File:Hanscom arc AM transmitter.jpg
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Summary[edit]
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English: Early experimental arc radiotelephone (AM or voice) transmitter designed by W. W. Hanscom sometime before 1917. This was one of many variations on the arc converter transmitter invented in 1903 by William Duddell and Valdamar Poulsen, the first crude voice transmitters that were used before vacuum tube AM transmitters took over in the 1920s. It generated sinusoidal waves with a 100 VDC electric arc connected to a series LC circuit. The arc, submerged in a container of alcohol (bottom right) has a servo feedback system with a weight and electromagnet that controls the electrode spacing. The carbon microphone (front panel) connected in series with the transmitter's antenna lead, had to handle the full 2.5 A RF output current and so was water-cooled. Transmitting on 300 to 2700 m (110 to 1000 kHz), it could be received at distances of 100 - 260 mi (160 - 400 km).
Alterations to image: sharpened resolution slightly using GIMP |
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| Source | Downloaded 7 October 2013 from [Alfred N. Goldsmith, "Radio Telephony, Article 5" in The Wireless Age (Wireless Press, Inc., New York), Vol. 4, No. 8, May 1917, p. 562, fig. 53e] on Google Books |
| Author | Alfred North Goldsmith |
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This media file is in the public domain in the United States. This applies to U.S. works where the copyright has expired, often because its first publication occurred prior to January 1, 1929, and if not then due to lack of notice or renewal. See this page for further explanation.
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This image might not be in the public domain outside of the United States; this especially applies in the countries and areas that do not apply the rule of the shorter term for US works, such as Canada, Mainland China (not Hong Kong or Macao), Germany, Mexico, and Switzerland. The creator and year of publication are essential information and must be provided. See Wikipedia:Public domain and Wikipedia:Copyrights for more details.
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| Date/Time | Thumbnail | Dimensions | User | Comment | |
|---|---|---|---|---|---|
| current | 14:19, 8 October 2013 | | 714 × 949 (144 KB) | Chetvorno (talk | contribs) | User created page with UploadWizard |
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