File:Amateur T antennas.jpg

Amateur_T_antennas.jpg(656 × 488 pixels, file size: 65 KB, MIME type: image/jpeg)

Captions

Captions

Add a one-line explanation of what this file represents

Summary edit

Description
English: An example of a cage T antenna on a private residence in Omaha, Nebraska USA, used as a transmitting antenna for a amateur radio station in 1924. The top antenna, made of a "cage" of six parallel wires held apart with hoop-shaped spreaders with a "cage" feeder hanging down, is the T antenna, a common type used for transmitting on the longwave band. The "cage" construction serves to decrease the ohmic resistance and increase the capacitance to ground, increasing the antenna current and thus the RF power radiated. The lower antenna, consisting of 6 parallel wires resembling a "clothesline" may be a separate T antenna or may be a counterpoise which serves as a ground for the above antenna.

This picture was part of an article on a campaign in Omaha by Nebraska Power Co. to remove unsafe aerials and promote safe aerial construction, after a man was killed working on an antenna. Radio broadcasting had just begun in 1920, and enthusiastic amateur listeners all over the country were constructing elaborate wire antennas like this necessary to bring in stations from distant cities. Often thsy used unsafe techniques such as mounting antennas on utility poles near high voltage power wiring. This antenna was given as an example of a safe one.

Caption: "This aerial shows how a person who is cautious and mindful of life and property can construct an aerial with perfect safety to all concerned. Every wire, with the exception of three, belongs to the aerial system."
Date
Source Retrieved August 2, 2014 from Jack W. Marer, "Dangerous Aerials" in Radio News magazine, Experimenter Publications, Inc., New York, Vol. 6, No. 5, November 1924, p. 670 archived on American Radio History website
Author Jack W. Marer
Permission
(Reusing this file)
This 1924 issue of Radio News magazine would have the copyright renewed in 1952. 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 1951, 1952 and 1953 show no renewal entries for Radio News. Therefore the copyright was not renewed and it is in the public domain.

Licensing edit

Public domain
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.

العربية  Deutsch  English  español  français  galego  italiano  日本語  한국어  македонски  português  português do Brasil  русский  sicilianu  slovenščina  українська  简体中文  繁體中文  +/−

Flag of the United States
Flag of the United States

File history

Click on a date/time to view the file as it appeared at that time.

Date/TimeThumbnailDimensionsUserComment
current16:59, 7 September 2014Thumbnail for version as of 16:59, 7 September 2014656 × 488 (65 KB)Chetvorno (talk | contribs)User created page with UploadWizard

The following page uses this file: