The Loaded Submarine Telegraph Cable

Witht an increase of traffic carrying capacity of 300 per cent over that of corresponding cables of the previous art, the New York-Azores permalloy-loaded cable marks a revolution in submarine cable practise. This cable represents the first practical application of inductive loading to transoceanic cables. The copper conductor of the cable is surrounded by a thin layer of the new magnetic mtaterial, permalloy, which serves to increase its inductance and consequently its ability to transmit a rapid succession of telegraph signals. This paper explains the part played by loading in the operation of a cable of the new type and discusses some of the problems which were involved in the development leading up to the first commercial installation. Particular attention is given to those features of the transmission problem wherein a practical cable differs from the ideal cable of previous theoretical discussions. Brief mention is made of means of operating loaded cables and the possible trend of future development.