Malmstrom Air Force Base Radar Site
Malmstrom Air Force Base Radar Site (1957-1969) - A Cold War Air Force Radar Station first established in 1957 on Malmstrom AFB near Great Falls in Cascade County, Montana. Initially assigned a Permanent ID of SM-147, later a Sage ID of Z-147 and a JSS ID of J-77. Abandoned in 1969.
Established in 1957 and became operational in 1957 as Malmstrom Air Force Base Radar Site manned by the 801st 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-20 search radar and a single FPS-6 height-finder radar. A second FPS-6 height-finder radar was added in 1960 in preparation for SAGE System operation. The SAGE annex was completed and the equipment installed by the first half of 1960.
The site began operating as a joint-use FAA/USAF facility by 1959.
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 on 1 Jul 1960 initially feeding radar data to the nearby Malmstrom SAGE Direction Center DC-20. The search radar was upgraded to an FPS-24 in 1964 and one of the two FPS-6 height-finders was upgraded to a FPS-90.
The 801st Radar Squadron was deactivated on 31 Dec 1969 but the operation of the radar site continued under the FAA, supplemented by USAF personnel including operations and radar maintenance personnel.
The 801st Radar Squadron was reactivated on 30 Jun 1971 and was again assigned at the Malmstrom Air Force Base Radar Site. Under FAA operation the FPS-24 search radar had been replaced by an FPS-65A and an FPS-90 was in place as the only height-finder. The FPS-90 height-finder was later upgraded to a FPS-116. Joint use (FAA/USAF) operation continued until the 801st Radar Squadron again deactivated on 1 Jul 1974.
In 1983 the SAGE System deactivated and the Malmstrom AFB FAA Radar Site joined the JSS System with a JSS ID of J-77 as one of the original members. The operation continued with an FPS-65A search radar and an FPS-116 height-finder until the FPS-116 was removed about 1988.
A FYQ-47 Common Digitizer was probably placed in service by February 1973 when the USAF/FAA FST-2 to FYQ-47 replacement program was completed. By 1990 the site was equipped with an FPS-65A search radar and a CD-2C Common Digitizer. The Malmstrom CD-2 was scheduled to receive an upgrade kit to implement three-level weather data processing in April 1992. Operation of the site continued as Malmstrom AFB FAA Radar Site (J-77) until the Bootlegger Ridge FAA Radar Site (J-77A) became operational on 4 Nov 1997.
Because this site was located on an active Air Force Base many of the cantonment and housing functions were provided/located on the main base. The physical plant of this site was divided into just the main site and a radio site. The main site housed the operations buildings, the radar towers, and the backup generators. A separate Ground to Air Transmitter/Receiver (GATR) radio site housed the radio equipment for directing aircraft intercepts.
Site abandoned on Malmstrom AFB. The on-site roads remain in place along with some foundation elements including the FPS-24 concrete pad.
Visited: 12 Aug 2016