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BELL SYSTEM TECHNICAL JOURNAL 



with the diameter of the central conductor than is the case with low- 

 frequency cables, either telephone or telegraph. The particular factor 

 contributing to this result is the large skin effect, which occurs prin- 



81° 

 FLORIDA 





I-'ig. 1 — Submarine telephone cables between Key West and Havana, and 

 U. S. land line connection. 



cipally in the central conductor but also appreciably in the return 

 tapes. The ratio of the a-c. to the d-c. resistance increases at a rapid 

 rate if the central conductor and return tapes are made heavy in an 

 attempt to reduce the weight of the insulation. At carrier frequencies 



