Reginald Aubrey Fessenden Biography (1866-1932)



Nationality
American
Ethnicity
Canadian
Gender
Male
Occupation
physicist

It is unfortunate that Reginald Fessenden is not better remembered for his greatest accomplishment, which was eclipsed by the achievements of his contemporaries. Born on October 6, 1866, in Milton, Quebec, Fessenden was the son ofa minister. He chose not to follow in those footsteps because his true calling was in science.

In 1886, Fessenden moved to New York City and started working at the Edison Machine Works. The following year, Thomas Alva Edison recognized Fessenden's talents and promoted him to the position of chief chemist at his laboratory inWest Orange, New Jersey. Fessenden stayed with Edison for only three years.In 1890, he moved to Pittsfield, Massachusetts, where he was chief electrician for Edison's competitor, Westinghouse Electric Corporation. Two years later, he was a professor of engineering at Purdue University, and from 1893 to 1900 he taught at the Western University of Pennsylvania (now University of Pittsburgh) where he held the same post.

During those 14 years Fessenden went through five jobs. This migrant electrician had gained enough experience to set the stage for his greatest accomplishment. While at Western University, he studied some problems with wireless radio communication, which the U. S. Weather Bureau wanted to use in forecasting.

Fessenden invented a liquid barretter detector which gradually replaced the coherer that was used by Guglielmo Marconi. But Fessenden had a more lofty goal: he wanted to send actual voice messages through the air. To this end he patented, in 1901, a high-frequency alternator (a generator that produces alternating current ). This invention produced a continuous radio wave, instead ofthe intermittent spark-generated pulse with which Marconi was experimentingin Morse code transmission. This wave could be modulated to encode the "shape" of a voice or musical sound.

Fessenden was not alone in his attempt to surpass Marconi's achievement. Leede Forest, who would soon invent the "audion" vacuum tube, was busily building wireless systems which put him in competition with Fessenden. But Fessendenwas a step ahead of de Forest.

Fessenden's plan was to limit the signal to one frequency for better reception over long distances, and to provide modulation which would be decoded at the receiver into voice and musical sound. He approached General Electric for help in constructing a more powerful generator. The task went to Charles Steinmetz, the genius who had used mathematics to work out the details of alternating current circuits. Steinmetz designed an alternator that generated currentat 10,000 cycles per second, but it was not good enough for Fessenden.

The job next went to Ernst Alexanderson. He built a large 80-kilohertz generator that generated 50,000 cycles per second, though not without some disagreements with Fessenden, who thought he knew how to do it better. It took threeyears to build this alternator, which was then installed at a transmitter atBrant Rock, Massachusetts. The transmitter had a range of about 100 miles (160 km).

By 1905, Marconi, de Forest and Fessenden were at each others throats, embroiled in patent infringement lawsuits. Fessenden eventually won a suit againstde Forest for using his detector patent.

The next year, Fessenden's system was finally ready, using amplitude modulation (AM) and an ordinary telephone microphone to impress sound on the radio waves produced by his alternator. After a great deal of promotion, on ChristmasEve, 1906, Fessenden broadcast his voice, violin, and recorded music. This transmission, the first radio broadcast in history, was received by the stunned owners of Fessenden radio sets along the Eastern seaboard of the United States and by ships several hundred miles away in the Atlantic Ocean. Later thatyear, he made the first trans-Atlantic voice communication and announced thefirst trans-Atlantic two-way connection between the United States and Scotland.

Fessenden made other improvements to his receiver. In 1912, he blended the incoming signal with a locally produced but slightly different signal, creatinga beat-frequency tone that was audible. This was the first heterodyne circuit which later became a standard part of radio technology.

Although he was an extremely creative engineer, Fessenden lacked the abilities of a businessman. As impressive as his broadcasting device was, it was toomassive and cumbersome to market for permanent use, and de Forest's inventionof the audion in 1906 soon made it obsolete. He had founded the National Electric Signaling Company in 1902 with the help of wealthy financiers, but hisabrasive personality alienated them, and the financial panic of 1907 wiped out his chance to sell the business to AT&T at a great profit.

Deserted by his backers, Fessenden spent more and more of his time in court where he fought infringements of his patents, which were ultimately sold to the Westinghouse Corporation. This period marked the end of the era of independent inventors; afterwards, most technological advances were made under the firm control of corporations. Yet the experiments of "lone wolves " like Fessenden excited the public and encouraged a generation of enthusiastic radio amateurs.

At the time of his death, on July 22, 1932, Fessenden had over 500 patents tohis credit, making him one of America's most prolific inventors. Most of hisinventions were related to radio, such as a radio compass, but some of his other inventions include a sonic fathometer, a signaling device for submarines, and a turboelectric drive for battleships.



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