Overseas Radio Extensions to Wire Telephone 

 Networks * 



By LLOYD ESPENSCHIED and WILLIAM WILSON 



The development of intercontinental telephony through the agency of 

 radio links connecting between the land networks is traced and its present 

 trends indicated. A description is given of the facilities employed by the 

 Bell System for overseas connections and connections to ships at sea. The 

 transmission results secured with these facilities are set forth and some pecul- 

 iar short-wave phenomena discussed. International problems of frequency 

 use and conservation are briefly summarized. A fairly comprehensive bib- 

 liography of technical papers on transoceanic telephony is included at the end 

 of the paper. 



Introduction 



THE progress which long-distance electric communication is 

 making in tying the world together is perhaps nowhere more 

 interestingly illustrated than in the developments which are now 

 taking place in the interconnection of widely separated wire telephone 

 networks by means of overseas radiotelephone links. It was only a 

 few years ago, in 1927, that telephone service was first extended across 

 the barrier of the North Atlantic and a beginning made in the inter- 

 connection of the great telephone networks of North America and of 

 Europe. Rapid progress has been made since then in the further de- 

 velopment of the North Atlantic facilities and in the extension of 

 radiotelephone links from these wire telephone networks outward in 

 other directions, until today such links span a large portion of the 

 globe. 



Since it is the nature of telephony that the circuits are employed 

 personally by the telephone users it is necessary that these inter- 

 connecting links be of a high standard of transmission effectiveness 

 and be free from interference. Also it is important that they be 

 reliable in operation and continuously available during the operating 

 periods, for the usefulness of telephone service is in part dependent 

 upon its being immediately available on call. Although these re- 

 quirements are not yet being fully met, the circuits already in opera- 

 tion are very effective and are proving to be valuable additions to the 

 world's communication facilities. 



The progress which is being made and the problems which are 



arising in the establishment of these systems and in the coordination 



* Presented before Fifth Annual Convention of the Institute of Radio Engineers, 

 August, 1930; Proceedings of 1. R. E., February, 1931. 



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