NEGATIVE IMPEDANCE TELEPHONE UBPEATERS 



1050 



4.0 



10 12 14 16 



TRUNK LENGTH IN MILES 



26 



Fig. 2 — Illustrative field of use; toll connecting or tandem trunks. 



gauge. In general, it is the practice to select the smallest gauge which 

 will give the required transmission loss. For short distances, the dif- 

 ferential in cost between trunks of different gauges is not large but as 

 trunk length increases it will be found that a smaller gauge trunk with 

 a repeater will cost less than one of larger gauge without a repeater. 

 For example, at 10 miles a 22-gauge circuit with a repeater will cost 

 substantially less than a 19-gauge circuit with no repeater. Also, as 

 transmission objectives are improved, there may be cases where a smaller 

 gauge trunk with two repeaters will be cheaper than a larger gauge with 

 one repeater. Furthermore, in cases where the costs are about equal or 

 even where the larger gauge is slightly cheaper, it will be found that 

 lower losses can be obtained with repeatered circuits and the engineer- 

 ing choice would accordingly favor the smaller gauge. 



Construction costs differ considerably depending on local conditions; 

 hence the differential cost between the various gauges of conductors will 

 differ correspondingly. Howe\-er, for illustrative purposes Figs. 1 and 

 2 have been prepared which utilize average Bell System costs for both 

 outside plant and telephone repeaters. In the case of the E23 repeaters, 

 the experience so far has been somewhat limited so there is a greater 

 degree of unccniainty as to the actual costs than for the older tyjie re- 

 peater or the outside plant constru(;tion. 



Fig. 1 shows the field of use for various conductor gauges when used 

 in interoffice trunks where an over-all transmission objective of 6 db for 



