AN/ARA-50 Automatic Direction Finding System

The AN/ARA-50 is an automatic direction-finding (ADF) and range-finding (TACAN) system for homing on UHF signals.

The system is powered by the primary bus, operates within the frequency range of the AN/ARC-34 command radio receiver, and is controlled through the function switch on the AN/ARC-34 control panel.

The system automatically indicates bearing of UHF signals, allowing the use of these frequencies for homing and rendezvous, including:

  • Selected ground stations
  • UHF radio-equipped aircraft
  • Other UHF radio-equipped sources

The AN/ARA-5O system can be used with the AN/ARN-72 TACAN system to indicate range of the UHF signals emanating from a preselected aircraft.

A flush-type antenna is installed in the lower surface of the fuselage centerline recieves UHF signals for ADF bearings.

Note

When the AN/ARC-34 function switch is set to the ADF position, a changeover relay in the system disconnects the AN/ARN-6 radio compass signal that is sent to the radio magnetic indicator, and connects a directional signal from the AN/ARA-50 ADF system instead. Relative bearing is indicated by the No. 1 (ADF bearing) pointer on the indicator. Range indication is shown on the AN/ARN-72 TACAN range indicator.

Normal Operation

  1. With the command radio on and warmed up, select a common frequency with the ground station or aircraft to be homed on.
  2. Turn the AN/ARC-34 function switch to ADF, and the AN/ARN-72 TACAN function switch to A/A.
  3. The ADF bearing pointer moves in response to the UHF signal to indicate the bearing, and the TACAN range indicator indicates range to the ground station or to the aircraft.

Note

For normal UHF communication, the function switch should be returned to MAIN or BOTH. However, transmission is possible when the switch is at ADF.