Television transmitting aerials

A reference to the Alexandra Palace television aerial and to the circumstances preceding the expansion of high-power television services in Great Britain serves as an introduction. The various mechanical and electrical considerations which affect the design of a transmitting aerial are then reviewed, particular attention being directed to common-aerial working for vision and sound. The properties of 2-phase aerial systems are discussed, and curves enabling the horizontal radiation patterns of such aerials to be interpreted in terms of impedance measurements on the distribution-feeder system are presented. The development of the Sutton Coldfield aerial is described, details being given of the scheme of admittance correction applied to the distribution feeder. The modifications to this basic design adopted for Holme Moss and the later high-power stations are explained. The paper concludes with speculations on the probable future trend of television transmitting-aerial design.