Mt Tamalpais West Peak/Mill Valley Air Force Station

 Cold War 1947-1991, nikemissile, closed / former military, historic ruins, air force station (without runway)

Mt. Tam offers breathtaking views of the entire Bay Area on a clear day. The West Peak is taller than the East Peak and has fewer visitors. There is a large FAA-owned radar antenna (protected by a "golf ball" radome) on this peak.

The 666th AC&W Squadron began operating an AN/CPS-6B radar at this Bay-area site in late 1951. In 1955 the site received an AN/FPS-8 that subsequently was converted to an AN/GPS-3. During 1956 an AN/FPS-4 height-finder radar operated here. In 1958 the AN/FPS-4 was superseded by an AN/FPS-6 set. In late 1960 this site began feeding data into the SAGE system. This site began operating an AN/FPS-7 search radar in 1960. By 1961 the 666th operated this radar along with the AN/FPS-6 and AN/FPS-6B height-finder radars. The US Army shared this radar site during the 1960's for Nike-missile control, designating the site as SF-90DC. In 1964 an AN/FPS-26A height-finder radar was added, replacing the AN/FPS-6. Also in 1964, the AN/FPS-6B was modified to an AN/FPS-90. In 1966 the AN/FPS-26A was removed from SAGE duties when it was converted to an AN/FSS-7 SLBM detection & warning radar. Mill Valley AFS came under TAC jurisdiction in October 1979. During the 1980s, most of the property was turned over to the National Park Service and the FAA. The Air Force retained control of the height-finder radar (modified to an AN/FPS-116) and the SLBM radar, which was deactivated circa 1980. In 1995 the FAA operated an AN/FPS-66A search set. In the late 1990's, the AN/FPS-66A was replaced with an ARSR-4 in the old AN/FPS-26A / AN/FSS-7 tower, the only CONUS site to place an ARSR-4 in a tower other than a specially-designed ARSR-4 tower.

The Mill Valley Air Force Station on Mt. Tamalpais was the location of the AADCP for the 40th Artillery Brigade, which distributed the targets and firing orders to SF-88 and other Bay Area Nike batteries, and for the San Francisco NORAD Control Center. The station was integrated into the SAGE system in January, 1961 and that April, Battery Integration and Radar Display Equipment (BIRDIE) was installed, "to provide a tightly-knit control of Nike defenses, unattainable prior to its development, assuring optimum target engagement in the most efficient and economical manner."

The radio callsigns for Mill Valley AFS were Misfit and Sliphorn.

www.radomes.org/museum/
www.militarymuseum.org/MillValleyAFS.html