Measurement of the Natural Frequency of Single Turn coils

Abstract

A two-valve generator of short electric waves at about 2.50 metres wave length could naintain the amplitude and the frequency of oscillation fairly steady and constant.
A receiver was place at the distance of 10 metres, and the coil under test was placed in front of it.
The generator was kept untouched and was sending out constant radiation. The dimension of the coil under test was varied and the intensity in the receiver system was observed. The change of intensity of the received energy was caused by the absorption and refraction by the coil, and the results clearly indicated its resonance point.
The coils tested were equilateral triangle, square and circle, each made of a single closed turn of B.S. No. 10 wire.
Afterwards the coils were cut at a point and a gap of 1cm. was formed. These open turns showed resonsance of the fundamental, the 2nd and the 3rd harmonic oscillations.
Though the accuracy of the measunement is still far from ideal, the results seem to be sufllclent to show that the method is well suited for giving very remarkable effects.