SUN" SPOTS AND RADIO — STETSON 



225 



intensity or degree of this ionization or electrification of the earth's 

 upper atmosphere would have the effect of bending the ray more 

 abruptly or less abruptly toward the earth and thereupon at once be 

 noticed in the intensity of radio reception. The more rapid changes 

 of this sort are doubtless responsible for the phenomena of fading, 

 with which every radio fan is thoroughly familiar. According to our 

 theory the sun constantly bombards the earth's atmosphere with 

 electrons or bundles of energy of high frequency, which in turn tear 

 apart the positive and negative charges of the atmospheric molecules, 

 in other words, ionize it to a very considerable extent, thus producing 

 the Kennelly-Heaviside layer. If the sun is more active on occasion, 

 as when large spots appear on its surface, the degree of ionization 

 increases, producing substantially the effect of lowering the Kennelly- 



80 



X 



^ 60 

 n; 40 



Zo 



jg23 192.^ 192.5 1926 192.7 \gz8 '929 1930 1931 



FiODRB 11. — Graph of Wolfer sun-spot numbers (3-month running means) showing 

 15-month fluctuation in rising solar activity since last minimum in 1923 



Heaviside layer and upsetting the radio reception. When the sim is 

 again less active, the atmosphere tends to return to its normal state 

 of ionization and the radio broadcasting reception tends to improve 

 as the ionized layer lifts. 



For certain wave lengths it is possible that the effect of a rising 

 and falling ionized layer may actually be the reverse of that noted 

 in the broadcasting zone, giving impaired reception during less solar 

 activity. Curiously enough, this is just what has been observed by 

 Doctor Pickard at the Newton Center laboratory when working on 

 long waves of 18-kilocycle frequency. 



Further study of the data shows a definite 14 or 15 month period in 

 solar activity to be exhibited both in the matter of sun spots and in 

 radio reception. 



Another important result of the study of the reception curve is 

 to show how completely unfounded is the popular impression that 

 radio reception is universally poor in summer and good in winter. 



