Mill Valley Air Force Station

 (1951-1980) - A Cold War Air Force Radar Station first established as Mount Tamalpais Air Force Station in 1951 near Mount Tamalpais, Marin County, California. Renamed Mill Valley Air Force Station on 1 Dec 1953 after the nearby location. Initially assigned a Permanent ID of P-38, later a Sage ID of Z-38 and a JSS ID of J-33. Abandoned in 1980. The site also housed Nike Missile Site SF-90DC. Now known as Mill Valley FAA Radar Site with an FAA ID of QMV.

History
Established in 1951 and became operational in 1951 as Mount Tamalpais Air Force Station manned by the 666th AC&W Squadron. The station initially had both a Ground-Control Intercept (GCI) and early warning mission. The early warning mission involved tracking and identifying all aircraft entering their airspace while the GCI mission involved guiding Air Force interceptors to any identified enemy aircraft. Controllers at the station vectored fighter aircraft at the correct course and speed to intercept enemy aircraft using voice commands via ground-to-air radio. The station was renamed Mill Valley Air Force Station in 1953.

Initial equipment included two CPS-6B radars. In 1955 the site received an FPS-8 that was later upgraded to a GPS-3. In 1956 an FPS-4 height-finder radar operated here. In 1958 the FPS-4 was replaced with an FPS-6 height-finder.

SAGE System Transition
The FST-2 installation team was on-site between March 1960 and June 1960

SAGE System Operation


The site began operation as a SAGE site in July 1960 initially under the control of Beale SAGE Direction Center DC-18. The search radar was upgraded to an FPS-7C with one FPS-6 height-finder and one FPS-6B height-finder radar installed. This was the baseline configuration as the site began SAGE operation. A FPS-26A height-finder radar replaced the FPS-6 in 1964. The FPS-6B height-finder was upgraded to an FPS-90.

With the closure of Beale SAGE Direction Center DC-18 on 1 Aug 1963 control of Mill Valley AFS switched to the Adair SAGE Direction Center DC-13. DC-13 closed in 1969 and control then switched to the Luke SAGE Direction Center DC-21 where it remained until the radar site closed.

In the early 1970s the FST-2 was replaced with a more up-to-date coordinate data transmitter, the FYQ-47 (Common Digitizer).

In 1966 the FPS-26A was converted to an FSS-7 SLBM detection & warning radar operated by Det 3, 14th Missile Warning Squadron.

Mill Valley Air Defense Command Post SF-90DC
In September 1962, U.S. Army Air Defense Command Post SF-90DC was established to coordinate the NIKE Missle defenses for the San Francisco Area and Travis Air Force Base within the SAGE System. To support the NIKE command post-Mill Valley AFS was initially equipped with the U.S. Army Battery Integration and Radar Display Equipment GSG-5 BIRDIE system, later changed out for the TSQ-51 Missile Mentor system. Using shared radar data, the command post could direct the NIKE missile defenses using target assignments from the SAGE System or, if those were not available, establish targets itself. In March of 1974, with the phase-out of the Nike-Ajax and Nike-Hercules missile sites in the area, the Air Defense Command Post SF-90DC was deactivated.

Period newspaper articles and photos describe the BIRDIE system as contained in an 18' by 7' mobile computer van adjacent to the operations building and show two consoles in the operations room in front of the plotting board.

Gap Filler Radars
Mill Valley AFS was responsible for the maintenance of one remote unattended gap-filler radar site. The Mill Valley AFS gap-filler radar was located at Fort Ord between 1954-1955 as a manual site and was not integrated into the SAGE System.

Closure
On 1 Oct 1979 Mill Valley AFS came under TAC jurisdiction and was subsequently closed as an Air Force Station on 30 Sep 1980 when the FAA assumed operational control of the upper operations site. Now known as Mill Valley FAA Radar Site.

Mill Valley FAA Radar Site


This site became an FAA radar site in 1980 but was not operational until the August 1982 timeframe. The initial FAA equipment included anFPS-66A search radar, an FPS-116 height-finder, an FYQ-47 Common Digitizer, and a GPA-124 IFF/SIF encoder. The search radar remained in operation until it was replaced by an ARSR-4 3D radar between 1996 and 1999. The FPS-116 height-finder was removed circa 1988.

By 1990 the site was equipped with an FPS-66A search radar and a CD-2C Common Digitizer. The Mill Valley CD-2C was scheduled to receive an upgrade kit to implement three level weather data processing in June 1992. With the installation of the ARSR-4 3D radar in the late 1990s, the CD-2 common digitizer was no longer required because the digitization functionality was built into the ARSR-4. The current configuration of the site includes the ARSR-4 radar and an ATCBI-6M Beacon set.

Physical Plant
The physical plant of the site was divided into the main operations site on the top of Mount Tamalpais, a cantonment area, a housing area, and a radio site. The operations main site is separated from the cantonment area by a saddle connecting the peaks. The main site housed the operations buildings, the radar towers, and the backup generators. The cantonment area housed the enlisted barracks, the bachelor officer's quarters, the orderly room, the dining hall, the motor pool, and other support buildings. Recreational facilities in the cantonment area included a theater, a bowling alley, a swimming pool, tennis courts, and various hobby shops.

Apart from the main site but adjacent to the cantonment area was a small nine-unit housing area for married personnel built-in 1960-1961.

A separate Ground to Air Transmitter/Receiver (GATR) radio site located at Beale Air Force Base housed the radio equipment for directing aircraft intercepts.

Current Status
Now Mill Valley FAA Radar Site on Mount Tamalpais, Marin County, California.

See Also:
 * Permanent System Radar Sites
 * SAGE System
 * JSS System
 * NIKE System
 * San Francisco NIKE Sites
 * US Radar Sets
 * Beale SAGE Direction Center DC-18
 * Adair SAGE Direction Center DC-13
 * Luke SAGE Direction Center DC-21

Sources:
 * , page 158.
 * , page 103.


 * , page 83.

Links:
 * Radomes - Mill Valley Air Force Station
 * Wikipedia - Mill Valley Air Force Station
 * TechBastard - Mill Valley Air Force Station
 * Library of Congress - HABS Documentation
 * California Military Museum - Mill Valley Air Force Station