LONG DISTANCE CABLE CIRCUIT 



579 



Typical effective resistance-frequency curves for the loading coils 

 are given in Fig. 8; these curves include current magnitudes greater 

 than those involved in program transmission service. The core eddy 

 current losses, varying with the square of the frequency, are prin- 



O 



— MAKE-UP 



19 QUADS— 16 GAUGE 



6 PAIRS — 16 GAUGE 



114 QUADS — 19 GAUGE 



SHEATH THICKNESS 0.125 INCH 



OUTSIDE DIAMETER — 2.6 INCHES (aPPROX) 



— LEGEND — 



PROGRAM PAIR 



FOUR-WIRE QUAD FOR TRANSMISSION 

 IN ONE DIRECTION (40 QUADS) 



FOUR-WIRE QUAD FOR TRANSMISSION 

 IN OTHER DIRECTION C^O QUADS) 



TWO-WIRE QUAD — 16 & 19 GAUGE 



HEATH 



Fig. 7 — Cross section of typical full sized cable. 



cipally responsible for the resistance increase at the higher frequencies. 

 The increase of attenuation with frequency caused by these core losses 

 is readily corrected, however, by the attenuation equalizers which, 

 as described later, also correct for the attenuation-frequency distortion 

 caused by other factors in the cable circuit. 



X 



o 



UJ 



o 



z 



CO 



tn 



UJ 



a: 



u 

 > 



H 

 O 



u 



10 



30 50 100 200 500 1000 



CYCLES PER SECOND 



2000 



5000 8000 



Fig. 8 — Effective resistance of 22 milli-henry loading coils used on program 

 transmission circuits in toll cables. 



Owing to the low hysteresis loss of the compressed powdered per- 

 malloy material, the non-linear distortion introduced by the loading 

 is inappreciable within the range of volumes handled by this program 

 system. For example, in a 1,000-mile circuit for the condition where 



