Ground Air Transmit Receive

Ground Air Transmit Receive (GATR) control sites 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 crewed interceptor aircraft. 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 to vector F-106 Delta Dart and other suitably equipped aircraft 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, with initial technical training at Keesler Air Force Base. The sites included the RCA AN/GKA-5 Time Division Data Link (TDDL) equipment, that fed a two-channel AN/FRT-49 Electronic Guidance Signals Transmitting Set, employing Varian klystrons to deliver 20 kilowatts output power (early sites used the 100 watt, single-channel AN/GRT-3 instead. The aircraft receivers were either Hughes AN/ARR-60 or SLI AN/ARR-61 Airborne Radio Receivers of the Hughes MA-1 Fire Control System.

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.