General exam question G3B06
Subelement G3, RADIO WAVE PROPAGATION· Group G3B
G3B06
What usually happens to radio waves with frequencies below the LUF?
- A.They are refracted back to Earth
- B.They pass through the ionosphere
- C.They are attenuated before reaching the destination (correct answer)
- D.They are refracted and trapped in the ionosphere to circle Earth
WhyRadio waves with frequencies below the LUF are usually attenuated before reaching their destination. Frequencies below the LUF get absorbed too heavily, mostly by the D region, to survive the trip and reach their destination, answer C. They aren't simply refracted back to Earth cleanly (that describes frequencies within the usable window), they don't just pass through unaffected, and they aren't ducted around the planet either.
Published 2026-08-28 · Last updated 2026-08-28 · Question text is verbatim from the 2023-2027 NCVEC Element 3 pool (public domain); the explanation above is original writing, see our methodology.
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