Jump to content

File:Hogg horn antennas.jpg

Page contents not supported in other languages.
This is a file from the Wikimedia Commons
From Wikipedia, the free encyclopedia

Original file (699 × 951 pixels, file size: 154 KB, MIME type: image/jpeg)

Description
English: Microwave horn antennas on the roof of a telephone switching center near Madison St. and 17th Ave, Capitol Hill, Seattle, Washington state, USA.
This is part of the TD-2 AT&T Long Lines microwave relay system, created in 1955 to relay telephone calls, television shows, and other data from point to point in the US. The system uses C-band frequencies in two bands at 4 and 6 GHz. This type of antenna is called a Hogg or horn-reflector antenna, invented by Albert Beck and Harald Friis in 1941 and developed at Bell Labs in the 1950s. They consist of a vertical flaring metal horn fed with a 2.8 in. circular waveguide, with a reflector mounted in the mouth at a 45° angle, so the beam of microwaves is emitted horizontally (the aperture of these antennas, facing right, is covered by a plastic sheet to keep out rain). The reflector is a segment of a parabolic reflector, so the antenna is equivalent to a parabolic antenna fed off-axis. The advantage of this type of antenna over an ordinary parabolic (dish) antenna is that it has very small sidelobes; that is it picks up very little radiation from directions outside its main beam axis. This allows the same microwave frequencies to be used by several nearby antennas without interfering with each other. These AT&T model KS-15676 L9 antennas have a gain of about 43 dBi and produce a beamwidth (HPBW) of about 1° at 6 GHz. Backlobe sensitivity is -60 to -80 dBi. (From KS-15676 Horn Reflector Antenna Description, Bell System standards, AT&T Also: Bell Labs Record Nov 1955) Microwave links like this use 2 antennas (one transmitting and one receiving) to send a beam of microwaves of a few watts power to a similar station about 30 miles away. Each antenna can carry tens of thousands of telephone calls.
Date (UTC)
Source
Author


This is a retouched picture, which means that it has been digitally altered from its original version. Modifications: Cropped image, brightened to bring out detail. The original can be viewed here: Seattle-Capitol-Hill-Radio-Antennas-3357.jpg: . Modifications made by Chetvorno.

I, the copyright holder of this work, hereby publish it under the following licenses:
w:en:Creative Commons
attribution share alike
This file is licensed under the Creative Commons Attribution-Share Alike 2.5 Generic, 2.0 Generic and 1.0 Generic license.
You are free:
  • to share – to copy, distribute and transmit the work
  • to remix – to adapt the work
Under the following conditions:
  • attribution – You must give appropriate credit, provide a link to the license, and indicate if changes were made. You may do so in any reasonable manner, but not in any way that suggests the licensor endorses you or your use.
  • share alike – If you remix, transform, or build upon the material, you must distribute your contributions under the same or compatible license as the original.
w:en:Creative Commons
attribution share alike 		This file is licensed under the Creative Commons Attribution-Share Alike 3.0 Unported license.
You are free:
  • to share – to copy, distribute and transmit the work
  • to remix – to adapt the work
Under the following conditions:
  • attribution – You must give appropriate credit, provide a link to the license, and indicate if changes were made. You may do so in any reasonable manner, but not in any way that suggests the licensor endorses you or your use.
  • share alike – If you remix, transform, or build upon the material, you must distribute your contributions under the same or compatible license as the original.
This licensing tag was added to this file as part of the GFDL licensing update.
GNU head Permission is granted to copy, distribute and/or modify this document under the terms of the GNU Free Documentation License, Version 1.2 or any later version published by the Free Software Foundation; with no Invariant Sections, no Front-Cover Texts, and no Back-Cover Texts. A copy of the license is included in the section entitled GNU Free Documentation License.
You may select the license of your choice.

Original upload log

This image is a derivative work of the following images:

  • File:Seattle-Capitol-Hill-Radio-Antennas-3357.jpg licensed with Cc-by-sa-2.5,2.0,1.0, Cc-by-sa-3.0-migrated, GFDL
    • 2007-04-21T00:54:38Z Vmenkov 2048x1536 (1169188 Bytes) ==Summary== {{Information |Description={{en|A radio station (?) near Madison St and 17th Ave, Capitol Hill, Seattle}} |Source=Own photo |Date=2007-Mar-10 |Author=[[User:Vmenkov|Vladimir Menkov]] |Permission={{self2|GFDL|cc-b

Uploaded with derivativeFX

Captions

C-band horn antennas

Items portrayed in this file

depicts

horn antenna

inception

21 April 2007

media type

image/jpeg

exposure time

0.00625 second

focal length

17.4 millimetre

File history

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

Date/TimeThumbnailDimensionsUserComment
current22:37, 11 November 2010Thumbnail for version as of 22:37, 11 November 2010699 × 951 (154 KB)Chetvorno{{Information |Description={{en|Antennas on the roof of a microwave relay station near Madison St. and 17th Ave, Capitol Hill, Seattle, Washington state, USA.}} This is part of a system created by AT&T to relay telephone calls and other data from point t

Global file usage

The following other wikis use this file:

Metadata

This file contains additional information, probably added from the digital camera or scanner used to create or digitize it.

If the file has been modified from its original state, some details may not fully reflect the modified file.

Retrieved from "https://en.wikipedia.org/wiki/File:Hogg_horn_antennas.jpg"