🔍 Key Concepts

• ADF (Automatic Direction Finder) operates in the radio medium-frequency (MF) and low-frequency (LF) bands, not in VHF (very high frequency) aeronautical bands • Know that VHF navigation (like VOR and ILS localizer) uses frequencies in the 108–118 MHz range • Distinguish between kHz vs MHz and remember which units are used for NDB/ADF vs VOR/ILS

💭 Think About

• Which of these options look like MF/LF radio frequencies typically used with kHz for Non‑Directional Beacons (NDBs)? • Which options clearly belong to VHF navigation aids (VOR/ILS), usually given in MHz and used for different equipment than ADF? • Look at the unit first (kHz vs MHz), then ask: does ADF home to NDBs (LF/MF) or to VHF nav aids (VOR/ILS)?

✅ Before You Answer

• Identify which answers are in kHz (LF/MF range) vs MHz (VHF range) • Recall that ADF tracks NDBs, which are LF/MF beacons, not VHF VORs/ILS • Eliminate any ranges that are clearly associated with VOR/ILS navigation rather than NDB/ADF