Resonance Phenomena in the Low Frequency Circuit of Radio Transmitters

For determining the resonance characteristics of the audio frequency circuits of a radio transmitter, either the primary ampere method or the secondary voltage method may be used. These methods are described. The method of calculation of the total circuit reactance is given, and the important bearing of this quantity on the resonance effects is discussed. Percentage reactance of any portion of the circuit is defined. The extent of detuning the transformer circuit from the generator frequency in quenched spark work, namely about 15 per cent., is given and explained. The transformer circuit of the Marconi trans-Atlantic station at New Brunswick, N. J., is described. Curves giving the results of measurements by the above methods are shown. The advantages of low resistance in primary and secondary of transformers for quenched spark work, and the superiority of the closed core transformer are considered.