North Atlantic Ship-Shore Radiotelephone Transmission during 1930 and 1931

Considerable data on radio transmission were collected during the years 1930 and 1931 incidental to the operation of a ship-shore radiotelephone 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.