The characteristics of downcoming radio waves

In a recent paper Cherry and Martyn, from a study of the fading experienced simultaneously on a loop and vertical aerial, concluded that there was normally present a lateral deviation of the downcoming rays from the vertical plane through emitter and receiver. It is the main object of the present paper to examine this lateral deviation more completely, and to measure its amount. It has been noted by several workers that the measurement of the angle of incidence of downcoming rays by simultaneous observations on loop and aerial leads to results which vary markedly in periods of a few seconds, and are moreover inconsistent with those deduced from the heights of the reflecting regions in the ionosphere. These inconsistencies have been attributed by various authors to (a ) “angle flicker” of the sky wave; (b ) the purely geometrical consequence of lateral deviation of the sky wave; and (c ) the fact that the measurements were made in low latitudes.