RADIO HORIZON RANGE (RHR)

The distance at which a direct radio wave can reach a receiving antenna of given height from a transmitting antenna of given height. Note: The radio horizon range in nautical miles, R , is given by the relation R = 1.23( h t 1/2 + h r 1/2 ), where h t and h r are the heights of the transmitting and receiving antennas in feet. The radio horizon range, R , in nautical miles is also given by the relation R = 2.23( h t 1/2 + h r 1/2 ), where h t and h r are the heights of the transmitting and receiving antennas in meters. The effective Earth radius , 4/3 times the actual Earth radius, is used in deriving the formulae. Second-order differentials are neglected. They are of the order of 0.1%. [ From Weik '89 ]