Extraneous interference on submarine telegraph cables

In order to avoid a considerable reduction in speed of operation, which would have resulted on account of the unusually large parasitic disturbances encountered in the neighborhood of New York, the New York-Azores permalloy loaded cable was equipped with a new type of earth connection consisting of a conductor extending 100 nautical miles to sea and there connected to earth through an artificial line. This paper presents the theory of the new type of sea earthing arrangement and discusses the sources of extraneous interference and the manner in which it is picked up by submarine cables. A method is developed for estimating the magnitude of terminal extraneous interference in the case of any particular cable.