Basic Qualification · B-007 Radio wave propagation · B-007-004-007
On the VHF and UHF bands, the polarization of the receiving antenna in relation to the transmitting antenna is very important, yet on HF bands it is relatively unimportant. Why is that so?
- A The refraction in the ionosphere changes the wave's polarization
- B The polarization of ground waves and ionospheric waves continually varies
- C The refraction forces the wave's polarization to vertical
- D The polarization of ionospheric waves varies depending on the entry angle into the refracting region
Correct answer: A — The refraction in the ionosphere changes the wave's polarization. From the official ISED question bank, verified word for word.
Why
When radio waves bounce off the ionosphere to travel long distances on HF bands, the process of refraction twists and scrambles their polarization. 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.