Extensions to the Kerr diffraction region height-gain factor computation graphs and their analytic approximations

For vertically polarized waves over water using UHF frequencies and low antennas, the height-gain factors computed using the Kerr/Blake approximations may be plus or minus several dB in error, thus leading to propagation loss values which are pessimistically high or optimistically low. In addition, at zero antenna height the predicted propagation loss on either polarization would be infinity, which is known to be incorrect. The author shows how to correct the height-gain function approximations so that they are valid for either polarization and any height down to zero, and gives some examples which illustrate the errors obtained when the uncorrected approximations are used