1188 THE BELL SYSTEM TECHNICAL JOURNAL, SEPTEMBER, 1953 





§SiM 





9§m 



tig. 1 —Typical records obtained during the Lowden-Princeton, Iowa, fre- 

 quency-sweep transmission measurements. The horizontal scale is proportional 

 to frequencies between 3,750 and 4,150 mc (the single spike on the right is at 4,190 

 mc); and the vertical scale is proportional to the amplitude of the received signal. 



