Basic Qualification · B-007 Radio wave propagation · B-007-001-007
What makes radiocommunication out to 200 km possible at lower HF frequencies during the daytime?
- ATropospheric ducting
- BSkip wave
- CSpace wave
- DGround wave
Correct answer: D — Ground wave. From the official ISED question bank, verified word for word.
Why
Ground wave allows signals to follow the Earth's surface, hugging the curve to reach distances up to 200 km even when the ionosphere is busy reflecting other frequencies during the day. 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