A Transmitter Modulating Device for the Study of the Kennelly-Heaviside Layer by the Echo Method

The importance is emphasized of sending out "peaks" of very short duration and proper spacing for the study of the radio reflections from the ionized layer in the upper atmosphere by the echo method, and objections to modified alternating-current modulation are pointed out. A method is outlined for modulating the transmitter, based on the sudden pulses of plate-current which occur in an unbalanced multivibrator circuit. The application of this method to the transmitter is described and its effectiveness illustrated by typical recorded signals.