Ham Radio General Class Practice Test

Which phenomenon can occur due to long skip propagation on HF frequencies?

1. Sharp signal distortion

2. Signal enhancement in urban areas

3. Variation of signal strength

4. Interference with VHF communications

The correct answer is: Variation of signal strength

Long skip propagation on HF frequencies is characterized by the reflection of radio waves off the ionosphere, enabling them to travel long distances. This phenomenon leads to variations in signal strength due to several factors, including changes in the ionosphere's density and conditions that can fluctuate throughout the day and season. During such propagation, you might experience periods where a signal becomes stronger or weaker, depending on the path it takes, atmospheric conditions, and the local geography. While sharp signal distortion can occur in some situations, it specifically refers to degradation of the signal quality rather than an inherent property of long skip propagation itself. Signal enhancement in urban areas is not directly related to skip propagation, as urban environments might introduce more noise and interference rather than boost signals. Similarly, while interference with VHF communications can happen, it is not a direct consequence of long skip propagation, which primarily affects HF frequencies.