Ham Radio General Class Practice Test

Which type of wave propagation is most affected by solar activity?

1. Ground wave propagation

2. Near vertical incidence skywave (NVIS) propagation

3. Atmospheric wave propagation

4. Skywave propagation

The correct answer is: Skywave propagation

Skywave propagation is significantly influenced by solar activity because it relies on the ionosphere, which is a layer of the Earth's atmosphere that is ionized by solar radiation. When solar activity increases, such as during sunspots or solar flares, it enhances the ionization in the ionosphere. This, in turn, improves the reflective characteristics of the ionosphere, allowing radio waves to travel greater distances than they normally would. The increased ionization can also lead to variations in signal quality, affecting communications. The other types of wave propagation are less affected by solar activity. Ground wave propagation primarily occurs along the surface of the Earth and does not depend on the ionosphere. Near vertical incidence skywave (NVIS) propagation is a specific technique that also utilizes the ionosphere but is particularly optimized for shorter distances and low angles. Atmospheric wave propagation concerns waves influenced by weather conditions rather than solar activity. Therefore, skywave propagation is the correct answer, as it is directly impacted by changes in ionospheric conditions caused by solar events.