A Simple Method of Measuring Electrical Earth-Constants

In a wireless wave, moving over the surface of the earth, the electric force existing because the earth is not a perfect conductor is not vertical but is tilted forward slightly. It has therefore vertical and horizontal components which, in addition, happen to be out of phase. The ratio of these components and also the phase angle depend on the conductivity and dielectric constant in a theoretically calculable manner. An experimental determination of this ratio and phase angle leads, therefore, to a value of these earth constants. A method is described of making these determinations, using nothing more than an ordinary receiving set and the human ear. An incoming signal is received in succession on two short equal aerials inclined to the ground, one in the direction of the transmitting station and the other at right angles to this direction. The signal strength using either depends on the height of its free end. With the first aerial fixed, the height of the free end of the other can be adjusted until the signals are of equal strength. The first aerial is affected by both components, and the second only by the vertical components so that the equality of signals gives an equation involving the ratio of the components and the phase angle. Another experiment with a different fixing of the first aerial gives a second relation, and the two equations suffice to give both the ratio and the phase angle.