FCC Exam Question: 3-71K1

What is the frequency range of an aircraft’s Automatic Direction Finding (ADF) equipment?

A. 190 kHz to 1750 kHz.
B. 190 MHz to 1750 MHz.
C. 108.10 MHz to 111.95 MHz.
D. 108.00 MHz to 117.95 MHz.
Correct Answer: A

Explanation: Aircraft Automatic Direction Finding (ADF) equipment operates by tuning into Non-Directional Beacons (NDBs). These NDBs transmit in the Low Frequency (LF) and Medium Frequency (MF) bands. The frequency range of **190 kHz to 1750 kHz** accurately covers the operational spectrum for these beacons, allowing the ADF receiver to determine bearing. Option B uses MHz, indicating much higher VHF/UHF frequencies, which are not used by ADF. Options C and D, specifically 108.00 MHz to 117.95 MHz, define the VHF Omni-directional Range (VOR) and Instrument Landing System (ILS) localizer frequencies. These are separate, distinct VHF navigation systems, not related to ADF operation, which relies on LF/MF transmissions.

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Includes Elements 1, 3, 6, 7R, 8, and 9.