AN/FPS-20/Helipad

 invisible, historical layer / disappeared object

Helipad concrete removed - November, 2013

Site of an AN/FPS-20 General Surveillance Radar antenna. The antenna was later removed and the site turned into a helipad. The photo of the antenna is to show what it looked like and is not representative of the site at Almaden AFS.

Production of the AN/FPS-20 Surveillance Radar began in 1956. This dual-modulator, fixed station, general surveillance system, developed by RADC became the main surveillance radar for the continental United States. Equipped for dual-channel operations with a klystron transmitter, this system provided long-range surveillance capability. This Bendix-built radar was an AN/FPS-3 search radar with an AN/GPA-27 installed. Designed to operate in the L-band frequencies of 1250 to 1350 MHz, the radar had a range of over 200 miles. By the late 1950s, this radar dominated the US radar defense network, with deployment continuing into the early 1960s. In June 1959 Bendix received a contract to provide private industry's MK-447 [the same system as the military AN/GPA-103 ] and MK-448 [AN/GPA-102 ] antijam packages to the radars. With the addition of these packages, the Air Force redesignated the radars as AN/FPS-66 [AN/GPA-102] and AN/FPS-67 [AN/GPA-103].

[AN/FPS-20: Army Navy/Fixed Radar(pulsed) Search -20 (model number)]

www.globalsecurity.org/wmd/systems/an-fps-20.htm