General exam question G3A02
Subelement G3, RADIO WAVE PROPAGATION· Group G3A
What effect does a sudden ionospheric disturbance have on the daytime ionospheric propagation?
- A.It enhances propagation on all HF frequencies
- B.It disrupts signals on lower frequencies more than those on higher frequencies (correct answer)
- C.It disrupts communications via satellite more than direct communications
- D.None, because only areas on the night side of the Earth are affected
WhyA sudden ionospheric disturbance disrupts signals on lower HF frequencies more than those on higher frequencies. A sudden ionospheric disturbance floods the sunlit D region with extra X-ray-driven ionization, and that absorption hits lower HF frequencies much harder than higher ones, so lower-frequency signals suffer more, answer B. It doesn't enhance every HF frequency, and while satellite paths can be affected too, the disturbance isn't specifically worse for satellite links than for direct ground-to-ground HF paths, and it affects the sunlit side of Earth, not just the dark side.
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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