Malmstrom Air Force Base Radar Site

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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.

Malmstrom AFB Radar Site Closeup.
Malmstrom AFB Radar Site After Radar Set Removal.
Malmstrom AFB Radar Site (center) circa 1964-1971.


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.

First Deactivation

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 was again deactivated on 1 Jul 1974.

Malmstrom AFB FAA Radar Site

In 1983 the SAGE System was 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.

Physical Plant

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.

Malmstrom AFS Major Equipment List
Search Radar HF Radar Data Systems Scopes Comm IFF/SIF/Beacon
Unit Designations
  • 801st Aircraft Control & Warning (AC&W) Squadron (1957-1961)
  • 801st Radar Squadron (SAGE) (1961-1969)
  • 801st Radar Squadron (SAGE) (1971-1974)
801st Squadron Assignments
  • By Feb 1956 - Activated at Malmstrom AFB, MT, assigned to 29th AD.
  • 1 Jul 1960 - Transferred to Great Falls ADS. (Malmstrom DC-20)
  • 1 Mar 1961 - Redesignated from AC&W Sq to 301st Radar Sq. (SAGE).
  • 1 Apr 1966 - Transferred to 28th AD. (Malmstrom DC-20)
  • 31 Dec 1969 - Inactivated.
  • 30 Jun 1971 - Activated at Malmstrom AFB, MT. (Malmstrom DC-20)
  • 1 Jul 1974 - Inactivated.

Current Status

Malmstrom AFB Radar Site Today {July 2016). FPS-24 Tower Concrete Pad can be seen at the Center in the background.

Site abandoned on Malmstrom AFB. The on-site roads remain in place along with some foundation elements including the FPS-24 concrete pad.

Location: Great Falls in Cascade County, Montana.

Maps & Images

Lat: 47.50193 Long: -111.20283

  • Multi Maps from ACME
  • Maps from Bing
  • Maps from Google
  • Elevation: 3,472'

GPS Locations:

See Also:



Fortification ID:

  • MT0128 - Malmstrom Air Force Base Radar Site
  • MT0126 - Malmstrom AFB FAA Radar Site

Visited: 12 Aug 2016

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