General exam question G3C05
Subelement G3, RADIO WAVE PROPAGATION· Group G3C
Why is long-distance communication on the 40-, 60-, 80-, and 160-meter bands more difficult during the day?
- A.The F region absorbs signals at these frequencies during daylight hours
- B.The F region is unstable during daylight hours
- C.The D region absorbs signals at these frequencies during daylight hours (correct answer)
- D.The E region is unstable during daylight hours
WhyLong-distance communication on the 40, 60, 80, and 160 meter bands is more difficult during the day because the D region absorbs signals at these frequencies during daylight hours. Sunlight ionizes the D region strongly during the day, and that region absorbs a large share of the energy on 40, 60, 80, and 160 meters before it can reach the higher layers that would otherwise refract it back down, which is why long-distance contacts on these bands get much harder in daylight, answer C. It's the D region doing the absorbing, not the F or E regions being unstable.
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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