GB346780A - Improvements in and relating to mains-operated wireless receiving apparatus and the like - Google Patents

Abstract

346,780. Wireless receiving systems. SAVAGE, L. F., 20, Old Compton Street, London, WRIGHT, E. H. M., Limberloft, Coppice Drive, Wraysbury, Buckinghamshire, and RADIOVOLT, Ltd., Kingston Road, Staines, Middlesex. Jan. 14, 1930. Nos. 1364, 14856, and 16082. [Class 40 (v).] In a mains-operated wireless set, one or more of the conductors a of the mains is used as an aerial and another a<1> as an earth. A mains transformer b has two secondaries supplying respectively the high- and low-tension currents, and the aerial and earth connections to the mains are made in parallel with the transformer through two condensers c .. d<1> in series, the one adjacent the mains of high capacity and the other of relatively small capacity. Alternatively a single fixed or variable condenser of small capacity is included in one or both connections (Fig. 2, not shown). To improve the selectivity an auxiliary aerial consisting of a wire or a metallic plate or the like is connected to the aerial circuit. According to modifications the connections to the mains are made indirectly through a high-frequency transformer, Fig. 3 (not shown), or an autotransformer, Fig. 4 (not shown), in series with a condenser, or to a potentiometer, Fig. 5 (not shown), or to the middle point of two resistances or two condensers in series in shunt across the mains, Fig. 6 (not shown).