Basic Qualification · B-007 Radio wave propagation · B-007-006-011
During summer daytime, which bands are the most difficult for communications beyond ground wave?
- A 20 metres
- B 160 metres and 80 metres
- C 40 metres
- D 30 metres
Correct answer: B — 160 metres and 80 metres. From the official ISED question bank, verified word for word.
Why
During summer daytime, the lower frequency bands like 160 metres and 80 metres struggle to bounce off the ionosphere because the sun strongly absorbs these signals in the lower D layer. The full explanation — and one for every question — is in Pro.
Practise this section
How signals travel: the ionosphere and its layers, skip, ground wave, sporadic E, and which bands work when.