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Show How Lower Temperature J Improves Radio Signals A study of the variation in strength of signals from the trans-Atlantic radio stations at Tuckertou and New Brunswick, N. J., conducted by Dr. L. W. Austin and Miss L J. Wymore of the bureau of standards, Department of Commerce, and extending oyer more than two years, appears to prove that there is some kind of inverse relationship re-lationship between signal strength and local temperature, though of course this temperature effect Is often masked by other Influences. That is, when temperature Is low, signals aro strong while when the temperature is high, signals are weak. A curve plotted to show monthly averages of temperature and slgnnl j strengths brings out this conclusion very strikingly. The average signals j of February are more than twice as j strong as those of July. The day-by-day relationship Is less marked, varying vary-ing from fairly clear In the winter months to obscure In midsummer. The commonly accepted Ideas re garding the earth's atmosphere indicate indi-cate that there should be no connection connec-tion between the weather near tho ground and conditions at heights of 62 miles or more, where the main variations varia-tions in radio signal intensity are supposed sup-posed to be produced. However, the bureau's Investigations show that the variations in signal strength are actually ac-tually produced In the upper atmosphere atmos-phere and not in the portion of the wave traveling along the ground, because be-cause in the region involved there Is no definite change in intensity as a result re-sult of long continued rains or droughts or because of the presence or absence of snow, at least for wave lengths over 1.000 meters. In addition, addi-tion, it Is hardly conceivable that the rapid intensity changes observed during dur-ing cold waves can be cjue to the penetration pene-tration of frost into the ground, because be-cause this Is of necessity a gradual process. In this Investigation the bureau found It advisable to confine its studies to transmissions from stations at moderate distances, 120 to 370 miles. In the case of more distant stations, weather conditions cannot bo expected to be uniform over the entire en-tire signal path, while for distances less than 120 miles the variations in signal strength for the usual trans-Atlantic trans-Atlantic wave lengths may become too small for profitable study. Experiments are still under way. |
