A wireless broadcasting transmitting station for dual programme service

The B.B.C. Regional Scheme involves the construction of a number of twin wireless transmitting stations, each capable of radiating simultaneously two programmes on different wavelengths, and each at a power of 50 kW in the aerial. This paper describes the first of these twin transmitters, erected at Brookmans Park, Hertfordshire, to serve London and the Home Counties. The paper deals with the considerations underlying the choice of sites for such broadcasting stations, the type of power supply adopted, and the factors contributing to reliability in operation, as well as with the wireless transmitters themselves. Detailed considerations underlying the design of such transmitters have been avoided in the anticipation that they will form the subject of a further paper; but, nevertheless, some information in regard to the essential and major points in their design is contained herein. The paper deals further with the general station lay-out, the building and the auxiliary services, as well as with low-frequency apparatus for supplying modulation to the transmitter and apparatus for testing and monitoring purposes, etc. Of particular interest is the use of high-tension direct-current machines at this station for the production of high-tension voltage for anode supply to the main power valves. The type of generator developed especially for this work is considered in some detail.