Reflections from an Exponential Atmosphere
01 November 1963
Several conflicting hypotheses have been proposed over the years in an attempt to explain the transhorizon radio field intensities, which in some cases are hundreds of decibels stronger than predicted by smooth earth diffraction theory. 1 ' 6 The rapid fading ordinarily associated with this type of transmission led naturally to the concept of many scattered components with random phase angles. In order to account for the average field intensity, frequency dependence and other characteristics, the scatter hypotheses must make a number of more or less arbitrary assumptions regarding the number, size and distribution of the irregularities and whether the scatterers are spherical "blobs" or flat "pancakes." The scatter concept is a statistical framework that can be adjusted by arbitrary parameters to fit almost any consistent experimental data and, in fact, the values of the parameters have been changed significantly when the need to accommodate unexpected experimental results has arisen. On the other hand, Snell's law of reflection indicates that reflections must occur from the gradual decrease in dielectric permittivity with height. This concept focuses attention on the average received power but, 2849