The characteristics of submarine telephone cables at carrier frequencies

This paper deals with the electrical characteristics of submarine cables designed to transmit carrier frequencies. The sphere of this branch of communication is outlined, and the general principles of operation and cable design are stated. The use of bridge networks to determine the characteristics of short lengths of cable, and of a completed laid cable, is described. Test data obtained during the manufacture of a carrier-frequency cable are given, and predictions made therefrom are compared with the results of impedance and attenuation tests on the laid cable. Alternative methods of measuring average and high attenuations are specified. In view of the probable future extension of this form of communication, recent improvements in materials and their effect on transmission capacity are considered. The chief improvements are in new dielectrics having considerably less leakance than those commonly used in submarine cables, and in magnetic loading material adaptable to the carrier-frequency range.