DescriptionFirst radar return from the Moon - Project Diana 1946.jpg
English: Photo of oscilloscope display showing the first reflection of a radar signal from the Moon, achieved on January 10, 1946 by the US Signal CorpsProject Diana. The radar, in Fort Monmouth, New Jersey, USA, was a modified US Army WW2 SCR-271 set producing 1/4 second pulses at a power of 50 kW at 111.5 MHz, driving a "billboard" reflective array antenna consisting of 64 dipoles in front of a screen reflector giving 24 dB gain. The righthand pulse is the transmitted signal, while the smaller lefthand pulse is the return signal. It took the signal 2.4 seconds to make the 477,000 mile round trip journey from the Earth to the Moon and back. The horizontal axis of the oscilloscope trace is time, but it is calibrated in miles; it can be seen that the round trip time is equivalent to a range of 238,000 miles, the distance from the Earth to the Moon.
Photo taken by employee of the US Army Signal Corps. In addition, this 1946 issue of Radio News magazine is in the public domain. It would have had the copyright renewed in 1974. 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 1973, 1974, and 1975 show no renewal entries for Radio News. Therefore the copyright was not renewed.
Licensing
Public domainPublic domainfalsefalse
This file is a work of a U.S. Army soldier or employee, taken or made as part of that person's official duties. As a work of the U.S. federal government, it is in the public domain in the United States.
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.