Almaden Air Force Station was established in 1954 by Air Defense Command as one of a planned deployment of forty-four Mobile radar stations to support the permanent ADC Radar network in the United States sited around the perimeter of the country.
This deployment was projected to be operational by mid-1952. Funding, constant site changes, construction, and equipment delivery delayed deployment.
Almaden Air Force Station located on the summit of Mount Umunhum in the Santa Cruz Mountains, the station is a few miles south of San Jose, California and sits 3,486 feet (1,063 m) above Almaden Valley.
Great difficulties were encountered in construction at this site. During fiscal year 1957, the Air Defense Command held up construction due to funding shortfalls.
This radar became operational in 1962, and the AN/FPS-20
was removed soon afterward and its concrete foundation was re-purposed as a helipad.
In 1963, an AN/FPS-90 replaced the second AN/FPS-6 height-finder and the original AN/FPS-6 was removed and replaced with an AN/MPS-14 height finder adjacent to the AN/FPS-24 radar tower.
The station operated a Ground-to-Air Transmitter-Receiver (GATR)atop the summit of Mount Umunhum until the completion of the AN/FPS-24 radar in 1962.
The original GATR building was subsequently converted to supply storage and ultimately used as a training room facility.
Almaden Air Force Station was abandoned in 1980 by The United States Air Force
deemed off-limits to the general public.
1986 the 42 acre property was purchased by Midpeninsula Regional Open Space District
The site became part of the Sierra Azul Open Space Preserve
but still off-limits to the public because of environmental hazards
Mid-Peninsula Regional Open Space District
estimated it will take $13.1 million dollars to clean up the site for public use.
2009 Mid-Peninsula Regional Open Space District obtained 3.2 million dollars in federal funding
to abate and clean up the site of all hazardous materials.
2012 Clean up of hazardous materials and redemption completed.
On May 10, 2016, the Santa Clara County Board of Supervisors voted unanimously to list the Almaden Air Force Stations Radar Tower on the County Heritage Resource Inventory, thus giving it official historic status and protection from demolition.