File:White_Alice_Site,_Tropospheric_Antennas_HAER_AK-21-A-2.jpg
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Summary
DescriptionWhite Alice Site, Tropospheric Antennas HAER AK-21-A-2.jpg |
English: Parabolic antenna used in the White Alice Communication System built around 1958 in Alaska by Western Electric and the US Air Force, which provided telephone communication between isolated communities. It was a tropospheric scatter system; large antennas like this beamed 50 kW signals at about 900 MHz at a low angle into the horizon, where they scattered off the tropopause, with a tiny fraction returning to Earth beyond the horizon. Looking East. The tower at right supports the feed horn for the antenna. The system became obsolete with the advent of communications satellites in the 1960s. |
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Date | |||
Source |
Historic American Engineering Record, Library of Congress, Call Number: HAER AK,20-CORD.V,2-A-2
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Author | Rob Stapleton | ||
Other versions | File:White Alice Site, Tropospheric Antennas HAER AK-21-A-2.tif (TIFF file) |
Licensing
Public domainPublic domainfalsefalse |
This image or media file contains material based on a work of a National Park Service employee, created as part of that person's official duties. As a work of the U.S. federal government, such work is in the public domain in the United States. See the NPS website and NPS copyright policy for more information. |
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Items portrayed in this file
depicts
June 1987
File history
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Date/Time | Thumbnail | Dimensions | User | Comment | |
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current | 17:48, 3 March 2011 | 4,687 × 3,726 (1.47 MB) | Martin H. | full size, cropped | |
16:38, 21 February 2011 | 1,024 × 823 (105 KB) | Centovalli | {{Information |Description={{en|1=billboard antenna showing feeder horn on right, looking East}} |Source=*File:000933pu.tif |Date=2011-02-21 16:38 (UTC) |Author=*File:000933pu.tif: Rob Stapleton *derivative work: ~~~ |Permission= |other_versio |
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Metadata
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Author | Library of Congress |
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Width | 4,972 px |
Height | 4,037 px |
Bits per component | 8 |
Compression scheme | Uncompressed |
Pixel composition | Black and white (Black is 0) |
Orientation | Normal |
Number of components | 1 |
Number of rows per strip | 13 |
Data arrangement | chunky format |
File change date and time | 05:23, 21 October 1998 |