Electrical Oscillations in Antennas and Inductance Coils

Abstract

After considering the theory of circuits having uniformly distributed constants, the author shows graphically the frequency-variation of reactance of such circuits and, after further analysis, those of inductance-loaded and capacity-loaded antennas as well. The calculation of the effective constants of the antenna at radio frequencies in terms of their corresponding values at audio frequencies follows. Very simple relations are found, differing from those frequently given in the radio literature. The equivalent circuits of loaded and unloaded antennas are given, together with practical measuring methods for determining the effective constants at radio frequencies. The frequency-variation of effective resistance of an antenna is then considered. Measurements are described and curves given which indicate that antenna resistance is largely due to imperfect dielectrics in the field of the antenna, and emphasis is placed on the necessity of avoiding such dielectrics in regions of strong antenna field.