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BELL SYSTEM TECHNICAL JOURNAL 



average of results for each hour's tests. The dash line curve is a 

 smoothing out curve of these points. 



It is interesting to note that these curves of actual word count 

 conform very well in general shape with those of Figs. 11 and 12 

 which also really measure receptiveness although in a less direct 

 manner. Reception is best during the late night and early morning, 



Transatlantic Radio Transmission Measurements 



Diurnal Variation of Words Understood 



Jan. I -Feb. 25, 1925. 



10 1lf2M 1 



Each circle is average of all tests for that hour including 

 triangular points. The latter are known to be cases in 

 which low percentage is due to unnatural causes. 



Fig. 13 



drops off during the day, reaching a minimum during the evening. 

 Furthermore, the night reception is shown to be considerably better 

 for the January-February period than for the February-March period. 

 The curve of Fig. 14 corresponds quite closely with that of Fig. 12. 

 The curve of Fig. 13 does not show as much of a peak as does that of 

 Fig. 11 which is, of course, due to the fact that above a certain ratio 

 the percentage of words understood is high and cannot rise above 100 

 per cent. 



Conclusion 



As has been indicated this is a report of work which is still in progress. 

 To date: 



A new type of radio telephone system affording important ad- 

 vantages for transatlantic telephony has been developed and put 

 into successful experimental operation across the Atlantic. 



Sustained one-way telephonic transmission has been obtained across 

 the Atlantic for the first time by means of this system. 



