Basic Qualification · B-007 Radio wave propagation · B-007-006-010
The optimum working frequency provides the best long-range HF communication. Compared with the maximum usable frequency (MUF), it is usually:
- Aslightly lower
- Bdouble the MUF
- Chalf the MUF
- Dslightly higher
Correct answer: A — slightly lower. From the official ISED question bank, verified word for word.
Why
The optimum working frequency is set slightly lower than the maximum usable frequency to ensure the signal reliably reaches the intended distance even if atmospheric conditions change. 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