파일:Horn Antenna-in Holmdel, New Jersey - restoration1.jpg
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This is an image of a place or building that is listed on the National Register of Historic Places in the United States of America. Its reference number is 89002457 (Wikidata). |
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English: The 15 meter Holmdel horn antenna at Bell Telephone Laboratories in Holmdel, New Jersey was built in 1959 for pioneering work in communication satellites for the NASA ECHO I. The antenna was 50 feet in length and the entire structure weighed about 18 tons. It was composed of aluminum with a steel base. It was used to detect radio waves that bounced off Project ECHO balloon satellites. The horn was later modified to work with the Telstar Communication Satellite frequencies as a receiver for broadcast signals from the satellite. In 1964, radio astronomers Robert Wilson and Arno Penzias discovered the cosmic microwave background radiation with it, for which they were awarded the 1978 Nobel prize in physics. In 1990 the horn was dedicated to the National Park Service as a National Historic Landmark.
This type of antenna is called a Hogg or horn-reflector antenna, invented by Albert Beck and Harald Friis in 1941 and further developed by D. C. Hogg at Bell Labs in 1961. It consists of a flaring metal horn with a reflector mounted in the mouth at a 45° angle, so the antenna receives radio waves at a 90° angle to the horn axis. The reflector is a segment of a parabolic reflector, so the antenna is equivalent to a parabolic antenna fed off-axis. This type of antenna has characteristics that make it a good radio telescope: it has very broad bandwidth, the aperture efficiency can be calculated accurately, and the horn shields the antenna from electrical noise coming from angles outside the beam axis, so it picks up little thermal ground noise. |
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Original version at Flickr: NASA on The Commons 이 파일은 다음에 의해 파생됨: Horn Antenna-in Holmdel, New Jersey.jpeg |
| 저자 | NASA, restored by Bammesk |
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| 대상 위치 |  | 이 지역의 다른 사진을 보기: 오픈스트리트맵 |  |
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This image or video was catalogued by NASA Headquarters of the United States National Aeronautics and Space Administration (NASA) under Photo ID: GPN-2003-00013 and Alternate ID: 62-Tels-20. This tag does not indicate the copyright status of the attached work. A normal copyright tag is still required. See Commons:Licensing. Other languages:
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이 파일은 NASA에서 제작하였으므로 퍼블릭 도메인입니다. NASA의 저작권 정책에 따르면 NASA의 자료는 명시하지 않는 이상 저작권의 보호를 받지 않습니다. (Template:PD-USGov, 또는 NASA 저작권 정책 문서, JPL 그림 사용 정책을 참고하세요.) |  |
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| 날짜/시간 | 섬네일 | 크기 | 사용자 | 설명 | |
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| 현재 | 2020년 5월 1일 (금) 02:24 | | 2,793 × 2,197 (1.2 MB) | wikimediacommons>Bammesk | removed halo along the bottom edge of the antenna |
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