The AN/FPS-17 was a ground-based fixed-beam radar system that was installed at three locations worldwide, including Pirinçlik Air Base (formerly Diyarbakir Air Station) in south-eastern Turkey, Laredo, Texas and Shemya Island, Alaska.
This system was deployed to satisfy scientific and technical intelligence collection requirements during the Cold War. The first installation (designated AN/FPS-17, XW-1) at Diyarbakir was originally intended to provide surveillance of the USSR's missile test range at Kapustin Yar south of Stalingrad - especially to detect missile launchings. The data it produced, however, exceeded surveillance requirements, permitting the derivation of missile trajectories, the identification of earth satellite launches, the calculation of a satellite's ephemeris (position and orbit), and the synthesis of booster rocket performance. The success achieved by this fixed-beam radar led to the co-location of a tracking radar (AN/FPS-79), beginning in mid-1964. Together, these radars had the capability for estimating the configuration and dimensions of satellites or missiles and observing the reentry of manned or unmanned vehicles.
A second FPS-17 installation was made at Laredo, Texas, which was used primarily as a research and development site. The final operational installation was made at Shemya Island, Alaska, for missile detection.
Genesis
Experimentation with the detection of missiles by a modified SCR-270 radar in 1948 and 1949 at Holloman Air Force Base, New Mexico along with U.S. experience in the use of high-power components on other radars, created a basis for believing that a megawatt-rated radar could be fabricated for operation over much longer ranges than ever before. The need for intelligence on Soviet missile activity being acute, a formal requirement for such a radar was established, and Rome Air Development Center was given responsibility for engineering the system.
In October 1954 General Electric, which had experience in producing high-power VHF equipment and radars, was awarded a contract for the fabrication, installation, and testing of what was to be at the time the world's largest and most powerful operational radar. The contract stipulated that the equipment was to be in operation at Site IX near Diyarbakir within nine months: by 1 June 1955. Construction began in February, and the scheduled operational date was missed by fifteen minutes.
The original antenna installation was a large D.S. Kennedy parabolic reflector, high by wide, radiating in the frequency range 175 to 215 megahertz. Standard GE high-power television transmitters, modified for pulse operation, were used initially.
Surveillance was carried out by six horizontal beams over the Kapustin Yar area. In 1958 a second antenna, high by long (called the Cinerama antenna), and new 1.2-megawatt transmitters were installed as part of a modification kit which provided three additional horizontal beams, a seven-beam vertical fan, and greater range capability.
The elaborate system included automatic alarm circuitry, range-finding circuitry, and data-processing equipment; it was equipped to make 35 mm photographic recordings of all signals received. A preliminary reduction of data was accomplished on-site, but the final processing was done in the Foreign Technology Division at Wright Patterson Air Force Base.
From 15 June 1955, when the first Soviet missile was detected, to 1 March 1964, 508 incidents (sightings) were reported, 147 of them during the last two years of the period.
Operation
The post-1958 Pirinçlik system had eight separate radar sets or channels, each with its own exciter, transmitter, duplexer, receiver, and data display unit. These eight channels fed electromagnetic energy into sixteen fixed beams formed by the two antennas, each channel, or transmitter-receiver combination, being time-shared between two beams. Pneumatically driven switches operated on a three-second cycle to power each beam alternately for 1.5 seconds. There were antenna feeds for two additional beams which could be made to function with some patchwork in the wiring.
The antenna feeds were positioned to produce in space the beam pattern depicted in the figure. Beams 1 and 18 were those not ordinarily energized. Beams 1 through 7 used the older of the two antennas; 8 through 18 were formed by the newer, "cinerama" antenna, whose width gave them their narrow horizontal dimension.