File:Antenna tuning coil - station WOR.jpg
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Summary
| Description |
English: An antenna tuning inductor on the output stage of the transmitter of AM radio station WOR (AM) in New York City in 1935, which broadcast on 710 kHz at a power of 50 kW. From an advertisement in an electronics magazine. It shows typical construction used in high Q high power radio frequency coils. Since radio frequency currents flow on the surface of conductors due to skin effect, to reduce resistance the coil is made of large surface area copper tubing. To reduce proximity effect losses the windings consist of a single layer, with the turns spaced apart. To reduce dielectric losses the coil is suspended in air, supported by thin ceramic insulator strips. |
| Date | |
| Source | Retrieved November 6, 2015 from Electronics magazine, McGraw-Hill Publishing Co., New York, Vol. 8, No. 9, September 1935, p. 45 on http://www.americanradiohistory.com |
| Author | Unknown author |
| Permission (Reusing this file) |
This image is from an advertisement without a copyright notice published in a 1935 US magazine. In the United States, advertisements published in collective works (magazines and newspapers) are not covered by the copyright notice for the entire collective work. (See U.S. Copyright Office Circular 3, "Copyright Notice", page 3, "Contributions to Collective Works".) Since the advertisement was published before 1978 without a copyright notice, it falls into the public domain. |
Licensing
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This work is in the public domain in the United States because it was published in the United States between 1929 and 1977, inclusive, without a copyright notice. For further explanation, see Commons:Hirtle chart as well as a detailed definition of "publication" for public art. Note that it may still be copyrighted in jurisdictions that do not apply the rule of the shorter term for US works (depending on the date of the author's death), such as Canada (50 p.m.a.), Mainland China (50 p.m.a., not Hong Kong or Macao), Germany (70 p.m.a.), Mexico (100 p.m.a.), Switzerland (70 p.m.a.), and other countries with individual treaties.
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| Date/Time | Thumbnail | Dimensions | User | Comment | |
|---|---|---|---|---|---|
| current | 07:36, 14 July 2016 | | 277 × 415 (27 KB) | Chetvorno | User created page with UploadWizard |
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