CARRIER SYSTEMS ON TELEPHONE LINES 



583 



mean that if the circuit were set up to have a proper volume of trans- 

 mission in dry weather and rain occurred over the whole line it would 

 cause the speech at the receiving end to drop to but 1/180 of the 



300 



.250 



2.200 



a. 

 u 



Q. 



z 



=>.)50 



z 

 o 



«0 

 10 



2.100 

 < 



.050 



10 20 30 40 



FREQUENCY- kilocycle: 5 



50 



Figure 10 — x'\ttenuation curves for open-wire lines of different gauges 

 at iiigh frequencies 



desired volume if the proper readjustments of gain at the repeaters 

 and terminals were not made. Fortunately, these line variations 

 occur gradually, at least in the case of the longer lines. 



In connection with most carrier installations measurements are 

 made "* of line characteristics prior to the installation of the apparatus. 



* Reference, "High-Frequency Measurements of Communication Lines," by H. 

 A. Affel and J. T. O'Leary, A. I. E. E. Transactions, V. 44, 1927, pp. 504-513. 



38 



