Co operative Supervisor & Environment Supervisor The range of radio wave propagation from a transmitting antenna is limited by the curvature of the Earth. The maximum line-of-sight distance from an antenna of height 'h' above the Earth's surface to the horizon is given by $d = \sqrt{2Rh}$, where R is the radius of the Earth. The area covered is a circle with this radius, $A = \pi d^2$.