GB648713A - Improvements in or relating to radio direction finders - Google Patents

Abstract

648,713. Automatic control systems for radio direction finders. MARCONI'S WIRELESS TELEGRAPH CO., Ltd. March 4, 1948, No. 6817. [Class 38 (iv)] [Also in Group XL (c)] In a switched cardioid radio direction finder synchronous input and output switching is effected by two pairs of contacts on an electromagnetic vibrator and two further pairs of contacts producing an alternating potential synchronous with the cardioid switching may be used to provide one input to an electric motor used to automatically align the aerial system with the incoming signal. The vibrator may be of the type used in car radio receivers, the armature 7 being earthed and being actuated by a coil 1 connected to the lowtension source 3 in series with contact 6. Contacts 8 serve to provide a square switching wave-form applied to device 16 to alternate the polarity in which the output of omnidirectional A is applied to receiver 17 to which the loop aerial L is also coupled. One output of receiver 17 is applied for alternate half cycles of the switching frequency to indicator 22 under control of contacts 9, this arrangement is described in Specification 647,804, [Group XL (c)]. Further contacts 23<SP>1</SP>, 24 generate a wave of the cardioid switching frequency across the secondary 30 of a transformer which is fed to one phase winding 33 of a motor 32, the other winding 34 being fed with the output of receiver 17. Motor 32 provides the drive to rotate loop aerial L until the receiver 17 gives zero output when the motor stops.