On Propagation Phenomena and Disturbances of Reception in Radio Telegraphy

The propagation of electromagnetic waves over the earth's surface is studied, particularly for very long distance transmission, for which it is deduced that short waves are inherently unsuitable. Methods of quantitatively determining the strength of received signals are shown to be necessary; and some of the results obtained by their use in cennection with diurnal and seasonal variations of transmission are given. The simultaneous appearance of disturbances of reception at widely separated points is investigated and found to exist, and it is concluded that the source of such widespread disturbances may be in iron-containing portions of the earth's crust subject to varying magnetic fields and with a stepwise altered magnetization according to the Barkhausen effect.