GB212348A - Improvements in or relating to wireless navigational apparatus - Google Patents

Abstract

212,348. Walker, N. Cox-, and Gill, T. H. Jan. 1, 1923. Bearings, determining; directive signalling.-In a navigational system, the direction of the magnetic meridian is determined by rotating a coil in the earth's magnetic field, the current generated serving to operate an indicating device, and wireless indications of the direction of a transmitting station are given in the same indicating device. The magnetic meridian determining apparatus may be such as described in Specification 210,948, [Class 37, Electricity, Measuring &c.]. As shown in Fig. 1, it comprises a coil 2 rotated by a wind or electric motor having commutator segments 4, 5 co-operating with brushes 6, 7 mounted on an adjustable ring 8. The electromotive force generated by the coil 2 is applied through a transformer 18, 20 to a low-frequency amplifying valve 16 and produces a note in the telephones 17. A condenser 19 connected across the primary 18 of the transformer serves to increase the electromotive force generated in the secondary winding 20. In a modification, only one of the brushes of each pair is employed. The direction-finding apparatus shown is of known form and comprises two loop aerials 11, 12 arranged at right-angles to ons another connected in series by means of a reversing switch 13 and operating telephones 17 through valves 14, 15. Fig 2 shows a modification of the low-frequency amplifier adapted to avoid alteration of the circuit of standard amplifying apparatus, in which, as in the apparatus shown in Fig. 1, the low-frequency hum due to the meridian-finding coil is heard in the telephones 17 as well as the direction -fnding wireless signals.