Which ADF limitation is minimized by circuits in the antenna and calibration procedures?

Which ADF limitation is minimized by circuits in the antenna and calibration procedures?

• A. Time Lag
• B. Doppler Shift
• C. Quadrantal Error/Effect
• D. Azimuth Offset

Answer: (C)

Quadrantal error shows up as a quadrant-dependent bearing error in ADF readings, caused by the imperfect directional pattern of the loop antenna and aircraft installation effects. The circuits in the antenna, including balancing and phasing networks, adjust the relative phase and amplitude between the loop and the sense antenna so the directional indication aligns more closely with the true signal direction. Calibration procedures then tune the system to map what is read on the indicator to the actual bearing toward the NDB, reducing residual quadrant-related errors across all directions. Other issues like time delay, Doppler effects, or a fixed azimuth offset aren’t addressed by these antenna balance and calibration steps in the same way, so the focus here is on minimizing the quadrant-dependent bearing error.

Quadrantal error shows up as a quadrant-dependent bearing error in ADF readings, caused by the imperfect directional pattern of the loop antenna and aircraft installation effects. The circuits in the antenna, including balancing and phasing networks, adjust the relative phase and amplitude between the loop and the sense antenna so the directional indication aligns more closely with the true signal direction. Calibration procedures then tune the system to map what is read on the indicator to the actual bearing toward the NDB, reducing residual quadrant-related errors across all directions. Other issues like time delay, Doppler effects, or a fixed azimuth offset aren’t addressed by these antenna balance and calibration steps in the same way, so the focus here is on minimizing the quadrant-dependent bearing error.