Basic Qualification · B-007 Radio wave propagation · B-007-001-010
Reception of high frequency (HF) radio waves beyond 4000 km is generally made possible by:
- A scattered wave
- B space wave
- C ionospheric wave
- D ground wave
Correct answer: C — ionospheric wave. From the official ISED question bank, verified word for word.
Why
High frequency radio waves travel thousands of kilometres by bouncing off the ionosphere, a charged layer high in the atmosphere that acts like a mirror for these signals. 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.