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Summary
| Description |
One of the first television broadcasting antennas in the United States, installed on the top of the Empire State Building, New York, in 1939, belonging to NBC's experimental television station W2XBS. W2XBS had been broadcasting low-resolution experimental TV transmissions since 1931, but in 1937 went to RCA's new television standard of 441 lines interlaced with a frame rate of 30 Hz, and in 1938 began the first publicly scheduled broadcasts, 5 hours daily, in preparation for the rollout of commercial television at the New York World's Fair in 1939. The new antenna, built by NBC's parent company RCA, had two separate elements to broadcast the separate audio and video signals. The top element is a pair of linked dipoles which radiated the 49.75 MHz audio signal. The bottom is a variety of turnstile antenna that radiated the 46.5 MHz video signal. It consists of two perpendicular dipole elements driven 90° out of phase for omnidirectional coverage. This was a new design at the time, devised to give the antenna a wide bandwidth of 30 MHz. The range of reception was about 50 miles. The antennas incorporated heating elements for deicing. The rod at the top is a lightning rod. Information from "First public schedule gives television impetus", Radio World, May 1938, p. 57 |
| Date | |
| Source | Retrieved March 12, 2014 from Radio World magazine, Hennessy Radio Publications Corp., New York, Vol. 32, No. 1, January 1939, p. 13 on American Radio History website |
| Author | Unknown author |
| Permission (Reusing this file) |
This 1939 issue of Radio World magazine would have the copyright renewed in 1967. Online page scans of the Catalog of Copyright Entries, published by the US Copyright Office can be found here. [1] Search of the Renewals for Periodicals for 1966, 1967 and 1968 show no renewal entries for Radio World. Therefore the magazine's copyright was not renewed and it is in the public domain. |
Licensing
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This work is in the public domain because it was published in the United States between 1929 and 1963, and although there may or may not have been a copyright notice, the copyright was not renewed. For further explanation, see Commons:Hirtle chart and the copyright renewal logs. 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 (70 years p.m.a.), Mainland China (50 years p.m.a., not Hong Kong or Macao), Germany (70 years p.m.a.), Mexico (100 years p.m.a.), Switzerland (70 years 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 | 23:42, 18 March 2014 | | 447 × 852 (42 KB) | Chetvorno | User created page with UploadWizard |
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