Fields caused by remote thunderstorms

The object of the studies described in this paper was to verify the supposition that certain types of short-duration longitudinal voltages appearing in communication circuits are caused by remote thunderstorms. By means of simultaneous directional measurements made in the frequency range below 40 kilocycles at 2 points as much as 900 miles apart, thunderstorms at distances of several hundred miles from one or both of these points have been located with a degree of accuracy great enough to permit conclusive correlation of the storm locations indicated by the directional measurements with the locations of recorded thunderstorms. Methods, equipment, and results are discussed.