RECEIVING ANTENNA FOR MINIATURE RADIO RECEIVER

摘要

1354710 Radio receiving apparatus; aerials MOTOROLA Inc 21 Oct 1971 [30 Oct 1970 4 Oct 1971] 48914/71 Headings H3Q and H4A An aerial for a miniature radio receiver adapted to be carried on a person and having a housing with parallel sides extending vertically in the normal position of the receiver, and with one side therein in proximity to the person, comprises a flat conducting member 16 formed in a U-shaped configuration having first and second elongated substantially parallel arms, 18, 19 respectively, Fig. 2, forming parts of the parallel housing sides and a portion 20 connecting said arms: a reactance network is connected to the ends of the arms 18, 19 opposite to the connecting portion 20 for deriving signals therefrom. In the embodiment a clip 12 is attached to the arm 19 for clipping the receiver to a pocket (Fig 1, not shown): the member 16 forms a cover sliding over the moulded plastic member 14 which houses the receiver, contact being made with the lower ends of the arms 18, 19 being made by means of spring members 22, 23. In one arrangement the clip 22 is earthed and the clip 23 connects to a tap on a variable inductance, one end of which is also earthed: the inductance is shunted by a pair of capacitors connected in series, the common point of which is connected to the base of a transistor in the receiver (Fig. 3, not shown). In an alternative arrangement, the clip 22, Fig. 4, is connected to earth and the clip 23 is connected to a tuning circuit comprising variable inductor 32 in series with capacitor 33. This circuit is shunted by capacitor 35, a diode 36 which prevents overload of the receiver on strong signals and series-connected capacitors 38, 39, the junction between which is connected through choke 44 to battery 45. Battery 45 is connected through switch 48 to terminal 50 to energize the receiver terminal 43 can be used to apply charging current to the battery, and also forms a 50 ohm input to the receiver, for testing purposes.