GB427886A - Improvements in or relating to antenna systems - Google Patents

Abstract

427,886. Wireless receiving systems; impedance networks. PHILCO RADIO & TELEVISION CORPORATION OF GREAT BRITAIN, Ltd., HORNBY, F. R., and HOLIDAY, G. S., Aintree Road, Greenford, Middlesex. Aug. 26, 1933, No. 23782. [Classes 40 (iii) and 40 (v)] A lead-in feeder system comprising a step - down transformer, low impedance transmission line and step-up transformer connected between an aerial and the signal input terminals of a receiver is adapted for use on two wave bands by making the aerial transformer aperiodic, multi-peaked or having a broad resonance curve, the peak of which lies within or near both bands, the receiver transformer being similarly constructed or associated with switching means for varying its natural frequency. The aerial step-down transformer 1, Fig. 1, is connected to the transmission line 2 which feeds the receiver step-up transformer 3, the secondary 4 of which is associated with a switch 6 for short-circuiting a portion thereof when the lower wave band is being received. In a modification, Fig. 2, (not shown), the switch is adapted to connect capacities of different values across the secondary winding. A multi-peaked aerial transformer may comprise a primary 11, Fig. 3, connected to the secondary 12 through condensers 13, 14 the transmission line being tapped across a portion of the secondary. Alternatively, a tertiary winding may be provided, with its centre point earthed, for feeding the line. The receiver transformer may also be multi-peaked and for this purpose condensers 16, 17, 18, Fig. 5, are connected across various portions of the secondary 4. Specification 242,759, [Class 40 (v)], is referred to.