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, t h e New York-Azores permalloy loaded cable was equipped with a new t y p e of earth connection consisting of a conductor extending 100 nautical miles to sea a n d there connected to earth through an artificial line. This paper presents the theory of the new t y p e of sea earthing arrangement and discusses the sources of extraneous interference and t h e manner in which it is picked up by submarine cables. A method is developed for estimating t h e magnitude of terminal extraneous interference in t h e case of a n y particular cable.