Radio Line of Sight and Tower Height
Due to Earth's curvature, the radio horizon limits how far a tower can communicate. The standard 4/3 Earth model accounts for atmospheric refraction that bends radio waves slightly beyond the geometric horizon.
d (km) = sqrt(2 * K * R_earth * h) where R_earth = 6371 km
Total distance = d_tower + d_receiver
Total distance = d_tower + d_receiver
For practical installations, the Fresnel zone clearance should also be maintained, requiring additional height beyond the minimum line-of-sight calculation.