Reginald Aubrey Fessenden (October 6, 1866 – July 22, 1932), was a Canadian inventor, born in Quebec, Canada, who performed pioneering experiments in radio, including the use of continuous waves and the early—and possibly the first—radio transmissions of voice and music. In his later career he received hundreds of patents for devices in fields such as high-powered transmitting, sonar, and television.
Fessenden's work is important to geophysicists, because in 1914 he patented the first practical sonar system. A component of that system, the Fessenden oscillator, was later a critical component in all scientific equipment that made high speed timed electronic recording, including early seismic recording systems, such as those created by J. Clarence Karcher and William Haseman. Though we no longer use the vacuum tube technology of Fessenden's day, the concept of using an oscillator as a clock lives on in modern computer technology.
The SEG honors the developers of game changing technologies in exploration geophysics with the Reginald Fessenden Award.
Fessenden invented the technique known as heterodyning, which is the process of mixing two different frequencies to produce a third audible signal that is highly controllable.
Fessenden's worked as an electrical engineer/inventor for numerous employers including Thomas Edison, George Westinghouse, the University of Pittsburg (then called the Western Pennsylvania University), the US Weather Bureau, the National Electric Signaling Company (NESCO), and others.
He held 500 patents spanning fields other than electrical engineering.
On December 23, 1900 at Rockport, Maryland, Fessenden made the first audo radio transmission over the distance of one mile.
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 few days later, two additional demonstrations took place, which may have been 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. It included a phonograph record of Ombra mai fu (Largo) by George Frideric Handel, followed by Fessenden himself playing on the violin Adolphe Adam's carol O Holy Night, singing Gounod's Adore and be Still, and finishing with reading a passage from the Bible: 'Glory to God in the highest and on earth peace to men of good will' (Gospel of Luke 2:14). He petitioned his listeners to write in about the quality of the broadcast as well as their location when they heard it. Surprisingly, his broadcast was heard several hundred miles away; however, accompanying the broadcast was a disturbing noise. This noise was due to irregularities in the spark gap transmitter he used.