A D V E N T U R E S   in   C Y B E R S O U N D

The Canadian-born American physicist and electrical engineer Reginald Aubrey Fessenden, (b. Milton, Quebec, Oct. 6, 1866, d. July 22, 1932), is known for his early work in wireless communication. He began his research at the University of Pittsburgh; after designing a high-frequency alternator, he broadcast (1906) the first program of speech and music ever transmitted by radio.

That same year, he established two-way transatlantic wireless telegraph communication. Fessenden also invented the heterodyne system of radio reception, the sonic depth finder, the radio compass, submarine signaling devices, the smoke cloud (for tank warfare), and the turboelectric drive (for battleships).

Source: The New Grolier Multimedia Encyclopedia

...and a short time ago (this was written in 1927) it was announced that he (Fessenden) was at work perfecting an apparatus with which...

"It will be possible to point a radio camera connected to an aerial at the steps of the Capital in Washington, and by doing so enable every radio subscriber acttually to see senators at debate in Congress. Every gesture will be visible and in addition the speech will be heard by means of the radio telephone. With the experimental instrument already constructed, the size of the picture is limited to 4. ft. x 4 ft. on a screen 12 ft distant or 4 in. x 4 in. on a screen 12 in. distant. The corse-grainness of the image at a distance of 12 in. corresponds to the 50 dot per inch process plate photo."

Fessenden was a Canadian-American radio pioneer who broadcast the first program of music and voice ever transmitted over long distances.

After study at Trinity College School, in Port Hope, Ont., and Bishop's College in Lennoxville, Que., Fessenden went to Bermuda as principal of the Whitney Institute, where he developed an interest in science that led him to resign and go to New York. Working as a tester at the Thomas Edison Machine Works, he met Thomas Edison and in 1887 became chief chemist of the Edison Laboratory at Orange, N.J.

In 1890 he became chief electrician at the Westinghouse works at Pittsfield, Mass., and in 1892 turned to an academicc areer, as professor of electrical engineering first at Purdue University, West Lafayette, Ind., then at theWestern University of Pennsylvania (now the University of Pittsburgh), where he worked on the problem of wireless communication.

In 1900 Fessenden left the university to conduct experiments in wireless telegraphy for the U.S. WeatherBureau, which wanted to adapt radiotelegraphy to weather forecasting.

He then became interested invoice transmission and developed the idea of superimposing electric waves, vibrating at the frequencies of sound waves, upon a constant radio frequency, so as to modulate the amplitude of the radio wave into the shape of the sound wave. (This is the principle of amplitude modulation, or AM.) Fessenden also invented an electrolytic radio detector sensitive enough for use in radiotelephony.

In 1902 Fessenden joined two financiers in organizing the National Electric Signalling Company tomanufacture his inventions. He directed Ernst Alexanderson of the General Electric Company in building a 50,000-hertz alternator that made possible the realization of radiotelephony, and Fessenden at once built a transmitting station at Brant Rock, Mass. On Dec. 24, 1906, wireless operators as far away as Norfolk, Va.,were startled to hear speech and music from Brant Rock through their own receivers.

Ships off the Atlantic coast with Fessenden-designed equipment also received the first radio broadcast. Two musical selections, the reading of a poem, and a short talk apparently constituted the program. That same year, Fessenden established two-way transatlantic wireless telegraphic communication between Brant Rock and Scotland.

Fessenden further contributed in 1902 to the development of radio by demonstrating the heterodyneprinciple of converting high-frequency wireless signals to a lower frequency that is more easily controlled and amplified. This was the forerunner of the superheterodyne principle, which made easy tuning of radio signals possible and was a critical factor for the growth of commercial broadcasting.

He won Scientific American's Gold Medal in 1929 for the fathometer, which could determine the depth of water under a ship's keel. Fessenden eventually held 500 patents.

Source: Bellingham Radio Museum

1906, December 24

Canadian physicist Reginald Aubrey Fessenden (1866-1932) makes the first AM radio broadcast, which carries speech and music, from a transmitting station he has built himself at Brant Rock, Massachusetts. The broadcast begins with Fessenden playing Guonod's 'O,Holy Night' on the violin. This is probably the first American radio programme.

Fessenden works first for Thomas Edison (becoming chief chemist of his research labs) and later for George Westinghouse. Subsequently he becomes a professor at the Western University of Pittsburgh, where he begins his major work on the problems of radio communication.

Until this time all radio communications were in Morse code, using single frequency signals. Fessenden devised a method of making sound waves modulate the amplitude of a transmitted radio-frequency carrier wave. (This is what AM stands for - Amplitude Modulation.) This means that radio can reproduce, transmit and receive sounds of different frequencies - such as speech and music.

Fesseden also invented the heterodyne effect. In this, a received radio wave is combined with a wave of a frequency slightly different from the carrier wave. The intermediate frequency wave that is produced as a result is easier to amplify, and can then be demodulated to generate the original sound wave.

Fessenden held over 500 patents by the time of his death, including ones for a high frequency alternator, a fathometer, a sonic depth finder and submarine signalling devices.

Source: http://www.cequel.co.uk/acclarke/shc.html

Back to the Top | Scientists and Engineers A - F | Quit | eMail: Dr Russell Naughton