GB537118A - Improvements in radio self-indicating bearing finders - Google Patents

Abstract

537,118. Directive wireless systems. TELEFUNKEN GES. FUR DRAHTLOSE TELEGRAPHIE. Dec. 6, 1939, No. 31640. Convention date, Dec. 6, 1938. [Class 40 (v)] Signals from two crossed frame aerials R1, R2, Fig. 7, are combined with those from a non- directional aerial H through a reversing switch U1 so that the two frames are coupled successively and with alternating polarity to the receiver E, whilst the output from the receiver is applied through a switch U2, operating synchronously with the switch U1, to two indicator coils A1, A2, also set at right-angles to each other, so that, when one of the two aerials R1 or R2 is connected to the receiver input, the corresponding indicator coil A1, or A2 is connected to the output with like polarity. Fig. 8 shows the working sequence of the input and output switches U1, U2; the polarity of the frame R1 is first kept in step with that of the winding A1, and similarly that of the frame R2 and winding A2, at the next movement of the switch and so on. In Fig. 10 the input switch U1 comprises four salient magnetic poles, two of which c, d are coupled to the frame aerials .and two e, f to the receiver E. The rotating core g is partly screened as shown, so that first the flux in pole c induced by the aerial R2 is transferred through the pole f to the receiver E, and next the flux induced by the aerial R1 is similarly coupled to the receiver through the poles e and f. The output switch U2 consists of a brush rotating over commutator segments connected to the two indicator coils A1, A2. The coils A1, A2 may operate a pair of astatic needles located either inside or outside a magnetic core (Fig. 13 to 16 not shown). The direction-finder described may be used in combination with a " homing " indicator, the windings of the two instruments being connected in opposition ; this will indicate any deviation from the course with great accuracy and sensitivity.