General exam question G3A04
Subelement G3, RADIO WAVE PROPAGATION· Group G3A
Which of the following are the least reliable bands for long-distance communications during periods of low solar activity?
- A.80 meters and 160 meters
- B.60 meters and 40 meters
- C.30 meters and 20 meters
- D.15 meters, 12 meters, and 10 meters (correct answer)
Why15 meters, 12 meters, and 10 meters are the least reliable bands for long-distance communication during periods of low solar activity. 15, 12, and 10 meters need the highest MUF of any HF amateur band to open at all, so when solar activity (and MUF) is low, they're the first bands to go quiet and the least reliable for long-distance work, answer D. The lower bands in A, B, and C need much less ionization to stay open and remain comparatively reliable even during a solar minimum.
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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