File:Cape Cod Air Station - HAER MA-151-A - 384568pu.jpg
預覽大小：741 × 600 像素。 其他解析度：297 × 240 像素 | 593 × 480 像素 | 949 × 768 像素 | 1,265 × 1,024 像素 | 2,530 × 2,048 像素 | 5,052 × 4,089 像素。
原始檔案 （5,052 × 4,089 像素，檔案大小：10.22 MB，MIME 類型：image/jpeg）
摘要
| 描述 |
English: Closeup of the antenna elements of the US PAVE PAWS (Phased Array Warning System) ballistic missile defense radar located at Cape Cod Air Station, Technical Facility-Scanner Building & Power Plant, Massachusetts Military Reservation, Sandwich, Barnstable County, Massachusetts, USA. Constructed beginning in 1978, it was one of the first phased array radars. Each of the elements is a crossed dipole antenna. The drive current from the transmitter to each antenna passes through a phase shifter controlled by a computer system. The radio waves (microwaves) from each individual antenna combine in front of the antenna to create a narrow beam in a specific direction. By changing the phase shifts the computer can instantly steer the beam in any direction, scanning it across the sky to detect and track missiles. This large antenna produced a narrow "pencil" beam of microwaves only 2.2° wide
"Significance: The Technical Facility/Scanner Building and Power Plant is the central component of the PAVE PAWS complex and performs all the functions required for the missile detection and tracking mission, including detection, processing, and characterization." This image is part of the Historic American Building Survey (HABS), created by the Library of Congress, and hence is in the public domain. Survey number: HAER MA-151-A. Photographers: Bob Kramer (October 1999) and Neal Collett (January 10, 2000). See: https://www.loc.gov/pictures/item/ma1634/ |
| 日期 | |
| 來源 | Daderot |
| 作者 | Historic American Engineering Record (HAER), creator |
授權條款
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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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| 日期/時間 | 縮圖 | 尺寸 | 使用者 | 備註 | |
|---|---|---|---|---|---|
| 目前 | 2012年2月4日 (六) 21:26 | | 5,052 × 4,089（10.22 MB） | Daderot |
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