Patent GB-129336-A (GB)
Title: Improvements in and relating to Aerial Circuits for Wireless Telegraphy and other purposes.
Inventor: WATT ROBERT ALEXANDER WATSON
IPC: G01S3/12
Filed: 1917-10-24
Abstract: 129,336. Watt, R. A. W. Oct. 24, 1917. Directive wireless signalling; aerials.-A wireless system for directive propagation and reception comprises directional aerials connected with the fixed coils of a radiogoniometer, the movable coil of which is associated with the compound non-directional aerial formed by connecting the directional aerials to each other and, if desired, to earth. As shown in Fig. 1, the circuits of two closed directional aerials a, a<1> include the fixed goniometer coils b, b<1> and tuning-condensers c, c<1>. Each of the latter condensers c, c<1> is shunted bv a divided condenser d, d<1> the intermediate plates of which are connected to each other and to earth through a switch f. The earth connexion also includes the movable coil g of the goniometer, an inductance coil h, and an auxiliary tuning-inductance l or capacity m. The leads k are connected to the detecting or exciting circuit, and a variable condenser j is placed across the leads. Alternatively a coil n coupled to the coil h may be connected to the exciting or detecting circuit. In using the apparatus for reception, the switch f is opened, and the aerial circuits a, a<1> are tuned to the incoming waves by jointly varying the capacities c, c<1>, d, d<1>, the movable coil g determining the direction of the waves in known manner with an ambiguity of 180 degrees. The switches f, i are then. closed and the coil g put in circuit, and the compound aerial thus formed is then tuned without deranging the tune of the independent aerials. This tuning may be effected by placing in circuit the inductance l or capacity m, or both, by means of a switch moved jointly with the switches f, i. The coil g then determines the direction of the incoming waves without ambiguity. The coil g may be placed in series with the condenser j and with an inductance, which may be part of the coil h or a separate coil coupled thereto. The connexions from the divided condensers d, d' to the aerials may be beyond the coils b, b<1>, and the condensers c, c' may be omitted. If the condensers c, c<1> are of small capacity, the condensers d, d<1> may be dispensed with, and the two aerials may be connected at one side of the condensers c, c<1>, In a modification, Fig. 5, the direct connexion between the aerials a, a<1> is omitted, the four coils b, b<1> being coupled to coils B, B<1> each of which is connected at its ends to the quadrants of compound condensers C, D. The central plate of the condenser C is connected to the switch f and coils g, h as shown in Fig. 1, and may, if desired, be earthed by the switch i. The condenser D may be replaced by direct connexions between the leads. The compound aerial may be used, if required, as a non-directional receiving- aerial by connecting the detecting-circuit to a separate coil and by cutting out the movable goniometer coil g, or as a transmitting-aerial by replacing the movable inducing-coil by a coil directly or inductively coupled to the compound circuit, but having no direct influence on the coils b, b'.