File:Powerful spark gap transmitter.png
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Summary
DescriptionPowerful spark gap transmitter.png |
English: The tuned circuit of a powerful spark-gap radio transmitter in Australia, during the pioneering days of radio in the second decade of the 20th century. From a 1921 book on radio. The source does not identify the radio station.
This was a wireless telegraphy transmitter, that transmitted information by Morse code, not audio as modern radio stations do. The narrow vertical glass jars in the background are Leyden jar capacitors. The two cylinders suspended from the ceiling are the inductively-coupled transmitting coils (inductors) attached to the antenna (not shown). The six small horizontal segmented cylinders mounted in front are quenched spark gaps. The capacitor bank is charged to a high voltage (as much as 75,000 V), until a spark between the segments of the spark gap discharges the capacitors rapidly through the coil, creating radio frequency oscillating currents, which are radiated by the antenna as radio waves. |
Date | |
Source | Downloaded 2010-03-22 from Bernard John Leggett (1921) Wireless Telegraphy, with special reference to the guenched-spark system, E.P. Dutton, New York, fig.17b, facing p.60 on Google Books |
Author | Unknown authorUnknown author |
Permission (Reusing this file) |
Public domain in USA - published in USA prior to 1923 |
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Licensing
Public domainPublic domainfalsefalse |
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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English: "Quenched" spark gaps consisting of stacks of cylindrical metal electrodes in series, separated by microscopic gaps. This design cools and terminates the spark quickly after the energy is transferred to the antenna, allowing the antenna tuned circuit to oscillate freely.
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English: "Oscillation transformer" consisting of two inductively coupled coils of wire. One is attached to the Leyden jar capacitors and spark gap to make a tuned circuit, which oscillates with radio frequency currents when a spark jumps the gap. The second is attached to the antenna and ground and transfers the radio energy into the antenna.
Items portrayed in this file
depicts
1921
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Date/Time | Dimensions | User | Comment | |
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current | 02:41, 3 May 2021 | 688 × 866 (155 KB) | Materialscientist | FFT |
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Horizontal resolution | 28.35 dpc |
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Vertical resolution | 28.35 dpc |
File change date and time | 09:41, 3 May 2021 |