What type of radio wave propagation occurs when waves are reflected off the ionosphere?

The type of radio wave propagation that occurs when waves are reflected off the ionosphere is known as sky-wave propagation. This phenomenon is critical for long-distance radio communication because it allows radio waves to travel beyond the horizon by bouncing off the ionosphere, a layer of the Earth’s atmosphere that is ionized by solar and cosmic radiation.

When radio waves are transmitted at certain frequencies, particularly high-frequency (HF) bands, they can penetrate the ionosphere and be refracted back to Earth, allowing them to reach distant stations that may be beyond the line of sight. This capability enables effective communication over vast distances, especially during conditions that enhance the ionosphere, such as during the daytime or during sunspot activities.

Understanding this type of propagation is essential for amateur radio operators, especially when planning communications for specific distances and under varying atmospheric conditions.