Southworth_demonstrating_waveguide.jpg
Size of this preview:
783 × 599 pixels
.
Other resolutions:
314 × 240 pixels
|
627 × 480 pixels
|
810 × 620 pixels
.
Summary
Description Southworth demonstrating waveguide.jpg |
English:
Demonstration in 1938 of the
waveguide
before the Institute of Radio Engineers by the inventor,
Bell Telephone Laboratory
scientist
George C. Southworth
(left)
. Behind the blackboard
(right)
were several vacuum tube oscillators producing 1.5 GHz (8 inch, 20 cm)
microwaves
of different modes. He demonstrated that they could pass through the 25 ft flexible metal waveguide and be detected by a receiver consisting of a
silicon diode
coupled to an amplifier and galvanometer. He demonstrated further properties of the waves:
|
Date | |
Source | Retrieved March 28, 2015 from "Four inch waves turn science topsy-turvy" in Short Wave and Television magazine, Popular Book Corp., New York, Vol. 8, No. 12, April 1938, p. 669 on http://www.americanradiohistory.com |
Author | Unknown author Unknown author |
Permission
( Reusing this file ) |
This 1938 issue of Short Wave and Television magazine would have the copyright renewed in 1966. Online page scans of the Catalog of Copyright Entries, published by the US Copyright Office can be found here . Search of the Renewals for Periodicals for 1965, 1966, and 1967 show no renewal entries for Short Wave and Television . Therefore the copyright was not renewed and it is in the public domain. |
Licensing
Public domain Public domain false false |
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 ∙ +/− |