The Basic lessons · Radio wave propagation · B-007-001

How Radio Waves Travel: Ground, Sky, and Line-of-Sight

This lesson explains why your radio works differently on short versus long distances and how the atmosphere shapes your signal. You will learn the three main paths a radio wave takes and which frequencies use each path.

This lesson is free to read; the rest are part of SignalPrep Pro. The subsection's 10 exam questions are free to practise: practise B-007-001.

What this subsection asks

• What type of wave propagation usually occurs between two nearby VHF transceivers?
• What does near vertical incidence sky-wave (NVIS) propagation enable?
• When a signal is returned to Earth by the ionosphere, what is this called?
• On VHF and higher frequencies, why does the radio horizon extend beyond the visible horizon?
• What type of wave is commonly known as sky wave?
• What portion of a radio signal is directly affected by the surface of the Earth?
• What makes radiocommunication out to 200 km possible at lower HF frequencies during the daytime?
• Considering the bands from 160 metres to 6 metres, which band offers the greatest ground-wave propagation distance?
• What type of radio wave follows a path from the transmitter to the ionosphere and back to Earth?
• Reception of high frequency (HF) radio waves beyond 4000 km is generally made possible by: