Overseas radio extensions to wire telephone networks

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. The circuits already in operation 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 of them into a world-wide telephone network appeal to the imagination and challenge the best efforts of communication engineers. Especially is this development of interest to radio engineers since in this pioneering stage the interconnecting links are being forged by radio. Work is also going forward in the development of new types of submarine telephone cables for this purpose and undoubtedly such cables will in time play a large part in fortifying the more important of the world routes. The radio part of the picture is, however, quite enough in itself and this paper is, therefore, largely confined to this phase of the subject. There is given first, a sketch of the wire telephone networks and the interconnecting links as they exist today, second, a picture of the transmission results which are being obtained in the operation of some of these overseas links, and finally, a discussion of the more important phenomena and problems involved in the radio transmitting medium.