A Method of Measuring Radio Field Intensities and Atmospheric Disturbances

The method of measuring radio signals here described depends on the determination of the equality of the sound intensities in the telephones from the signal and from a known alternating current preferably giving the same tone. The measured local current is taken from a thousand-cycle tuning fork oscillator and the electromotive force impressed on the telephones is controlled by a voltage divider. The errors of measurement may be under good conditions less than five percent, tho in case of spark signals and atmospheric disturbances when the two tones cannot be matched it will be very much greater. Special arrangements are described for measuring very strong signals and atmospheric disturbances.