sometimes happens, even in science, that one man can be right against the world. Professor Fessenden was that man. He fought bitterly and alone to prove his theories. It was he who insisted, against the stormy protests of every recognized authority, that what we now call radio was worked by continuous waves sent through the ether by the transmitting station as light waves are sent out by a flame. Marconi and others insisted that what was happening was a whiplash effect. The progress of radio was retarded a decade by this error. The whiplash theory passed gradually from the minds of men and was replaced by the continuous wave — one with all too little credit to the man who had been right.

Reginald A. Fessenden House

Fessenden's home at 45 Waban Hill Road in the Chestnut Hill district of Newton, Massachusetts is on the National Register of Historic Places and is also a U.S. National Landmark. He bought the house in 1906 or earlier and owned it for the rest of his life.

Quotations

An inventor is one who can see the applicability of means to supplying demand five years before it is obvious to those skilled in the art.
"The Inventions of Reginald A. Fessenden". (January, 1925). Radio News, p. 1142.

Patents

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  • , "Lead-in Wire for Incandescent Electric Lamps" – 18 February, 1891
  • , "Manufacture of Incandescent Electric Lamps" – 9 June, 1891
  • , "Molding for Electrical Conductors" – 10 October, 1893
  • , "Pencil for Incandescent Lamps" – 12 December, 1899
  • , "Pencil for Incandescent Lamps" – 12 December, 1899
  • , "Incandescent Lamp" – 12 December, 1899
  • , "Incandescent Lamp" – 12 December, 1899
  • , "Incandescent Lamp" – 12 December, 1899
  • , "Induction Coil for X-ray Apparatus" – 6 March, 1900
  • , "X-ray Apparatus" – 1 May, 1900
  • , "Incandescent Lamp" – 29 May, 1900
  • , "Induction-coil" – July, 1900
  • , "Incandescent Lamp" – 19 March, 1901
  • , "Wireless Telegraphy" – 12 August, 1902
  • , "Apparatus for Wireless Telegraphy" – 12 August, 1902
  • , "Wireless Telegraphy" – 12 August, 1902
  • , "Wireless Telegraphy" – 12 August, 1902
  • , "Conductor for Wireless Telegraphy" – 12 August, 1902
  • , "Wireless Signaling" (heterodyne principle) – 12 August, 1902
  • , "Apparatus for Wireless Telegraphy" (compressed air spark gap transmitter) – 12 August, 1902
  • , "Wireless Signaling", – 12 August, 1902 (transmit-receive switch)
  • , "Wireless Signaling", – 12 August, 1902
  • , "Current Actuated Wave Responsive Device" ("barretter" detector) – August, 1902
  • , "Signaling by Electromagnetic Waves" – issued 12 August 1902
  • , "Signaling by Electromagnetic Waves" (ground plane) – 12 August, 1902
  • , "Apparatus for Signaling by Electromagnetic Waves" (voice modulation of 50 kHz alternator – continuous wave transmitter) – 12 August, 1902
  • , "Current Operatied Receiver for Electromagnetic Waves" – 2 December, 1902
  • , "Selective Signaling by Electromagnetic Waves" (multiplex transmission and reception) – 2 December, 1902
  • , "Transmission and Receipt of Signals" – 5 May, 1903
  • , "Selective Signaling by Electromagnetic Waves" – 5 May, 1903
  • , "Receiver for Electromagnetic Waves" – 5 May, 1903
  • , "Receiver for Signaling" – 5 May, 1903
  • , "Signaling by Electromagnetic Waves" – 5 May, 1903
  • , "Signaling by Electromagnetic Waves" – May, 1903
  • , "Receiver for Electromagnetic Waves" (improved "barretter" -- actually electrolytic detector) – May, 1903
  • , "Signaling by Electromagnetic Waves" – 9 June, 1903
  • , "Method of Utilizing the Energy of Waves" – 16 June, 1903
  • , "Signaling by Electromagnetic Waves" – 27 October, 1903
  • , "Signaling by Electromagnetic Waves" – 27 October, 1903
  • , "Selective Signaling" – 23 February, 1904
  • , "Signaling by Electromagnetic Waves" – 23 February, 1904
  • , "Signaling by Electromagnetic Waves" – 8 March, 1904
  • , "Signaling by Electromagnetic Waves" – 8 March, 1904
  • , "Apparatus for Transmitting and Receiving Signals" – 6 December, 1904
  • , "Receiver for Electromagnetic Waves" (sealed/pressurized electrolytic detector) – 4 July, 1905
  • , "Signaling by Electromagnetic Waves" – 4 July, 1905
  • , "Signaling by Electromagnetic Waves" – 4 July, 1905
  • , "Aerial for Wireless Signaling" (shows insulated base) – 4 July, 1905
  • , "Signaling by Electromagnetic Waves" (shows the Brant Rock tower) – 4 July, 1905
  • , "Wireless Telegraphy" – 4 July, 1905
  • , "Condenser" – 4 July, 1905
  • , "Capacity" – 13 March, 1906
  • , "Wireless Telegraphy" – 1 September, 1908
  • , "Electric Signaling" – 16 March, 1909
  • , "Receiver for Electromagnetic Waves" – 30 March, 1909
  • , "Apparatus for Wireless Signaling" – 13 April, 1909
  • , "Signaling by Electromagnetic Waves" – 20 July, 1909
  • , "Producing High Frequency Oscillations" – 24 August, 1909
  • , "Method for Cleaning Guns" – 2 November, 1909
  • , "Method for Determining Positions of Vessels" – 30 November, 1909
  • , "Wireless Telegraphy" (antenna tuning) – 1 February, 1910
  • , "Signaling by Electromagnetic Waves" – 26 April, 1910
  • , "Wireless Signaling" – 7 June, 1910
  • , "Receiver for Electromagnetic Waves" – 21 June, 1910
  • , "Method of Signaling" – 21 June, 1910
  • , "Improvements in Wireless Telegraphy" – 1 November, 1910
  • , "Electrical Signaling" – 20 December, 1910
  • , "Signaling by Electromagnetic Waves" – 18 July, 1911
  • , "Signaling by Electromagnetic Waves" – 29 August, 1911
  • , "Electrical Signaling" – 29 August, 1911
  • , "Determining Positions of Vessels" – 29 August, 1911
  • , "Means for the Transmission of Energy by Electromagnetic Waves" – 30 January, 1912
  • , "Signaling" – 5 March, 1912
  • , "Signaling by Electromagnetic Waves" – 12 March, 1912
  • , "Wireless Signaling" – 9 April, 1912
  • , "Wireless Telegraphy" – 13 August, 1912
  • , "High Frequency Electrical Conductor" – 1 October, 1912
  • , "Contact for Electromagnetic Mechanism" – 31 December, 1912
  • , "Electrical Signaling Apparatus" – 1925
  • , "Wireless Telegraphy" (antenna tuning)– April, 1913
  • , "Signaling by Sound and Other Longitudinal Elastic Impulses" – 1 September, 1914
  • , "Agricultural Engineering" – 22 December, 1914
  • , "Sending Mechanism for Electromagnetic Waves" – 2 February, 1916
  • , "Apparatus for Converting Heat Into Work" – 16 March, 1915
  • , "Electric Signaling" – 23 March, 1915
  • , "Wireless Telegraphy" – 23 March, 1915
  • , "Method of Transmitting and Receiving Electrical Energy" – 1 June, 1915
  • , "Improvements in Wireless Telegraphy" – 20 July, 1915
  • , "Apparatus for the transmission by electrical oscillation" – 12 October, 1915
  • , "Apparatus for Generating and Receiving Electromagnetic Waves" – 26 October, 1915
  • , "Signaling Apparatus Aerial Navagation" – 26 October, 1915
  • , "Apparatus for Wireless Signaling" – 28 December, 1915
  • , "Apparatus for Producing High Frequency Oscillations" – 4 January, 1916
  • , "Means of Transmitting Intelligence" – 8 February, 1916
  • , "Method of Transmitting Energy by Electromagnetic Waves" – 15 February, 1916
  • , "Electromagnetic Indicator" – 15 February, 1916
  • , "Wireless Signaling" – 11 April, 1916
  • , "Signaling by Electromagnetic Waves" – 30 May, 1916
  • , "Method of Using Pulverulent Matter As Fuel" – 11 July, 1916
  • , "Method and Apparatus for Submarine Signaling" – 5 December, 1916
  • , "Submarine, Subterranean, and Aerial Telephony" – 16 January, 1917
  • , "Apparatus for Phonograph Kinetoscopes" – 23 January, 1917
  • , "Power Plant" – 27, February, 1917
  • , "Method and Apparatus for Finding Ore Bodies" – 18 September, 1917
  • , "Method for Storing Power" – 20 November, 1917
  • , "Method and Apparatus for Producing Alternating Currents" – 7 May, 1918
  • , "Method and Apparatus for Agricultural Engineering" – 11 June, 1918
  • , "Method and Apparatus for Transmitting and Receiving Sound Waves Through Ground" – 25 June, 1918
  • , "Apparatus for Submarines" – 4 January, 1919
  • , "Method of and Apparatus for Obtaining Increased Circulation" – 14 October, 1919
  • , "Detecting and Locating Ships" – 21 October, 1919
  • , "Method of and Apparatus for Detecting Low Frequency Impulses" – 3 August, 1920
  • , "Method and Apparatus for Submatine Signaling" – 3 August, 1920
  • , "Method and Apparatus for Sound Insulation" – 3 August, 1920
  • , "Method and Apparatus for Detecting Submarines" – 10 August, 1920
  • , "Wireless Direction Finder" – 12 April, 1921
  • , "Method and Apparatus for Signaling and Otherwise Utilizing Radiant Impulses" – 5 July, 1921
  • , "Sound-Signaling" – 5 July, 1921
  • , "Apparatus for Submarine Signaling" – 3 August, 1920
  • , "Method and Apparatus for Submarine Signaling and Detection" – 3 August, 1920
  • , "Submarine Signaling" – 18 October, 1920
  • , "Method and Apparatus for Submarine Signaling" – 18 October, 1920
  • , "Method and Apparatus for Submarine Signaling" – 22 November, 1921
  • , "Method and Apparatus for Inspecting Material" – 25 April, 1922
  • , "Method and Apparatus for Submarine Signaling" – 9 May, 1922
  • , "Method and Apparatus for Detecting, Measuring, and Utilizing Low Frequency Impulses" – 19 September, 1922
  • , "Acoustic Method and Apparatus" – 1 May, 1923
  • , "Directional Receiving of Submarine Signals" – 30 October, 1923
  • , "Method for Eliminating Undesired Impulses" – 6 November, 1923
  • , "Eliminating Disturbing Energy" – 21 April, 1925
  • , "Means for Eliminating Disturbing Noises" – 28 July, 1925
  • , "Method and Apparatus for Generating Electrical Oscillations" – 8 September, 1925
  • , "Apparatus for Directive Signaling" – 10 November, 1925
  • , "Infusor" (for making tea) – March, 1926
  • , "Method and Apparatus for Coordinating Radio and Phonograph Reproductions" – 1 February, 1927
  • , "Method and Apparatus for the Transmission of Energy by High Frequency Impulses" – 8 February, 1927
  • , "Method and Apparatus for Coordinating Radio and Phonograph Reproductions" – 21 June, 1932
  • , "Means for Parking Cars" – 11 October, 1932
  • , "Means for Modulating Electrical Energy by Light Impulses" – 28 February, 1933
  • , "Rotary Brush" – 14 March, 1933
  • , "Method and Apparatus for Sound Transmission" – 3 July, 1934
  • , "Height Indicator" – 19 February, 1935
  • , "Television System" – 3 November, 1936
  • , "Television Apparatus" – 3 November, 1936

Reissued

  • "Receiver for Electromagnetic Waves" – duplicate of 727,331 reissued May, 1903
  • "Wireless Telegraphy" – duplicate of 706,737 reissued 10 November, 1903
  • "Wireless Telegraphy" – duplicate of 706,737 reissued 10 November, 1903
  • "Acoustic Method and Apparatus" – duplicate of 1,453,316 reissued 10 29 June, 1926

See also

References

Citations

General information

  • Hugh G. J. Aitken, The Continuous Wave: Technology and American Radio, 1900-1932. Princeton University Press. Princeton, New Jersey. 1985.
  • Susan J. Douglas, Inventing American Broadcasting, 1899-1922. The Johns Hopkins University Press. Baltimore, Maryland. 1987.
  • Orrin E. Dunlap, Jr., Radio's 100 Men of Science, Reginald Aubrey Fessenden entry, p. 137-141. Harper & Brothers Publishers. New York. 1944.
  • Helen M. Fessenden, Fessenden: Builder of Tomorrows. Coward-McCann, Inc. New York. 1940.
  • Reginald A. Fessenden, "The Inventions of Reginald A. Fessenden". Radio News, 11 part series beginning with the January, 1925 issue.
  • Reginald A. Fessenden, "Wireless Telephony," Transactions of the American Institute of Electrical Engineers, XXXVII (1908): 553-629.
  • Gary L. Frost, "Inventing Schemes and Strategies: The Making and Selling of the Fessenden Oscillator," Technology and Culture 42, no. 3 (July 2001): 462-488.
  • S. M. Kinter, "Pittsburgh's Contributions to Radio," Proceedings of the Institute of Radio Engineers, (December, 1932): 1849-1862.
  • David W. Kraeuter, "The U. S. Patents of Reginald A. Fessenden". Pittsburgh Antique Radio Society, Inc., Washington Pennsylvania. 1990. OCLC record 20785626.
  • William M. McBride, "Strategic Determinism in Technology Selection: The Electric Battleship and U.S. Naval-Industrial Relations," Technology and Culture 33, no. 2 (April 1992): 248-277.
  • Ormond Raby, Radio's First Voice, Macmillan Company of Canada Limited, 1970

External links

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