The Analysis of Observations on Spaced Receivers of the Fading of Radio Signals

The fading of a radio wave once reflected from an irregular ionosphere is discussed in terms of the variable diffraction pattern produced at the ground. It is pointed out that fading may arise either by a drift of the diffraction pattern past a receiver, or by irregular variations in the pattern, or by both mechanisms together It is shown how, from observations at three receiving points, it is possible to deduce the rate at which the pattern is changing and the velocity with which it drifts over the ground This velocity is of interest as it may be related to the wind velocity at ionospheric heights in the atmosphere, but the relation of the diffraction pattern to the irregular ionosphere which produces it is not discussed in detail