General exam question G3C11
Subelement G3, RADIO WAVE PROPAGATION· Group G3C
Which ionospheric region is the most absorbent of signals below 10 MHz during daylight hours?
- A.The F2 region
- B.The F1 region
- C.The E region
- D.The D region (correct answer)
WhyThe D region is the most absorbent ionospheric region for signals below 10 MHz during daylight hours. Below 10 MHz during daylight, the D region absorbs signals more heavily than any other ionospheric layer, which is exactly why the lower HF bands struggle in the daytime, answer D. The F2, F1, and E regions sit higher and are involved in refracting signals back to Earth, not in absorbing them the way the D region does.
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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