War over Radio Waves: Signals Intelligence By The Radar War: Electronics Intelligence The enemy's air defense system depended heavily on radar signals. Enemy radars detected incoming U.S. aircraft, guided surface-to-air missiles and directed anti-aircraft fire. Air Force RB-66C, RB-47H and RC-135 crews identified enemy radar locations and recorded their signals. This electronics intelligence (ELINT) information was then used to target radar sites, warn friendly forces and develop countermeasures against enemy defenses. Listening in on the Enemy: Communications Intelligence Intercepting enemy radio voice conversations, or COMINT (for communications intelligence), proved to be a rich source of information about the enemy. COMINT aircraft carried sophisticated electronic surveillance equipment and highly-trained technicians and linguists. Antique Airlines: EC-47 Airborne Radio Direction Finding Using airborne radio direction finding (ARDF) equipment, EC-47 crews found enemy ground forces through their radio transmissions. Once the location of a radio signal was "fixed," the information was quickly passed on to friendly troops. EC-47 ARDF fixes were used to target an enemy force for air, ground or artillery attack and to save friendly forces from ambush. EC-47s also carried linguists who listened in on enemy radio voice transmissions (called communications intelligence or COMINT), gathering even greater knowledge about enemy activity. Click here to return to the SEA Reconnaissance Overview.