Which signal is used to activate the ADF system?

Which signal is used to activate the ADF system?

• A. Ground
• B. GPS signal
• C. VHF signal
• D. Aircraft temperature

Answer: (A)

Automatic Direction Finder hinges on a signal from ground-based beacons. Non-directional beacons on the ground transmit a radio signal that the ADF receiver detects to determine the aircraft’s bearing to the station. When you tune to the beacon’s frequency, the ground signal is what the ADF uses to establish direction, so the source of activation is the ground signal from the NDB. GPS signals would feed a GPS nav system, VHF signals are used for other nav aids, and aircraft temperature has no role in activating or guiding the ADF.

Automatic Direction Finder hinges on a signal from ground-based beacons. Non-directional beacons on the ground transmit a radio signal that the ADF receiver detects to determine the aircraft’s bearing to the station. When you tune to the beacon’s frequency, the ground signal is what the ADF uses to establish direction, so the source of activation is the ground signal from the NDB. GPS signals would feed a GPS nav system, VHF signals are used for other nav aids, and aircraft temperature has no role in activating or guiding the ADF.