Aerial circuit for the reception or direction-finding of electro-magnetic waves

摘要

287,491. Nederlandsche Telegraaf Maatschappij Radio-Holland. March 21, 1927, [Convention date]. Directive signalling; frame aerials.-In order to eliminated the open-aerial effect the coupling- coil B, C, Fig. 3, of a frame aerial is wound in two halves on a single core, one left-hand and the other right-hand, but otherwise symmetrically arranged, as shown in Fig. 8, the centre point being earthed at A. The main windings of the frame aerial are also arranged in two symmetrical halves, oppositely wound on the separate supports shown in Fig. 5. The valve input coil DE may be closely wound around the coil BC. The rotating frame T may be combined with an arrangement 1, 2, 3, Fig. 6, for eliminating quadrantal error, as described in Specification 278,743, any undesirable effect on the tuning of the receiver due to the presence of the conductors 1, 2, 3 being compensated by a short-circuited coil 6, revolving with the frame T and variably coupled to an auxiliary fixed winding 7.