Subelement K: K – Aircraft— Topic 71: Automatic Direction Finding Equipment (ADF) & Transponders
Question 3-71K1
Element 3 (GROL)What is the frequency range of an aircraft’s Automatic Direction Finding (ADF) equipment?
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.
Related Questions
3-70K5 Choose the only correct statement about the localizer beam system used by aircraft to find the centerline of a runway during an Instrument Landing System (ILS) approach to an airport. The localizer beam system:3-70K6 On runway approach, an ILS Localizer shows:3-71K2 What is meant by the term “night effect” when using an aircraft’s Automatic Direction Finding (ADF) equipment? Night effect refers to the fact that:3-71K3 What are the transmit and receive frequencies of an aircraft’s mode C transponder operating in the Air Traffic Control RADAR Beacon System (ATCRBS)?3-71K4 In addition to duplicating the functions of a mode C transponder, an aircraft’s mode S transponder can also provide: