File:Radio transmitter tank coil.png
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Summary
| Description |
English: An inductor (tank coil) from the tuned circuit of an RF power amplifier of a shortwave radio transmitter, from an advertisement in a 1938 radio magazine. The promotional copy said it was usable up to 27 MHz. This inductor illustrates high Q construction used to reduce resistive losses at high frequencies; it is made of a single layer winding with the turns spaced apart to reduce proximity effect losses, the wire is thick and silver plated to reduce skin effect losses, and the coil is not wound on a coil form but is supported by thin plastic insulators to reduce dielectric losses. It is a plugin unit so the frequency of the transmitter can be changed by exchanging it with a different coil. |
| Date | |
| Source |
Original file: Tuned RF power amplifier.jpg Retrieved March 12, 2014 from Radio News magazine, Ziff-Davis Publishing Co., Chicago, Vol. 20, No. 11, May 1938, p. 31 on American Radio History website This version: Cropped out coil, increased contrast |
| Author |
Original work: Unknown author This version: Chetvorno (talk · contribs) |
| Permission (Reusing this file) |
This image is from an advertisement without a copyright notice published in a 1938 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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File history
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| Date/Time | Thumbnail | Dimensions | User | Comment | |
|---|---|---|---|---|---|
| current | 18:03, 19 March 2022 | | 409 × 384 (118 KB) | Chetvorno | Uploaded a work by {{unknown|author}} from Retrieved March 12, 2014 from [http://www.americanradiohistory.com/Archive-Radio-News/30s/Radio-News-1938-05-R.pdf ''Radio News'' magazine, Ziff-Davis Publishing Co., Chicago, Vol. 20, No. 11, May 1938, p. 31] on [http://www.americanradiohistory.com/ American Radio History] website with UploadWizard |
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