A Method of Exciting the Aerial System of a Rotating Radio Beacon

This paper describes a novel method of feeding the spaced-aerial system of a radio beacon transmitter, which has arisen from the consideration of the possibilities of the application of the Adcock-aerial principle to such a beacon. A brief discussion is given of the limitations of the ordinary rotating-coil goniometer arrangement for such a beacon when the transmitted power is high. The alternative method described utilizes two power amplifiers to feed the two pairs of spaced aerials. These two amplifiers are supplied with radio-frequency voltages by means of a mechanical controller which automatically provides the required time/voltage variations. A description is given of this controller, together with its application to the problem of exciting the two amplifiers. It is shown that such a controller can fulfil the requirements of the excitation apparatus, and it is concluded that the system described would be suitable for incorporation in a full-size rotating radio beacon for marine navigational purposes.