Long-Distance Radio Telephony

Abstract

THE successful transmission of speech from New York -L to London, which took place in the early hours of the morning of January 15, shows that the difficulties of long-distance radio telephony are being overcome. The main difficulties are due to absorption of the radio-waves and the muffling of the sounds produced by extraneous noises due to atmospheric disturbances. By carrying out the experiment at night, when the absorptive effects are a minimum, and during the winter months, when the atmospheric disturbances are least, the chances were all in favour of a successful issue. During the first half-hour of the two hours' test, however, the cracklings due to the atmospheric disturbances were plainly audible. Since January 1 measurements have been made daily at the New Southgate Works of the Western Electric Co., Ltd., of the intensity of the signals and of the atmospherics respectively. The results for the first fortnight show that the amplitude of the disturbance due to the atmospherics was less than ten per cent. of the average amplitude of the signals for fourteen hours out of the twenty-four. At this period of the year it is only from? P.M. to 11 P.M. Greenwich time that transatlantic telephony is unsatisfactory. When the measurements have been carried out systematically for a year, it will be possible to estimate with fair accuracy the cost of a radio transmission system of satisfactory quality.