On the Production of Short Radio Waves

Abstract

This is the report of experiments made in the Tohoku Imperial University.
The a ethods of producing continuous waves of ultra radio frequences are c'assified, aceording to the principle of action, into three kinds, namely those depending upon:
1. Retroactive coupling between the plate and the grid circuits (crdinally)
2. Ionic oscillation (Whiddington)
3. Eloctronic oscillation (Barkhausen and Kurz)
Special features of the above methods are pointed out.
Lecher wire system is the most accurate arrangemeut for the wave length measurement. In detecting the nodal points on the wires, the thermogalvanometer requires sufileient supply of energy, and the use of the Rubensche Flasche is to be recommended for the cases of weak cscillat ons.
By the metho I of re rnactive coupling between the plate and the grid circuits, wava lengths longer than 1 metre could be generated.
No oscillations were obtained by Southworth's method.
The znoet stable oscillations were produced by the use of two valves. (Holborn) By reducing the dimension of the circuit elements and varying the platc and the grid voltages, oscilhtitions were continuously obtained, finally reaching the stage of electronic osellation of Barkhausen and Kurz.
The authors obtained oscillations even with the plate disconnected, and the shortest wave length of 38 cm. was produced wi h the grad vol age of-300.