GB167584A - Improvements in and relating to thermionic valve transmitting circuits for wireless telegraphy and telephony - Google Patents

Abstract

167,584. Macrorie, A. K., and Shearing, G. May 11, 1920. Thermionic oscillation generators. - In a thermionic valve transmitting circuit for wireless telegraphy and telephony in which the coupling is partly direct and partly inductive, a local circuit coupled to the aerial induces in it a current sufficient to produce drying out when its oscillations stop owing to wet conditions. The anode of the main valve V, Fig. 4, is directly connected to the aerial circuit through the condenser P and its grid is coupled through the coil G. A.n oscillating local circuit containing the valve V and tuned to the aerial circuit causes a current to be induced in the aerial to which it is coupled by the transformer D. High-frequency chokes R, R<1> prevent damping of local oscillations when the aerial circuit is earthed owing to dampness. In another arrangement, Fig. 1, the main valves V, V are in parallel and connected in series with local circuit valves V<1>, V<1> which are also in parallel with one another. The part X of the aerial inductance .contains a fine adjustment Y, a variometer portion Z for " calling up," and has coupled with it the coils C, Q, in the grid circuits of the valves V, V<1> respectively, and the transformer coil D in the local circuit.