Note on Earth Reflection of Ultra Short Radio Waves

In analytical investigations of the resultant pattern of electric intensity about an antenna, for the longer waves, the earth in the vicinity of the antenna has generally been considered as a perfect conductor. At sufficiently high frequencies, the reflected waves may differ considerably in magnitude and phase from perfectly reflected waves. The resultant distribution of electric intensity about an ultra short antenna depends upon the nature of the reflecting surface. Some computations and curves are given for the reflection coefficients and phase angles for various surface conditions, in conjunction with a horizontal ultra short antenna. Theoretical polar diagrams have been computed for various heights of horizontal antenna above the surface.