Ernst Alexanderson
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Ernst Frederick Werner Alexanderson (January 25, 1878–May 14, 1975) was a Swedish-American electrical engineer. Born in Uppsala, Sweden, and educated at the Royal Institute of Technology in Stockholm and the Technische Hochschule (Technical University) in Berlin, Germany, he spent his professional life in the US. He emigrated to the U.S. in 1902 and spent much of his life working for the General Electric company. He designed the Alexanderson alternator, a high-frequency generator for longwave transmissions, which made modulated (voice) radio broadcasts practical. The only surviving transmitter in a working state is at the Grimeton radio station outside Varberg, Sweden. It is a prime example of pre-electronic radio technology and was added to UNESCO's World heritage list in 2004.
He had been employed at General Electric for only a short period of time when GE received an order from Canadian-born professor and researcher Reginald Fessenden for an alternator with 1000 times higher frequency than any in existence at that time. In the summer of 1906 Dr. Alexanderson presented a 50 kHz alternator that was installed in Fessenden's radio station in Brant Rock, Massachusetts. By fall its output had been improved to 500 watts and 75 kHz. On Christmas Eve, 1906, Fessenden broadcast the first radio transmission with music and talk, playing the violin and reading the gospel himself. The transmission was heard as far away as the Caribbean Sea.
Dr. Alexanderson was also instrumental in the development of television. The first television broadcast in the United States was to his GE Plot home at 1132 Adams Rd in 1927. Over his lifetime, Dr. Alexanderson received 345 patents, the last awarded in 1973 at age 94. The inventor and engineer remained active to an advanced age, working as a consultant to GE and RCA in the 1950's . He is buried at Vale Cemetery in Schenectady, New York.
In 1983, he was inducted into the National Inventors Hall of Fame.
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[edit] Patents
- U.S. Patent 1008577 – High frequency alternator (100 kHz), filed April, 1909; issued, November, 1911
- U.S. Patent 1723908 – Ignition system, (RFI suppressor), filed June, 1926; issued August, 1929
- U.S. Patent 1775801 – Radio signaling system (directional antenna), filed November 1927, issued September 1930
[edit] See also
Tuned radio frequency receiver
[edit] References
- David E. Fisher and Marshall J. Fisher, Tube, the Invention of Television Counterpoint, Washington D.C. USA, (1996) ISBN 1-887178-17-1
- E.F.W. Alexanderson. General Electric Review, January, 1913
- E.F.W. Alexanderson, "Transatlantic Radio Communication", Trans. AIEE, (1919), pp. 1077-1093
[edit] External links
- Inventor's Hall of Fame citation accessed April 10, 2006
- Biography at IEEE History Center accessed April 10, 2006
- Biography at Oldradio.com accessed April 10, 2006
- Illustrated biography at prof. Eugenii Katz website accessed April 10, 2006
- Fessenden and Marconi – their technologies and transatlantic experiments compared. Accessed April 10, 2006
- Transoceanic Radio Communication in 1920, by E.F.W. Alexanderson accessed April 10, 2006
- "A Historical Review of Continuous Wave Radio Frequency Power Generators" accessed April 10, 2006
