Abstracts of Technical Articles from Bell System Sources (01 April 1933)

North Atlantic Ship-Shore Radio Telephone Transmission During 1930 and 1931} CLIFFORD N . ANDERSON. Considerable data on radio transmission were collected during the years 1930 and 1931 incidental to the operation of a ship-shore radio telephone service with several passenger ships operating in the North Atlantic. This paper discusses briefly the results of an analysis of these data. Contour diagrams are given which show the variation of signal fields with distance and time of day for the various seasons on approximate frequencies of 4, 9, 13, and 18 megacycles. Similar diagrams show the distributions of commercial circuits. Curves are also shown which enable the data to be applied more generally for other conditions of noise and radiated power. Short-Wave Transmission to South America.' C. R. BURROWS and E . J . HOWARD. 

The results of a year's survey of transmission conditions between New York and Buenos Aires in the short-wave radio spectrum are presented in this article. Surfaces showing the received field strength as a function of time of day and frequency are given. These show that frequencies between 19 and 23 megacycles were best for daytime transmission, and those between 8 and 10 megacycles for nighttime transmission. A transition frequency was required in the early morning, but the useful periods of the day and night frequencies overlapped in the evening. No variations that could definitely be traced to a seasonal effect were found. This path is much less affected by solar disturbances than the transatlantic.