On the Measurement of Natural Frequency of Coils with Ultra-radio Waves

Abstract

Mr. Y. Nishimura has publishcd a new method of determining the natural wave length of single turn coils of various shapes. By observing the ab orption of electric waves due to the coils, the resonant frequency of the latter can be determined.
In his measurements, there are three points requiring improvements:
1. The absorbing system anl the receiving system are too closely situated. They should be placed farther away fr m each other.
2. The wave length of the radiated wave should be more accurately determiaed.
3. The coils forming the absorbing system must not be placed on the table, but should be frcely suspended in the air.
The whiter has ascertained that the wave length as determined by a parallel wire system well agrees with that determined by observing the resonance of a single rod absorber.
When the above mentioned 3 points are specially taken care of, the measurement at ultra-radio frequency is found to furnish reliatle results. A generator that can radiate waves at constant frequency must be prefered.