Question
Why is the radio horizon for VHF and UHF signals more distant than the visual horizon?
Answer Options
- A) Radio signals move somewhat faster than the speed of light
- B) Radio waves are not blocked by dust particles
- C) The atmosphere refracts radio waves slightly
- D) Radio waves are blocked by dust particles
Correct Answer: C
Explanation
The radio horizon (the maximum line-of-sight distance) is always slightly farther than the visual horizon. This is because the Earth’s atmosphere refracts (bends) radio waves slightly downward. This bending effect is caused by the gradual change in the density and temperature of the air near the surface.
This small, constant downward bending allows the radio wave to follow the curvature of the Earth for a greater distance than light waves. For practical purposes, this effect typically extends the line-of-sight range by about 15% beyond what a perfect visual path would be.
This topic was automatically created to facilitate community discussion about this exam question. Feel free to share study tips, memory tricks, or additional explanations!