What is the function of the ADF when radios are keyed according to the A-395 Relay Assembly?

What is the function of the ADF when radios are keyed according to the A-395 Relay Assembly?

• A. Increases signal strength of the ADF antenna
• B. Provides dial indication of ADF status
• C. Powers the ADF transmitter
• D. Deselects ADF antennas when radios are keyed

Answer: (D)

The key idea is RF isolation between the transmitter and the navigation receiver. When the radios are keyed, the A-395 Relay Assembly automatically deselects the ADF antennas, removing them from the receive/transmit path. This prevents transmitter RF energy from coupling into the ADF receiver, which could desensitize it or cause interference with bearing readings. The ADF is a receiver-based system and does not require transmitter power or a dial indication from this relay function, so the safe, correct operation is to disconnect the ADF antennas during transmit.

The key idea is RF isolation between the transmitter and the navigation receiver. When the radios are keyed, the A-395 Relay Assembly automatically deselects the ADF antennas, removing them from the receive/transmit path. This prevents transmitter RF energy from coupling into the ADF receiver, which could desensitize it or cause interference with bearing readings. The ADF is a receiver-based system and does not require transmitter power or a dial indication from this relay function, so the safe, correct operation is to disconnect the ADF antennas during transmit.