1004 THE BELL SYSTEM TECHNICAL JOURNAL, SEPTEMBER 1954 



and Belle Plaine tandem, a distance of about 16 miles. Without repeaters 

 these trunks would have been operated at a loss of about 10 db but with 

 the repeaters they are operated at about 2 db. The only alternative to 

 using E repeaters in this specific case would have been to use the more 

 expensive hybrid-type repeaters. 



In some cases similar to this one, it was found practicable to temporize 

 by installing the series repeater first and operating it at limited gain 

 until the shunt element became available. Later, when the production of 

 the shunt element was started, the additional units Avere added and 

 full advantage of the new series-shunt design utilized in reducing the 

 equivalent of the trunks to the lowest value permitted by echo return 

 loss considerations. 



The third example shown on Fig. 5 is in the city of Pittsburgh between 

 Churchill tandem and the town of New Kensington, approximately 17 

 miles. Here the transmission on existing 19-gauge loaded cable without 

 a repeater would have been about 8 db. The repeaters reduce this figure 

 to between 2 and 3 db which should be satisfactory in this case. It should 

 be noted, however, that 22-gauge with two repeaters would also provide 

 a low enough equivalent, and should it become necessary to supple- 

 ment the present cable at some future date, there will be an opportunity 

 for further savings from the E23 repeaters. 



J NEW 



'KENSINGTON 



4 ^ 



Fig. 5 — Typical E23 repeater application; Pittsburgh toll connecting trunks. 



