Ground_Air_Transmit_Receive
Ground Air Transmit Receive (GATR) control sites[1] were the radio stations of a Burroughs 416L SAGE Defense System of the United States Air Force.
They were deployed to automate ground-controlled interception using manned interceptors. Generally located near or, in some cases, on an Aerospace Defense Command radar station, a GATR site was used for the Ground to Air Data Link Subsystem to communicate command guidance via HF/VHF/UHF voice and TDDL[2] to vector F-106 Delta Dart and other suitably equipped aircraft[3] that had been dispatched by teams in Weapons Direction rooms of SAGE Direction Centers. Maintenance was done by the 304x4 Ground Radio Maintenance career field,[4] with initial technical training at Keesler Air Force Base.[5] The sites included the RCA AN/GKA-5 Time Division Data Link (TDDL) equipment,[6] that fed a two-channel AN/FRT-49 Electronic Guidance Signals Transmitting Set,[7] employing Varian klystrons[8] to deliver 20 kilowatts output power (early sites used the 100 watt, single-channel AN/GRT-3 instead.[9] The aircraft receivers were either Hughes AN/ARR-60 or SLI AN/ARR-61 Airborne Radio Receivers[10] of the Hughes MA-1 Fire Control System.[11]
Most GATR/SAGE sites are now Formerly Used Defense Sites (e.g., the 6-acre (2.4 ha) site supported by Oakdale Air Force Station, Pennsylvania) that were closed by the 1995 Base Realignment and Closure Commission.[12]