Transoceanic Radiotelephone Development

Marking the tenth anniversary of the beginning of commercial long-distance radiotelephone service, the paper reviews: (1) Technical advances over the older radiotelegraph and short distance radiotelephone arts which made the initiation of long-distance service possible. These included water-cooled tubes, single-side-band suppressed-carrier transmission, and voice operated switching devices designed to prevent singing in combined wire and radiotelephone connections. (2) Engineering developments without which the growth of such services would have been severely restricted. The more important are short-wave transmission, accurate frequency stabilization, and privacy methods. (3) Certain further improvements of less uiniversal application. (4) Present outlook for future development. In most immediate prospect are the extensive application of single-side-band reduced carrrier in short-wave commercial operation and the commercial use of a new and improved method of receiving known as a multiple unit steerable antenna. The possibilities of applying grouped channel and multiplex methods to radio transmission are considered. The treatment is brief but comprehensive, being intended to interest the general engineering reader. A bibliography is attached.