Patent GB-445968-A (GB)
Title: Improvements in or relating to aerial systems
IPC: H04N5/60
Filed: 1934-08-17
Abstract: 445,968. Wireless receiving systems. CORK, E. C., 50A, Kenilworth Road, and BLUMLEIN, A. D., 7, Courtfield Gardens, both in Ealing, London, and WHITE, E. L. C., 32, The Rise, Hillingdon, Middlesex. Aug. 17, 1934, No. 23793. [Class 40 (v)] A wireless receiving system is adapted for simultaneous reception of short and long waves by the use of a short-wave aerial coupled by a feeder to a short-wave receiver, the feeder acting as an aerial for the long-wave reception. As shown in Fig. 1, the feeder from the shortwave aerial comprises a central conductor 17 within a cylindrical sheath 18. The conductor 17 is connected by a small condenser 20 to a tap 21 on the tuned input coil 2 of the short-wave receiver S, or alternatively is coupled thereto by a transformer. The sheath 18 is earthed as regards short waves by a series-tuned circuit 23, 24 and is connected to a tap 22 on the tuned input coil 10 of the long-wave receiver L. In a modification shown in Fig. 3, the aerial system 27, 29, 30 is remote from the receivers S, L and an intermediate coupling system 31 is provided. Short waves are transmitted from aerial 27 through the conductor 29, 30, transformer 34, and outgoing feeder 35 to the short-wave receiver S. Longer waves picked up by the feeder 30 are led to the earthed casing 31 through branched circuits 42, 38 and 43, 39. The secondaries of the transformers 38, 39 are connected through feeders 47, 48 to transformers 51, 52, which transfer signals of the mediumwave band or the long-wave band to the tuned receiver L. In the circuit shown in Fig. 4, a single feeder 35 connects the coupling- system 31 to the receivers S, L. Short-waves are transferred through transformer 34 the secondary of which is connected to the earthed casing 31 by a circuit 58, 59, series-resonant for the short waves. The lead 37 of the feeder includes a coil 62 for coupling to the short-wave receiver S, and is connected to earth through another series-resonant circuit 63, 64. Longer waves are transferred to the long-wave receiver L through the same feeder 35 by means of a connection 60 to a coil 61 connected between the sheath 30 and earth, and by means of a connection to a point 22 on the tuned input circuit of the long-wave receiver L. In a modification, Fig. 5 (not shown), of the coupling system 31 of Fig. 4, the short-wave feeder 29 from the aerial is connected through a condenser to the feeder wire 37, the transformer 34 being dispensed with. Tap 60 on the coil 61 is connected to the feeder 37 through a parallel-tuned circuit resonant to the short waves. At the receivers, the signals may be separated by a small condenser feeding the short waves to the receiver S, and a short-wave parallelresonant circuit feeding the long-waves to the receiver L, Fig. 6 (not shown). When long and short waves are fed to a receiver through symmetrical balanced wires and a balanced transformer, the centre point of the transformer primary is effectively earthed by a series-resonant short-wave circuit, and is also connected to the long-wave receiver. The transformer secondary coil feeds the short-wave receiver. The short-waves may carry television signals, and the longer waves telephony signals. Specification 424,239 is referred to.