Which factor affects the range of radio signal transmission?

The range of radio signal transmission is significantly influenced by antenna height and power output. When the antenna height is increased, the signal can travel farther because it is less likely to be obstructed by buildings, trees, and other terrain features. Heightening the antenna allows for a more direct line of sight, which is crucial for effective radio communications.

Additionally, the power output of the transmitter plays a vital role in determining how far the signal can propagate. Higher power outputs allow the radio waves to reach greater distances, overcoming obstacles and reducing the effects of signal attenuation. This combination of increased antenna height and sufficient power output ensures that signals maintain strength over longer distances, significantly enhancing communication capabilities.

Other factors in the choices, such as the color of the antenna or the specifics of the coaxial cable material, do not directly influence the range in a substantial way, as they may affect performance in minor, specific scenarios rather than overall range. The distance to the nearest repeater can also be beneficial but is contingent on the existing conditions of antennas and power output, making it secondary to the primary factors of height and output power.