Reginald Aubrey Fessenden (October 6, 1866 – July 22, 1932) was a Canadian electrical engineer and inventor who received hundreds of patents in fields related to radio and sonar between 1891 and 1936 (seven of them after his death).

[6][7] They married on September 21, 1890, in the United States at Manhattan in New York City,[8] and later had a son, Reginald Kennelly Fessenden, born May 7, 1893, in Lafayette, Allen, Indiana.

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.

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.

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 Chicago World Columbian Exposition.

[12][13] In the late 1890s, reports began to appear about the success Guglielmo Marconi was having in developing a practical system of transmitting and receiving radio signals, then commonly known as "wireless telegraphy".

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 created by Oliver Lodge and Marconi.

[16] As his work progressed, Fessenden also developed the heterodyne principle, which used two closely spaced radio signals to produce an audible tone that made Morse code transmissions much easier to hear.

[17] Fessenden's initial Weather Bureau work took place at Cobb Island, Maryland, located in the Potomac River about 80 kilometers (50 mi) downstream from Washington, D.C. As the experimentation expanded, additional stations were built along the Atlantic Coast in North Carolina and Virginia.

[18] In November 1902, two wealthy Pittsburgh businessmen, Hay Walker Jr. and Thomas H. Given, financed the formation of the National Electric Signaling Company (NESCO) to support Fessenden's research.

[20] In 1904 an attempt was made to link the General Electric plants in Schenectady, New York, and Lynn, Massachusetts, a distance of 185 miles (298 km), however the effort was unsuccessful.

(A detailed review in Engineering magazine blamed the collapse on sub-standard construction, due to "the way in which the joints were made by the man employed for the purpose by the sub-contractors to whom the work was entrusted by the Brown Hoisting Machinery Company" and "The only wonder is that the tower did not fall before.

")[24] In a letter published in the January 19, 1907, issue of Scientific American, Fessenden discounted the effect of the tower collapse, stating that "The working up to the date of the accident was, however, so successful that the directors of the National Electric Signaling Company have decided that it is unnecessary to carry on the experimental developments any further, and specifications are being drawn up for the erection of five stations for doing transatlantic and other cable work, and a commercial permit is being applied for in England.

John Ambrose Fleming, a Marconi associate, was particularly dismissive in his book The Principles of Electric Wave Telegraphy, a detailed review of the state of the art as he saw it that was published in 1906.

[34] For a time Fessenden continued working with more sophisticated high-frequency spark transmitters, including versions that used compressed air, which began to take on some of the characteristics of arc-transmitters patented by Valdemar Poulsen.

")[37] Fessenden's ultimate plan for an audio-capable transmitter was to take a basic electrical alternator, which normally rotated at speeds that produced alternating current of at most a few hundred cycles-per-second (Hz), and greatly increase its rotational speed, in order to create electrical currents of tens-of-thousands of cycles-per-second (kHz), thus producing a steady continuous-wave transmission when connected to an aerial.

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.

[40] A portion of a report produced by Greenleaf W. Pickard of the Telephone Company's Boston office, which includes additional information on some still existing defects, appeared in Ernst Ruhmer's Wireless Telephony in Theory and Practice.

In this account, Fessenden reported that on the evening of December 24, 1906 (Christmas Eve), he had made the first of two radio broadcasts of music and entertainment to a general audience, using the alternator-transmitter at Brant Rock.

Fessenden remembered producing a short program that included a phonograph record of Ombra mai fu (Largo) by George Frideric Handel, followed by Fessenden playing Adolphe Adam's carol O Holy Night on the violin and singing Adore and be Still by Gounod, and closing with a biblical passage: "Glory to God in the highest and on earth peace to men of good will" (Luke 2:14).

There was general consensus in the centennial discussions that Fessenden had the technical means to make broadcasts, given the widespread reports about the success of the December 21 alternator-transmitter demonstrations.

[citation needed] In the period leading up to the centennial, James E. O'Neal conducted extensive research, but did not find any ships' radio log accounts, or any contemporary literature, to confirm the reported holiday broadcasts.

[49] A follow-up article two years later further reported that a similar attempt to verify the details of the broadcasts had taken place in 1956, which had also failed to uncover any confirmation of Fessenden's statements.

[51] Jack Belrose flatly argued that there was no reason to doubt Fessenden's account, in part because it had not been challenged in the years immediately following publication of the Kintner article.

as, owing to the fact that no wires are needed, simultaneous transmission to many subscribers can be effected as easily as to a few",[32] echoing the words of a handout distributed to the demonstration witnesses, which stated "[Radio] Telephony is admirably adapted for transmitting news, stock quotations, music, race reports, etc.

Though the company immediately began replacing bells and primitive receivers on ships with the new device, it was also the basis for entirely new applications: underwater telegraphy and sonic distance measurement.

However, instead of reviewing his radio work, Fessenden immediately went on a series of tangents, including discussions of which races he believed were the most capable of producing inventions, and the proper approach that government institutions should be taking in order to support inventors.

The next year Philadelphia's Board of Directors of City Trusts awarded Fessenden a John Scott Medal, which included a cash prize of $800, for "his invention of a reception scheme for continuous wave telegraphy and telephony",[69] and recognized him as "One whose labors had been of great benefit."

[70] After settling his lawsuit with RCA, Fessenden purchased a small estate called "Wistowe" (previously the home of Charles Maxwell Allen, the United States Consul, who had hosted Samuel Clemens there), in Hamilton Parish, near to Flatts Village in Bermuda.

It is ironic that among the hundreds of thousands of young radio engineers whose commonplaces of theory rest on what Professor Fessenden fought for bitterly and alone only a handful realize that the battle ever happened...