Radio Horizon Calculator

In direct-wave propagation, radio waves propagate slightly longer than the visual horizon. The actual range depends on weather conditions. This formula assumes normal condition. Also, terrain and other obstacles between radio stations affect the range. This formula assumes a smooth terrain and no obstacles. Enter the height of both transmit and receive antennas. One of them can be zero if you are on the ground with a handheld antenna. If your antenna is higher you get a longer range. When you click the button next to horizon values, the range is computed. You can also fill in h1 and one of the ranges and click the button next to h2 to compute the required height of antenna to receive (or visually see) a station at a known distance.