Determination of Electrical Characteristics of Loaded Telegraph Cables

T h e use of permalloy for c o n t i n u o u s loading h a s i n t r o d u c e d a n u m b e r of new f a c t o r s of i m p o r t a n c e in t h e s t u d y of transmission of signals over long s u b m a r i n e telegraph cables. D a t a to check t h e theoretical a s s u m p t i o n s t h a t a r e used in t h e design of permalloy loaded cables can be o b t a i n e d by measuring on such cables t h e a t t e n u a t i o n a n d t i m e of p r o p a g a t i o n of sinusoidal c u r r e n t s of v a r i o u s frequencies in t h e telegraph range. By combining t h e results of these m e a s u r e m e n t s with d a t a o b t a i n e d on t h e cable d u r i n g process of m a n u f a c t u r e , t h e resistance, i n d u c t a n c e , c a p a c i t y a n d leakance of t h e cables can be d e t e r m i n e d . T h i s p a p e r describes t h e e x p e r i m e n t s t h a t were p e r f o r m e d o n t h r e e laid cables a n d discusses in a general w a y t h e m e t h o d s of c o m p u t i n g t h e cable p a r a m e t e r s .