File:Marconi Carnarvon transmitter valves.jpg
![File:Marconi Carnarvon transmitter valves.jpg](https://upload.wikimedia.org/wikipedia/commons/thumb/4/48/Marconi_Carnarvon_transmitter_valves.jpg/625px-Marconi_Carnarvon_transmitter_valves.jpg?20131002165233)
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Summary
[edit]DescriptionMarconi Carnarvon transmitter valves.jpg |
English: Triode vacuum tubes (valves) that powered the 40 kHz, 100 kilowatt longwave telegraph transmitter installed in 1921 at Marconi Company's transatlantic wireless station at Carnarvon, Wales, UK. At the time this was the most powerful valve transmitter in the world.
Since the power output of early valves was limited, many were used in parallel. The transmitter used 48 (later increased to 56) 4 kW Marconi MT1 valves, developed by Marconi engineer H. L. Round. The valves were 14 in long, the size of footballs, used a plate voltage of 12,000 V and had a lifetime of around 5000 hours. They are constructed so it is easy to replace the filament when it burns out without damaging the tube. Each had its own grid leak capacitor. Without central excitation, the device was unstable and difficult to adjust compared to modern transmitters. Along with a similar transmitter in Glace Bay, Newfoundland, this transmitter was used for commercial radiotelegraph traffic between the US and UK. In December 1921 it made a historic direct radiotelegraph transmission to Australia, a distance of 12,500 miles, at an input power of 160 kW. |
Date | |
Source | Downloaded 8 November 2009 from Henry Smith Williams 1922 Practical Radio, Funk and Wagnalls Co., New York, p. 295 on Google Books |
Author | The photo is credited to "Radio News" |
Licensing
[edit]Public domainPublic domainfalsefalse |
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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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current | 16:52, 2 October 2013 | ![]() | 992 × 952 (275 KB) | Chetvorno (talk | contribs) | User created page with UploadWizard |
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