How does increasing the height of an antenna affect the line-of-sight range at VHF/UHF frequencies?

• A. It reduces line-of-sight range due to taller structures
• B. It increases line-of-sight distance, improving coverage
• C. It has no effect on line-of-sight range
• D. It only affects ground reflections

Answer: (B)

Raising antenna height increases the line-of-sight range because VHF/UHF signals travel mostly in straight lines and the Earth’s curvature limits how far the signal can reach. The higher the antenna, the farther the horizon for that station, so the path clears more terrain and obstacles. Practically, the horizon distance scales roughly with the square root of the height, and the total line-of-sight range is roughly the sum of the horizons from both transmitter and receiver. So increasing height directly improves coverage. The other statements don’t fit: height doesn’t reduce range, and the effect isn’t limited to ground reflections.