156 



BF.Ll. SYSTEM TECHKICAL JOIRSAL 



of the characteristic imix-chince of the Tallulah F"alls-Gainesville 

 line of the Georgia Railway and Power Company at three different 

 frequencies. 



The attenuation of the line was then measured by terminating it 

 in its characteristic impedance and measuring the current in to the 

 line and current out of the line.'' The results of the attenuation 

 measurements made on the Tallulah Falls-Gaines\ille line are shown 

 on Fig. 3. The irregularities in the attenuation shown by the Idwvr 



racQvtHct- MLOCrCLfS 



I'ig. 4 — In)|K>(laiue Cliaraclerislirs at Carrier Frequencies of a Typical (i()00:l KHMH) 

 \'olt Transformer Bank 



cur\e are |)robal)l\' caused !)>• ihe error in assuming that the phase 

 angle of the surge impedance was small and that the surge impedance 

 was a straight line function of fre(|uency. Frt)m these and other 

 data it .was evident that for frequencies as high as l.")0 K.(", the 

 attenuation is not excessisi'. 



IIk.II I'KKyfEXCY C"lI.\KA( THklsrUS Ol- I'()\V1:k Tr.wsiormkks 



In order to determine the effect of power transformers on the use 

 of the power line as a transmission medium for high frequenc>- currents, 



• .Attenuation expressed in transmission units is equal to 20 logic t'- where /i is 



the current mto the network and /> is the current received from the network and 

 measured in a circuit whose impc<hince corresponds to the characteristic impedance 

 of the network. 



