Gettysburg Air Force Station
Gettysburg Air Force Station (1956-1968) - A Cold War Air Force Radar Station first established in 1956 near Gettysburg, Potter County, South Dakota. Named Gettysburg Air Force Station after the location. Initially assigned a Permanent ID of M-99, later a Sage ID of Z-99. Abandoned by the Air Force in 1968. The FAA activated the Gettysburg FAA Radar Site in 1971 on a small site surrounding the old FPS-27 radar tower.
Established in 1956 and became operational on 5 Jul 1956 as Gettysburg Air Force Station manned by the 903rd AC&W Squadron. The station initially had both a Ground-Control Intercept (GCI) and early warning missions. 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.
This configuration established the minimum requirements for transition to the SAGE System operation.
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 1959 initially feeding the Grand Forks SAGE Direction Center DC-11. The search radar was upgraded to a FPS-66 and then replaced by a FPS-27 search radar circa 1962.
In 1963 the Grand Forks SAGE Direction Center DC-11 closed and control shifted to the Sioux City SAGE Direction Center DC-22. The Sioux City SAGE Direction Center DC-22 was then selected to close on 18 Sep 1968 and Gettysburg Air Force Station was closed just three months before that.
Gettysburg Air Force Station and the 903rd Radar Squadron (SAGE) were deactivated on 18 Jun 1968. Approximately one acre of land surrounding the vacant FPS-27 tower was set aside for FAA use and the remainder of the land was disposed of by the government.
The Gettysburg FAA Radar Site opened in January 1971 on a one-acre portion of the former Gettysburg Air Force Station. The FPS-27 had been removed from the tower and the FAA emplaced a [[FPS-67|FPS-67B] search radar and radome. A FYQ-47 Common Digitizer was added to transmit the radar data to Air Route Traffic Control Centers (ARTCC) in Minneapolis and Denver. The radar equipment was upgraded circa 2015 to the minimally attended CARSR radar in a system-wide FAA upgrade to eliminate obsolete legacy radar equipment.
The physical plant of the site was divided into the main site, a cantonment area, a housing area and a radio site. 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. Apart from the main site was a small 27 unit housing area for married personnel.
A separate radio site housed the radio equipment for directing aircraft intercepts. Like most early radar stations, Gettysburg originally had a radio transmitter site and a separate radio receiver site used by local controllers for voice direction of fighter interceptors to their targets. With the SAGE System, the SAGE Direction centers had the primary task of directing intercepts and the local radio sites were reconfigured, usually into a single site that was known as the Ground to Air Transmitter Receiver (GATR) site. The GATR site communicated with the interceptors from either the local site or the SAGE direction center via voice commands and/or a digital data link.
Abandoned by the Air Force to private interests except for about one acre used by the Gettysburg FAA Radar Site.