Radio Horizon Calculator

This page provides a radio horizon calculator. It falls under the converters and calculators section.

The calculator determines the radio horizon distance based on the antenna’s height above the Earth’s surface.

EXAMPLE:

• INPUT: 200 ft
• OUTPUT: 20.08 miles

Radio Horizon Equation

At VHF and higher frequencies, space wave propagation is limited to Line-of-Sight (LOS) distances. Therefore, the radio horizon defines the maximum communication range.

The radio horizon extends approximately 60% farther than the optical horizon. This is due to the bending effect of radio waves in the atmosphere.

The following equation is used in the radio horizon calculator:

Radio Horizon = sqrt(2 * h * Re)

Where:

• h = antenna height
• Re = effective radius of the Earth

As mentioned earlier, the radio horizon is primarily dependent on the antenna height.