SUN SPOTS AND RADIO — STETSON 



223 



In making plans for research at the new Perkins Observatory at 

 Dehiware, Ohio, it was decided to use the opportunity to further 

 the present investigation by establishing an additional station in 

 the middle West at one-third the distance from WBBM over which 

 we were operating in Massachusetts. Another observer, Mr. Brown, 

 of Pasadena, Calif., is gathering similar data from a Pacific coast 

 station. The continuance of the Boston data is assured through the 

 cooperation of G. W. Kenrick at the Tufts College Laboratory, 

 Med ford, Mass. 



Now, every night, Sundays and holidays included, stations in Mas- 

 sachusetts, in Ohio, and in California tune in on a prescribed wave 

 length to study the effect of the day's solar radiation ujpon the elec- 

 trical state of the earth's atmosphere. 



50 ^ 



July 

 1926 



July 

 1928 



FiGUEB 9. — Upper curve is inverse of running mean of sun-spot numbers. Lower curve 

 running mean of radio signal strength received at Boston from WBBM Chicago 



In addition to the measurement of radio reception, the sun is pho- 

 tographed at the Perkins Observatory every clear day in cooperation 

 with the Yerkes, Mount Wilson, Harvard, and Naval Observatories, 

 and a careful study made of the size, numbers, and location of the 

 sun spots. It is believed from a preliminary study that the distance 

 of the spots from the center of the disk, or the sun-earth line, is an 

 important factor in the study of correlation of sun spots with radio 

 reception and other electromagnetic phenomena on the earth.'' 



The radio apparatus in use at the Perkins Observatory is a super- 

 heterodyne receiver especially constructed for the purpose, and feed- 

 ing into a self-recording galvanometer which registers the strength 

 of the carrier wave received from the broadcasting station of WBBM, 

 Chicago, and WJZ, New Jersey. The apparatus is so designed that 



1 Pickard, Proc. Inst. Radio Eng., vol. 15, no. 12, December, 1927. 



