The Ionosphere, Skip Distances of Radio Waves, and the Propagation of Microwaves

A detailed description of the ionosphere is given based on the recent measurements of the National Bureau of Standards and the Department of Terrestrial Magnetism of the Carnegie Institution. From the ionosphere data the skip distances of radio waves are calculated for temperature and tropical zones, with the diurnal and seasonal changes. The values agree with the observed values as far as they are known. It is concluded that daylight short-wave communication is controlled by the E region in summer and by the F
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region in winter. Theory indicates that the observed bending of microwaves over the horizon, and hence the successful microray communication to a distance of 200 kilometers, is due to diffraction of the microwaves over the bulge of the earth and to temperature gradients in the lower atmosphere.