Mount Umunhum/Almaden Air Force Station

 park, radar station, closed / former military

Former home of the 682nd Radar Squadron. May of the buildings were demolished October and November, 2013.

Great difficulties were encountered in construction at this site, which was built to keep watch over Northern California's airspace as part of the NORAD defense system. A GATR (Ground Air Transmitter Receiver) was located about a mile away on Mount Thayer.

During fiscal year 1957, the Air Defense Command held up construction due to funding shortfalls. The radars finally came on line with AN/FPS-20 and AN/MPS-14 sets in 1958. A year later, an AN/FPS-6A height-finder radar joined the site. In 1961 the site received an AN/FPS-24 radar, but could test the radar only on a not-to-interfere basis with television transmissions. This radar became operational in 1962, and the AN/FPS-20 was removed soon afterwards. In 1963 an AN/FPS-90 replaced the AN/FPS-6A height-finder. The 682nd AC&W Squadron operated this site. The site came under TAC jurisdiction in 1979, and closed 1 April 1980.

At its peak, Almaden AFS housed about 120 people in eighty four buildings. In 1986, it was acquired by the MROSD (Midpeninsula Regional Open Space District). The base is now a part of the Sierra Azul Open Space Preserve although it is not yet open to the public because of environmental hazards (asbestos and lead-based paint). The MROSD estimates it will take at least US$11 million to clean up the base for public use.

www.openspace.org/mount-umunhum-sierra-azul
www.radomes.org/museum/showsite.php?site=Almaden+AFS%2C...