| Ground Equipment Facility J-33 (Mill Valley Air Force Station until 1980) | |
|---|---|
| Part of 1951-1968:  Air Defense Command1968-1979:  Air Defense, Tactical Air Command | |
| Mount Tamalpais West Peak, 3.1 miles (5.0 km) WNW ofMill Valley | |
 TheFAA sign for the facility | |
| Site information | |
| Type | Air Route Surveillance Radar |
| Owner | Marin Municipal Water District |
| Controlled by | Federal Aviation Administration |
| Location | |
 | |
| Coordinates | 37°55′26″N122°35′49″W / 37.92389°N 122.59694°W /37.92389; -122.59694 (Mill Valley AFS P-38)[1] |
| Site history | |
| Built | 1951 |
| In use | 1951-1980 (USAF) 1980-present (FAA) |
Ground Equipment Facility J-33 is aFederal Aviation Administration (FAA) radar station of theJoint Surveillance System'sWestern Air Defense Sector (WADS) with anAir Route Surveillance Radar (ARSR-4). The facility was previously aUSAFgeneral surveillance radar station during theCold War.
The site is located on West Peak ofMount Tamalpais, inMarin County, California.
TheCold War radar station near Mill Valley was one of twenty-eight stations approved by theUnited States Secretary of Defense on July 21, 1950,[3]: 171 as part of thePermanent System radar network (the Corps of Engineers managed construction for the USAF).[4] Construction began at an upper location[need quotation to verify] of the formerWorld War IIMount Tamalpais Radar Site of theAircraft Warning Service[5] (the World War II information center of the AWC was located attbd for plotting radar tracks in the San Francisco area).
Mount Tamalpais Air Force Station was themilitary installation where the 666th Aircraft Control and Warning Squadron was activated on January 1, 1951.[6][7][8] The squadron "began operating a pair ofAN/CPS-6B radars at this Bay-area site in late 1951".[9][3] TheAir Defense Command Manual Control Center at the station networkedground-controlled interception radars,[10] and on March 10, 1952, the first Multiple Corridor System for identification of traffic arriving from overseas became operational outside San Francisco.[11] Mount Tamalpais AFS was renamed for the nearbyMill Valley community on December 1, 1953.
Mill Valley Air Force Station' received anAN/FPS-8 in 1955 (subsequently converted to anAN/GPS-3), and during 1956 anAN/FPS-4 height-finder radar operated (superseded by anAN/FPS-6 in 1958.) Mill Valley began operating anAN/FPS-7 search radar1 in 1960 at facility built in 1959 by the General Electric company.[12]
DuringSAGE deployment, aBurroughs AN/FST-2 Coordinate Data Transmitting Set (CDTS) was installed at Mill Valley AFS and "in late 1960" began providing digitize radar tracks for telecommunication via microwave to theAir Defense Direction Center (DC-18) atBeale Air Force Base (the squadron was re-designated666th Radar Squadron (SAGE) on 15 January 1961.) By 1961 the 666th addedAN/FPS-6 and AN/FPS-6B height-finder radars, and a detachment of the 666th began operating radars at theMather AFB P-58 radar station which, as with theFort Ord P-38A gap filler annex (AN/FPS-14 at36°40′04″N121°49′05″W / 36.66778°N 121.81806°W /36.66778; -121.81806 (P-38A)), provided radar video to the Mill Valley CDTS foranalog-to-digital conversion.
Mill Valley AFS was the "San Francisco Defense AreaNORAD Control Center from 1961to 1974" after the Army's "40th Artillery BrigadeAir Defense Command Post" was established in September 1961.[13] Initially planned to use a MartinAN/MSG-4command, control, and coordination system (instead deployed to 2 Alaska Nike/Hawk sites),[14]Martin AN/GSG-5 Battery Integration and Radar Display Equipment (BIRDIE) was instead emplaced theProject Nike "Master Direction Center"[13] (SF-90DC).[15] The AADCP operated by the 40th Artillery Brigade from 1959 until June 1971 (13th Air Defense Artillery Group from July 1971 to August 1974) received crosstelling from the Beale DC-18 for coordinating fire from the TBDNike batteries in theSan Francisco Metropolitan Area.
On July 31, 1963, Mill ValleyP-38 was redesignated as NORAD ID Z-38. With the inactivation of theSan Francisco Air Defense Sector at Beale in 1963,[specify] Mill Valley CDTS data was transmitted toAdair AFS, Oregon (DC-13). GATR R-18 was taken over[when?] by the 666th RADS as OL-A. In 1964 anAN/FPS-26A height-finder radar replaced the AN/FPS-6 and the AN/FPS-6B was modified to anAN/FPS-90. In 1966 the AN/FPS-26A was converted to anAN/FSS-7SLBM detection & warning radar operated by the3d Missile Warning Squadron and later as Detachment 314th Missile Warning Squadron on 8 July 1972.
After transfer toAir Defense, Tactical Air Command (ADTAC) on October 1, 1979, the 666th Radar Squadron was inactivated on September 30, 1980 (the SLBM radar deactivated c. 1980).[citation needed] Most Mill Valley AFS property transferred to theNPS (e.g., forMount Tamalpais State Park[16]), and the radar facilities transferred to the FAA (the USAF retained control of the height-finder that was modified[when?] to an AN/FPS-116). In 1995 the FAA operated an AN/FPS-66A search set. In the late 1990s, 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 anARSR-4 in a tower other than a specially designed ARSR-4 tower.
On December 23, 1980, the USAF declaredfull operational capability for the 1st 7Joint Surveillance SystemRegional Operations Control Centers,[17] including the ROCC replacing the Mill Valley NCC. After 1980s turnover to the FAA, in "1995 the FAA operated an AN/FPS-66A search set" at J-33.[3] The FAA currently operates an ARSR-4 radar at the site.
This article incorporatespublic domain material from the Air Force Historical Research Agencyonly pages i...vi are numbered
The 666th Radar Squadron [atMill Valley Z-38] was under the manual control system of operations from 1951 and was designated as a Master Direction Center. ... September [1961], the squadron became host to the 40th Artillery Brigade Air Defense Command Post. The station was then equipped withBattery Integration and Radar Display Equipment (BIRDIE).
