A Suggestion of a Connection between Radio Fading and Small Fluctuations in the Earth's Magnetic Field

The state of polarization of a radio wave returned by the reflecting layer is studied as a function of (a) small changes in the intensity of the Earth's magnetic field, (b) small changes in the frequency of the wave, and (c) small changes in the ionization of the atmosphere. It is shown that for the special electron distribution considered appreciable effects on the intensity of the signal are to be expected for fluctuations in the Earth's field of the order of 5 gammas, for changes in the frequency of the order of 1,0000 cycles, and for changes in the ionization of the order of the one part in 5,000. [The number applies to λ = 70 meters.] The dependence of fading on range indicates that there is a certain range of maximum fading which is of the general order of 100 miles.