System Design for the 

 North Atlantic Link 



By H. A. LEWIS,* R. S. TUCKER* G. H. LOVELL* and 



J. M. ERASER,* 



(IManuscript received September 7, 1956) 



The purpose of this paper is to examine the design and performance of 

 the North Atlantic link, including consideration of factors governing the 

 choice of features, a description of the operational design of the facility, and 

 an outline of those measures available for future application in the event 

 that faidts or aging require corrective action. 



DESCRIPTION OF LINK 



That portion of the transatlantic system which connects Newfound- 

 land and Scotland consists of a physical 4-wire, repeatered, undersea 

 link of Bell Telephone Laboratories design, with appropriate terminal 

 and power feeding equipment in cable stations at Clarenville and at 

 Oban. 



The various elements comprising the link are shown in block form 

 in Fig. \. The termination points at each end of the link are the Group 

 Distributing Frames (GDF), where the working channels are brought 

 down in three groups to the nominal group frequency band 60-108 kc. 

 At the west end, this point provides the interconnection between the 

 North Atlantic and the Newfoundland-Nova Scotia links. At the east 

 end, it is the common point between the North Atlantic link and the 

 standard British toll plant over which the circuits are extended to 

 London. 



Two separate coaxial cables connect Clarenville with Oban, one 

 handling east-to-west transmission, the other west-to-east. Each is 

 about 1,940 nautical miles long. A total of 102 repeaters are installed in 

 the two cables, at nominal intervals of 37.5 nautical miles. The cables 

 also contain a number of simple imdersea equalizers which are needed to 

 bring system performance within the specified objectives. 



The working spectrum of each cable extends from 20 to 16-4 kc, pro- 



* Bell Telephone Laboratories. 



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