Which radio/navigation aids might be affected by thunderstorm activity?

Which radio/navigation aids might be affected by thunderstorm activity?

• A. VOR
• B. ADF
• C. ILS
• D. DME

Answer: (B)

Thunderstorms bring a lot of electrical activity and atmospheric noise, and the navigation aid most sensitive to that is the Automatic Direction Finder operating with non-directional beacons in the MF/LF range. The ADF uses a loop antenna and relies on relatively weak, low-frequency signals that are highly susceptible to static, lightning discharges, and changing atmospheric conditions. That makes the bearing readings swing or become unreliable inside or near thunderstorm cells. VOR, ILS, and DME use higher-frequency signals and/or more robust reference systems. They’re less directly affected by the static and rapid atmospheric changes associated with thunderstorms, so they don’t degrade as noticeably as the ADF in such conditions.

Thunderstorms bring a lot of electrical activity and atmospheric noise, and the navigation aid most sensitive to that is the Automatic Direction Finder operating with non-directional beacons in the MF/LF range. The ADF uses a loop antenna and relies on relatively weak, low-frequency signals that are highly susceptible to static, lightning discharges, and changing atmospheric conditions. That makes the bearing readings swing or become unreliable inside or near thunderstorm cells.

VOR, ILS, and DME use higher-frequency signals and/or more robust reference systems. They’re less directly affected by the static and rapid atmospheric changes associated with thunderstorms, so they don’t degrade as noticeably as the ADF in such conditions.