Mount Laguna Air Force Station

Mount Laguna Air Force Station (1952-1981) - A Cold War Air Force Radar Station first established in 1952 on Mount Laguna, San Diego County, California. Named Mount Laguna Air Force Station after the location. Initially assigned a Permanent ID of P-76, later a Sage ID of Z-76 and then a JSS ID of J-30. Abandoned by the Air Force in 1981 and transferred to the FAA. Now known as Mount Laguna FAA Radar Site. Mount Laguna Air Force Station FAA ARSR-4 Radar Mount Laguna Air Force Station Microwave Tower Mount Laguna Air Force Station Site 2014 History Mount Laguna AFS 1979 Established in 1952 and became operational in 1952 as Mount Laguna Air Force Station manned by the 751st 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. Initial equipment included the FPS-3 search radar and a CPS-4 height-finder radar. SAGE System Transition The transition of the manual GCI system to the automated SAGE system began with the installation of the FST-2 coordinate data transmitter and search radar upgrades. The FST-2 equipment digitized the radar returns and transmitted the digital returns to the SAGE direction center. Under the SAGE System, interceptor aircraft were directed to their targets by the direction center computers and controllers, greatly reducing the need for local controllers and equipment at every radar station. The FST-2 was a very large digital system using vacuum tube technology. Over 6900 vacuum tubes were used in each FST-2 requiring 21 air-conditioned cabinets, 40 tons of air conditioning, 43.5 kva of prime power, and usually a large new addition to the operations building. The FST-2B modification added two more cabinets but with newer solid-state (transistor) technology to process coded responses from aircraft transponders. SAGE System Operation The site began operation as a SAGE site in 1961 initially feeding the Norton SAGE Direction Center DC-17. The search radar was upgraded to an FPS-7C with a pair of FPS-6 height-finder radars. One FPS-6 was later upgraded to an FPS-90. With the closure of the Norton SAGE Direction Center DC-17 in 1966, Mount Laguna AFS began to feed data to the Luke SAGE Direction Center DC-21. In 1962 Mount Laguna became a joint-use (FAA/USAF) site feeding radar data to the Palmdale FAA Center. In 1964 the FPS-6 Height finder was replaced by an FPS-26A Height finder which was upgraded in 1966 to an FSS-7 Submarine Launched Ballistic Missile (SLBM) detection radar operated by Detachment 4, 14 Missile Warning Squadron (MWS) from 8 Jul 1972 to 15 Sep 1980. Closure In 1979 Mount Laguna AFS came under TAC jurisdiction and was subsequently closed and abandoned on 30 Sep 1981. The Air Force maintained an Operating Location Alpha Delta (OL-AD) responsible for the height finder operations on the main site until they were deactivated. Gap Filler Radars Mount Laguna AFS was responsible for the maintenance of five remote unattended gap filler radar sites (a sixth never became operational). The unattended gap filler sites were placed in locations where the main search radar lacked coverage. These sites were equipped with short range FPS-14 or FPS-18 search radars and FST-1 Coordinate Data transmitters that sent digitized radar target data to a SAGE direction center and to the main radar site. Both the radar set and the FST-1 were dual channel to increase site up time. Maintenance teams were dispatched for regularly scheduled maintenance or when fault indicators on the FSW-1 remote monitoring equipment suggested the site had problems. The FSW-1 also allowed remote operation of specific functions such as channel changes for the radar and for the FST-1, it also allowed remote operation of the diesel generators at the gap filler site. Mount Laguna AFS Gap Filler Radar Sites (edit list) ADC NORAD Location State Type From To GPS Notes P-76A Z-76A Tecate CA FPS-14, FST-1 1957 1961 32.579444, -116.688889 P-76B Z-76B San Ysidro CA FPS-1?, FST-1 32.561667, -117.035 P-76C Z-76C Tierra del Sol CA FPS-1?, FST-1 32.648056, -116.317222 P-76D Z-76D Coyote Wells CA FPS-14, FST-1 1958 1960 32.690833, -115.889167 P-76F Z-76F Joshua Tree CA FPS-18, FST-1 1960 1961 34.155, -116.202361 BUIC System Mount Laguna AFS became a BUIC I GCI site in 1962 and went operational as a BUIC II site on 1 Apr 1966. It later became a BUIC III site and the unit designation was changed in 1970 from the 751st Radar Squadron (SAGE) to the 751st Air Defense Group (BUIC). The BUIC III system provided a backup for a SAGE direction center and provided the ability to display sector-wide radar data on consoles for local weapons controllers. The system duplicated the functionality of the vacuum tube direction center computers with the more up-to-date GSA-51 computer system and replaced the FST-2 with a more up-to-date coordinate data transmitter, the FYQ-47. As the threat from a Soviet bomber fleet lessened the decision came to mothball the BUIC system in 1974. The 751st Air Defense Group (BUIC) became the 751st Radar Squadron in 1974. Physical Plant The physical plant of the site was divided into an upper main site, an upper GATR radio site, a lower cantonment area and a lower housing area. The main site housed the operations buildings, the radar towers, and the backup generators. The cantonment area housed the four enlisted barracks, the medical/dental clinic/bachelor officer's quarters, the orderly room, the dining hall, a small commissary, motor pool and other support/recreational buildings. Apart from the main site was a small housing area for critical married personnel. A separate upper radio site housed the GATR radio equipment for directing aircraft intercepts. The lower sites were connected by a road system to the upper sites and buses were used to transport personnel at shift change times. A 60kw solar farm was installed in 1975 just below the main site. At the peak level of operations during the BUIC III, years over 500 personnel were assigned to the station. Mount Laguna AFS Major Equipment List Search Radar HF Radar Data Systems FPS-3 FPS-8 FPS-7C ARSR-3 (FAA) ARSR-4 (FAA) CPS-4 FPS-6 FPS-6A FPS-90 FPS-26A FSS-7 FPS-116 FST-2/A/B FYQ-47 GSA-51 GSA-51A Unit Designations 751st Aircraft Control & Warning (AC&W) Squadron (1951-1961) 751st Radar Squadron (SAGE) (1961-1970) 751st Air Defense Group (1970-1974) 751st Radar Squadron (1974-1981) OL AD 751st Air Defense SQ (1981-1981) OL AD 26th Air Defense SQ (1981-1989) Detachment 4, 14 MWS (1972-1980) 751st Assignments 1 Jan 1951 Designated as 751st AC&W Squadron at Port Hueneme, CA 1 Jan 1951 - 6 Feb 1952 Assigned to 544th AC&W Group 1 Feb 1952 - Moved to Mount Laguna Air Force Station, CA 6 Feb 1952 - 1 Oct 1959 Assigned to 27th AD 1 Oct 1959 - 1 Apr 1966 Assigned to LA ADS DC-17 1 May 1961 - Redesignated 751st Radar Squadron (SAGE) 1 Apr 1966 - Assigned to 27th AD DC-21 19 Nov 1969 - Assigned to 26th AD DC-21 1 Mar 1970 Redesignated 751st Air Defense Group 1 Mar 1970 - Assigned to 26th AD DC-21 1 Jan 1974 - Redesignated 751st Radar Squadron 1 Jan 1974 - Assigned to 26th AD DC-21 30 Sep 1981 Deactivated Current Status The upper site is now an FAA ARSR-4 3D radar site known as Mount Laguna FAA Radar Site. Only the ARSR-4 radome & tower remain in operation. The tower base of a single previous radar installation remains repurposed as an antenna platform without a radome. All the other radar towers and radomes have been removed as have been some buildings The lower site with the cantonment area and the housing area has been leveled with nothing remaining. {"selectable":false,"width":"500"} Location: Mount Laguna, San Diego County, California. Zoom out to view the GATR site map point. Maps & Images Lat: 32.87667 Long: -116.415 Multi Maps from ACME Maps from Bing Maps from Google Elevation: 6,106' See Also: SAGE System BUIC System JSS System Permanent System Radar Sites US Radar Sets SLBM Detection Systems Norton SAGE Direction Center DC-17 Luke SAGE Direction Center DC-21 Sources: Cornett, Lloyd H. & Johnson, Mildred W., A Handbook of Aerospace Defense Organization (1946-1980), Office of History ADC, Peterson AFB, Colorado, 31 Dec 1980, 179 pages, Pdf, page 86, 163. Winkler, David F., Searching the Skies: the Legacy of the United States Cold War Defense Radar Program, USAF Hq Air Combat Command, 1997, 192 pages, Pdf, page 104. NORAD/CONAD Historical Summary Jan-Dec 1966, dated 1 May 1967, Command History Division, HQ NORAD/CONAD, Unclassified (originally classified Secret), pdf, pages 28-31, Backup Intercept Control Systems USGS Geographic Names Information System (GNIS) Database Entry: 2512297 Links: Radomes - Mount Laguna Air Force Station Wikipedia - Mount Laguna Air Force Station Radomes - Mt. Laguna AFS Revisited Nov 1987 Article Radomes - Mt. Laguna AFS Common Digitizer March 1973 Article Visited: 7 Nov 2014