File:First 1000ft radio tower.jpg
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[edit]DescriptionFirst 1000ft radio tower.jpg |
English: Medium wave broadcast antenna mast constructed by Blaw-Knox Co.; image from 1955 Blaw-Knox advertisement in radio magazine. The advertising copy claims this is the first antenna mast over one thousand feet high, but does not name the station or its location. Blaw-Knox was the largest manufacturer of radio masts in the 1930s, and its distinctive diamond-shaped masts were iconic symbols of radio during that formative period. One purpose of the wide diamond shape was to reduce the number of guy wires needed; Blaw-Knox masts needed only one set of guys, attached at its wide "waist", while narrow masts needed several sets at different heights to prevent the mast from buckling. This improved the antenna's electrical design, since guy wires disrupted the antenna's radiation pattern. |
Date | |
Source | Retrieved June 18, 2014 from Tele-Tech and Electronic Industries magazine, Caldwell-Clements Inc., Bristol, Connecticut, Vol. 14, No. 6, June 1955, p. 57 on American Radio History website |
Author | Unknown authorUnknown author |
Permission (Reusing this file) |
This image is from an advertisement for Blaw-Knox Co. without a copyright notice published in a 1955 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. |
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[edit]Public domainPublic domainfalsefalse |
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. العربية ∙ беларуская (тарашкевіца) ∙ čeština ∙ Deutsch ∙ Ελληνικά ∙ English ∙ español ∙ français ∙ Bahasa Indonesia ∙ italiano ∙ 日本語 ∙ 한국어 ∙ македонски ∙ Nederlands ∙ português ∙ русский ∙ sicilianu ∙ slovenščina ∙ ไทย ∙ Tiếng Việt ∙ 中文(简体) ∙ 中文(繁體) ∙ +/− |
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current | 22:49, 27 June 2014 | 362 × 1,539 (58 KB) | Chetvorno (talk | contribs) | User created page with UploadWizard |
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