Which statement about calibrating an ADF antenna installation is true?

Which statement about calibrating an ADF antenna installation is true?

• A. The transmitter power supply needs calibration
• B. The grounding strap needs calibration
• C. The sensing loop antenna needs calibration
• D. The receiver's display needs calibration

Answer: (C)

Calibrating an ADF antenna installation focuses on the directional pattern produced by the sensing loop antenna. The loop creates the directional characteristics used to derive bearing to the NDB, and its alignment and pattern can be distorted by installation geometry, nearby metal, and coupling with the sense antenna. By calibrating the loop (and its relationship to the sense antenna), the indicated bearing is adjusted to match the true bearing to the station, ensuring accurate navigation. The other items aren’t involved in this directional calibration: the transmitter power supply isn’t adjusted for bearing accuracy, the grounding strap is a safety/earth connection, and the receiver’s display generally reflects the receiver electronics rather than the antenna pattern calibration.

Calibrating an ADF antenna installation focuses on the directional pattern produced by the sensing loop antenna. The loop creates the directional characteristics used to derive bearing to the NDB, and its alignment and pattern can be distorted by installation geometry, nearby metal, and coupling with the sense antenna. By calibrating the loop (and its relationship to the sense antenna), the indicated bearing is adjusted to match the true bearing to the station, ensuring accurate navigation. The other items aren’t involved in this directional calibration: the transmitter power supply isn’t adjusted for bearing accuracy, the grounding strap is a safety/earth connection, and the receiver’s display generally reflects the receiver electronics rather than the antenna pattern calibration.