Repeater Design for the 

 Newfoundland-Nova Scotia Link 



By R. A. BROCKBANK,* D. C. WALKER* and 

 V. G. WELSBY* 



(Manuscript received September 15, 1956) 



The Newfoundland-Nova Scotia cable required the provision of 16 sub- 

 merged repeaters each transmitting 60 circuits in the bands 20-260 kcfrom 

 Newfoundland to Nova Scotia and 312-552 kc in the opposite direction. 

 The paper deals with the design and production of these repeaters. Each 

 repeater has a gain of 60 db at 552 kc, and the amplifier consists of two for- 

 ward amplifying paths with a common feedback network. Reliability is of 

 paramount importance, and production was carried out in an air-condi- 

 tioned building with meticulous attention to cleanliness and to very rigid 

 manufacturing and testing specifications. The electrical unit is contained 

 in a rigid pressure housing 9 feet long and 10 inches in diameter with the sea 

 cables connected to an armor clamp and a cable gland at each end. A 

 submerged equalizer was provided near the middle of the sea crossing. 



INTRODUCTION 



The British Post Office has engineered many shallow-water submerged- 

 repeater systems/ and there has been a progressive improvement in de- 

 sign techniques and in the reliability of components which has been re- 

 flected in a growing confidence in the ability to provide long-distance 

 systems having an economic life. The seven-repeater scheme from Scot- 

 land to Norway laid in 1954 introduced for the first time repeaters which 

 would withstand the deepest ocean pressure together with an electrical 

 circuit which embodied improved safety and fault-localizing devices. 

 Also, since a repeater is only as reliable as its weakest component, much 

 greater attention and control was directed at this stage to the design, 

 manufacture and inspection of all components, both electrical and me- 

 chanical. This repeater design was, in fact, envisaged as a prototype for 

 a future transatlantic project. 



* British Post Office. 



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