USAF Air Defense Radar Equipment
Photos, Notes, Misc.

The "Online Radar Museum" is proud to announce that our photo collection now includes several notable "firsts." Among the photos are the very first AN/FPS-24 (Eufaula AFS, AL), the ONLY two AN/FPS-24's covered with a radome (Cottonwood AFS, ID, and Mt. Hebo AFS, OR), the very first AN/FPS-28 (Houma AFS, LA), the very first AN/FPS-35 (Thomasville AFS, AL), the very first AN/FPS-27 (Crystal Springs AFS, MS), and the very first and only AN/FPS-31 (Jug Handle Hill, West Bath, ME). Also, the search radar tower pictured at Highlands AFS, NJ, held the very first AN/FPS-7, and the empty arctic radar tower pictured at Eufaula AFS held the very first AN/FPS-26 height-finder radar. Further, the photo of MacDill AFB, FL, includes the very first AN/FSS-7 SLBM D&W radar, modified from the AN/FPS-26. Thanks go to the many contributors who made this possible.

Radar Designations

During World War II, each service used its own method to designate its electronic radar/tracking systems. For example, Army radars were classified under the initials SCR, which stood for �Signal Corps Radio.� Different designations for similar systems confused manufacturers and complicated electronics procurement. In February 1943, a universal classification system was implemented for all services to follow, ending the confusion. To indicate that an electronic system designation followed the new universal classification, the letters �AN,� for Army-Navy, were placed ahead of a three-letter code. The first letter of the three-letter code denoted the type of platform hosting the electronic device, for example: A=Aircraft; C=Air transportable (letter no longer used starting in the 1950s); F=Fixed permanent land-based; G=General ground use; M=Ground mobile; S=Ship-mounted; T=Ground transportable. The second letter indicated the type of device, for example: P=Radar (pulsed); Q=Sonar; R=Radio. The third letter indicated the function of the radar system device, for example: G=Fire control; R=Receiving (passive detection); S=Search; T=Transmitting. Thus an AN/FPS-20 represented the twentieth design of an Army-Navy �Fixed, Radar, Search� electronic device.

Searching The Skies

Originally, "AN" did stand for "Army-Navy"; later, though, after the Air Force came along, it became just a 'designator' of military equipment.

The table below from Mil Std 196E describes the designators


Radar Bands

Band Freq (MHz) Wavelength (cm)
VHF 30-300 300-100
UHF 300-1000 100-30
L 1000-2000 30-15
S 2000-4000 15-7.5
C 4000-8000 7.5-3.75
X 8000-10,000 3.75-2.5

Type: S-Search, H-Height-Finder, G-Gap Filler, T-Tracker, JSS-Joint Surveillance System

You may click on the Radar System below to see more information.

System Type Band Mfg SAGE Notes
AN/CPS-1 S S/X MIT Rad Lab N MEW, or "microwave early warning radar"; 3000 MHz, range up to 200 miles
AN/CPS-4 H S MIT Rad Lab N Often paired w/ AN/FPS-3 during early '50s at permanent sites
AN/CPS-5 S L Bell Labs, GE N Lashup w/TPS-10 HF
AN/CPS-6,6A,6B S/H S MIT Rad Lab N Combined search & height-finder radar
AN/FPQ-16 PARCS T   Raytheon N Phased-Array Radar, originally part of the Safeguard ABM system
AN/FPS-10 S S MIT Rad Lab N Stripped version of AN/CPS-6B. 13 in the permanent network
AN/FPS-100 S L Bendix Y Modified AN/FPS-20
AN/FPS-107,-107V1,-107V2 S L Westinghouse Y Modification to AN/FPS-7
AN/FPS-108 T L Raytheon N "Cobra Dane"; located on Shemya Island
AN/FPS-115 S UHF Raytheon N PAVE PAWS Missile-Warning Radar, first model, two radar faces; originally installed at Cape Cod AFS, MA, and Beale AFB, CA, and later at Robins AFB, GA, and Eldorado AFS, TX. Upgrades include AN/FPS-120, AN/FPS-123, and AN/FPS-126 models.
AN/FPS-116 H S GE (now Lockheed Mar Y Modernized AN/FPS-6 & AN/FPS-90 for JSS
AN/FPS-117 3D L GE (now Lockheed Mar N 3D radar used at Alaskan sites and on the North Warning System (NWS)
AN/FPS-118 S LF GE (now Lockheed Mar N Over-the-Horizon Backscatter (OTH-B)
AN/FPS-120 S UHF Raytheon N PAVE PAWS Missile-Warning Radar, upgraded from AN/FPS-115 model, two (2) radar faces; presently installed at Thule AB, Greenland (BMEWS Site 1).
AN/FPS-123 S UHF Raytheon N PAVE PAWS Missile-Warning Radar, upgraded from AN/FPS-115 model, two (2) radar faces; presently installed at Cape Cod AFS, MA; Beale AFB, CA; and Clear AFS, AK (BMEWS Site 2).
AN/FPS-124 S S Unisys N Short-Range Radar used in the modern North Warning System (NWS); cylindrical array, electronic scanning
AN/FPS-126 S UHF Raytheon N PAVE PAWS Missile-Warning Radar, upgraded from AN/FPS-115 model, three (3) radar faces; presently installed at RAF Fylingdales Moor, England (BMEWS Site 3).
AN/FPS-129 D X Raytheon N "HAVE STARE"; deployed in northern Norway to detect missile launches
AN/FPS-14 G S Bendix Y Gap-filler radar with magnetron; 65 nmi.
AN/FPS-17 T VHF GE N Missile-tracking radar
AN/FPS-18 G S Bendix Y Gap-filler radar with klystron; 65 nmi.
AN/FPS-19 S L Raytheon Y The Primary Search Radar for DEW-Line sites in Canada and Alaska
AN/FPS-20,20A,20B S L Bendix Y AN/FPS-3 with AN/GPA-27; variants include the AN/FPS-64,65,66,67,68,72,87,91,93,100
AN/FPS-23 S UHF Motorola N AN/FPS-23 radars were continuous-wave (CW) systems that were comprised of geographically-separated AN/FPT-4 Fluttar Transmitters and AN/FPR-2 Fluttar Receivers.
AN/FPS-24 S VHF GE Y Frequency-diverse search radar designed for SAGE. 85-ton antenna.
AN/FPS-26,26A H C AVCO Y Frequency-diverse height-finder radar designed for SAGE. Seven -26s later modified by AVCO to AN/FSS-7 SLBM D&W.
AN/FPS-27,27A,27B S S Westinghouse Y Frequency-diverse search radar designed for SAGE. Search alt. 150K, 220-nmi range
AN/FPS-28 S VHF Raytheon Y Frequency-diverse search radar designed for SAGE. Field tested at Houma AFS, LA
AN/FPS-3,3A S L Bendix Y Predecessor to the AN/FPS-20
AN/FPS-30 S L Bendix Y DEW-Line radar used in Greenland
AN/FPS-31 S VHF MIT Lincoln Labs Y Frequency-diverse search radar designed for SAGE. Antenna 120'x16'; field tested at West Bath, ME.
AN/FPS-35 S VHF Sperry Gyroscope Y Frequency-diverse search radar designed for SAGE. 70-ton antenna.
AN/FPS-3B S L Bendix Y Incorporated AN/GPA-27 increased search alt to 65K
AN/FPS-4 H X RCA N Updated TPS-10
AN/FPS-49 T UHF RCA N BMEWS Tracker, 105 tons on azimuth bearing
AN/FPS-50 S UHF GE N BMEWS Detection Radar, scanned stationary antennae
AN/FPS-6,6A,6B H S GE Y High-power variants include AN/FPS-89 and AN/FPS-90; mobile version is AN/MPS-14
AN/FPS-63 G S Budd Y Frequency-diverse gap-filler radar, similar to AN/FPS-74; neither was ever fielded.
AN/FPS-64,65,66,67,68,72 S L Bendix Y Modified versions of AN/FPS-20
AN/FPS-7,7A,7B,7C,7D S L GE Y Search alt 100K, 270 miles
AN/FPS-74 G S Budd Y Frequency-diverse gap-filler radar, similar to AN/FPS-63; neither was ever fielded.
AN/FPS-8 S L GE Y Variants: AN/GPS-3, AN/MPS-11, AN/FPS-88.
AN/FPS-85 T UHF Bendix N Spacetrack radar at Eglin AFB, FL
AN/FPS-87A S L Bendix Y Based on AN/FPS-20
AN/FPS-88 S L GE Y Updated version of AN/FPS-8
AN/FPS-89 H S GE Y Improved version of AN/FPS-6
AN/FPS-90 H S GE Y Hi-powered version of AN/FPS-6
AN/FPS-91 S L Bendix Y Version of AN/FPS-20
AN/FPS-92 T UHF RCA N Upgraded AN/FPS-49 BMEWS tracker
AN/FPS-93 S L Raytheon Y Modified AN/FPS-20
AN/FRT-80 OTH-F TX D     N Over-the-Horixon Forwardscatter (OTH-F), 440L System, transmitter; used to detect missile launches
AN/FSA-10 DP     Y Television convertor-display unit for the SAGE gap-fillers. This unit used a television camera to superimpose the gap-filler data on the LRR scope. It could display up to six GFAs' radar data.
AN/FSQ-32 DP   IBM Y "Super SAGE" Computer (not fielded)
AN/FSQ-7 DP   IBM Y SAGE Direction-Center Computer
AN/FSQ-76 OTH-F RX D     N Over-the-Horixon Forwardscatter (OTH-F), 440L System, receiver; used to detect missile launches
AN/FSQ-8 DP   IBM Y SAGE Control-Center Computer
AN/FSS-7 S C AVCO Y FPS-26 modified by AVCO to perform SLBM Detection & Warning duties
AN/FST-1 DP     Y Radar Data Processing System used at SAGE gap-filler radar sites. Analog to digital convertor; slowed-down video unit.
AN/FST-2 DP     Y Radar Data Processing System used at SAGE long-range radar sites
AN/FSW-1 DP     Y Remote control unit for gap fillers. There was one unit at the prime LRR, and another at the GFA.
AN/FYQ-156       N Atmospheric Early Warning System, Battle Control System - Fixed (BCS-F) - more info to follow
AN/FYQ-47,49 DP   Burroughs Y Replacement for AN/FST-2; FYQ-49 was a FYQ-47 without height racks (used at FAA data-tie radar sites)
AN/FYQ-93 DP   Hughes N H5118ME-based computer system, replacement for SAGE; used at JSS ROCC's/SOCC's (now SAOC's)
AN/GKA-5 TDDL   RCA Y Time-Division Data Link. Used at the GATR sites for SAGE radar sites and certain Direction Centers (sometimes followed with the AN/FRT-49 Amplifier / Transmitter), and also used at BOMARC "B" model missile launch sites.
AN/GLA-8       Y Signal processor on the FPS-35/24 radars
AN/GPA-98       N ECM Simulator
AN/GPS-3 S L GE Y Variant of the AN/FPS-8
AN/GPS-T2 Simu   RCA N Used a 70 mm film to simulate radar data
AN/GPS-T4 Simu     N Simulated 12 individually controllable (speed, altitude, bank, climb and turn rates plus IFF) radar targets
AN/GRR-24 GATR     Y Ground-air radio equipment (GATR)
AN/GRT-22 GATR     Y Ground-air radio equipment (GATR)
AN/GSQ-235       N ROCC-AWACS Digital Information Link (RADIL)
AN/MPS-11 S L GE N Mobile version of the AN/FPS-8
AN/MPS-14 H S GE Y Mobile version of the AN/FPS-6
AN/MPS-16,-16A,-16B H C Avco N The AN/MPS-16, -16A and -16B are high-power, long-range, mobile height finders. The radar sets are capable of accepting azimuth control from, and furnishing height data to, search radar sets equipeed with either Indicator Group OA-175/FPS-3 or AN/UPA-35. These are normally transported on four M-35 trucks.
AN/MPS-7 S L Bendix N Mobile version of the FPS-3
AN/MPS-8 H X RCA N Mobile version of the AN/FPS-4
AN/TPS-10,10A,FPS-4,TPS-4 H X MIT Rad Lab N Zenith built -10A post-war; dubbed "Little Abner."
AN/TPS-1B,1C S L Bell Telephone Labs N WW-II 120-nmi, 10,000 ft.
AN/TPS-1D S L Bell Telephone Labs N Mobile search radar; "Tippsy 1 Dog"
AN/TPS-43 S     N Tactical/Mobile search radar
AN/TPS-44 S     N Tactical/Mobile search radar
AN/TPS-75 TAC     N Tactical 3D air battle management radar
AN/UPA-35       N Manual Ops PPI scope
AN/UPX-6, -14, -21 IFF/     Y Selective Identification Feature (SIF) / Identification Friend or Foe (IFF); used in conjunction with search radars
ARSR-1 S L Raytheon N FAA search radar, similar to FPS-20
ARSR-2 S L Raytheon N FAA upgrade to ARSR-1
ARSR-3,3D S L Westinghouse N FAA D model had height-finder capability
ARSR-4 S/H   Westinghouse N FAA 3D system began deploying in 1990s
ATCBI-5 SIF     Y FAA version of SIF, for "Air Traffic Control Beacon Interrogator"; also called "secondary radar" by the FAA
SCR-268 S,H VHF Western Electric N SCR-268 was operating in VHF-Band radar for gun laying and searchlight direction. It was the US Army's standard early-war anti-aircraft radar system.
SCR-270 S   Westinghouse N The Pearl Harbor radar
SCR-271 S   Westinghouse N variant of SCR-270
TDX-2000     Sensis N Target Data Extractor - used for preparing FAA radar target data for USAF use, among other things.