Basic Qualification · B-007 Radio wave propagation · B-007-006-009
When is propagation on the 80-metre band generally the LEAST effective?
- ADaytime in summer
- BEvening in winter
- CEvening in summer
- DDaytime in winter
Correct answer: A — Daytime in summer. From the official ISED question bank, verified word for word.
Why
During the day, the Sun's ultraviolet light creates a dense layer in the upper atmosphere that absorbs lower frequency signals like those on the 80-metre band. The full explanation — and one for every question — is in Pro.
Practise this section
Radio wave propagation is section B-007 of the Basic exam: How signals travel: the ionosphere and its layers, skip, ground wave, sporadic E, and which bands work when.
Drill B-007 — free, no account