SOME APPLICATIONS OF TYPE "J" CARRIER SYSTEM 341 



the immediate relief, four suitable J carrier paths were provided of 

 which one on each line was needed in 1938. Figure 2 is a typical pole 

 head and shows how the ultimate circuit capacity of this open-wire 

 plant has been expanded from 69 to 133 circuits by the addition of one 

 crossarm and eight conductors. The use of 128-mil wire instead of 

 104-mil wire provides greater strength and, considering the particular 

 location, reduces the probability of interrupting sixteen circuits by a 

 single wire break or other physical interference. 



12 J 

 3 c 



12 J 



3 C 



r\ P X 



aa 



12 J 

 3 C 



r-\ P^ 



12 J 

 3 C 



I p 



I PX 



/^3C„v /^3 C^ 



QisQ Qisa Q 



I PX , r- 



ii JQ- a! JQ- -a' 



, 1 PX -^ 



;q? JQ' ^Qi sq" "a 



/—~ I PX — ^ r~ 



"Hi sB' "^a'l sQ' ^a 



-7 s' P'^ is^ - 



fa' ^Q" ^' ^ tf 'a 



? ;;- 



, I PX X 



^ a- -alia- -QJ Ja; 



/ 1 PX \ 



/„3 C^s /t3 C3 



Bisa aisB 



, 1 PX , 



I -Q!id-%lg£ 





. 



LEGEND 



_^ P = PHYSICAL CIRCUIT 



^^ PX= PHANTOM CIRCUIT 



S ' SIDE CIRCUIT 



C = "C"CARRIER CIRCUIT 



= "D"CARRIER CIRCUIT 



J = "j"CARRIER CIRCUIT 



Fig. 2 — Pole head diagram showing circuit capacity of the Dallas-Houston and 



Dallas-San Antonio lines. 



The program of placing three type J carrier systems in service in 

 Texas during 1938 was established. Figure 3 is a map of a portion of 

 the state showing the routes of the lines and the principal cities along 

 the routes. Since the length and attenuation of each of these lines are 

 such that the carrier systems can not operate without intermediate 

 amplification, it was necessary that the number and locations of 

 repeater stations be determined. 



Typical System 



The layout of a particular system is largely controlled by available 

 repeater gain, existing entrance cables, line attenuation under normal 



