File:Cape Cod Air Station - HAER MA-151-A - 384568pu.jpg

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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	2012年2月4日
来源	Daderot
作者	Historic American Engineering Record (HAER), creator