21. In 1982, the HF radio interception and Direction finding station at Tangimoana was opened. 22. As frequency surveillance and direction finding became more sophisticated, these devices enjoyed some success. 23. A direction finding receiver was also manned, both for surveillance and search and rescue. 24. Army Airborne Radio Direction Finding ( ARDF ) in South Vietnam was phased out. 25. The control room is fully equipped with charts, radio, direction finding equipment and radar. 26. Walther Schwieger, through wireless intercepts and radio direction finding . 27. Messages were intercepted here and bearings on enemy transmissions were provided using direction finding techniques. 28. Other flights may use an analog beacon and are tracked using radio direction finding techniques. 29. Signals could also be recorded for later direction finding . 30. These antennas are also used for radio direction finding .
