358 



KELI. SVSTFM TECHX/C.IL JiHKXAL 



Horta, I'a\al, and rc-iei\t_-(l al New ^'llrk• at a speed <il \,'*'2i) letters 

 per mi mile. 



!t is |)riiuipall\- with regard to the first of these classes of problems, 

 that (»l llie transmission of signals, that llu- following discussion is 

 concerned. .\n attempt will lie m.ide lure in discuss the details of 



SI I 



l.s 



HIS 



:i< 



Fig. 2 — Test Message. Western I iiioii .New N'ork-.Azores Permalloy -LoadKl 

 Cable. Sent from Horta (Azores) and received at New York, November 14, 1924. 

 Speed — 1920 letters per minute. Recorded with special high speed siphon recorder 



design and tie\elopmeiU ot the physical striieliire of the cable, nor 

 will there be given a detailed description of the operating results or 

 how they were obtained. These subjects must be reserved for later 

 publication. It is desired in what follows to explain how^ inductive 

 loading impro\'es the operation of a submarine cable and to point 

 out some of the |)rol)lems concerned with the transmission of signals 

 which had in lie considered in engineering the first long loa<ied cable. 



I-"a( TORS LiMiriNc Si'i'.i-;!) nt Xon-Lhadi-.I) (ahii: 



In onler to muk'rstand the part played b\- loading in ihe trans- 

 mission of signals it is desirable first to review brieth llu' status of 

 the cable art prior to the introduction of loading and io consider the 

 factors then limiting cable speid and the pnssii)U- means of over- 

 coming them. A cable of the ordinary l>'pe, without loading, is 

 essentially, so far as its electrical properties are concerned, a resist- 

 ance WMth a capacity to earth distributed along its length. .Although 

 it does ha\e some inductance, this is loo small to affect transmission 

 at ordinary sjieeds of operation except on cables with extremely heavy 



