DESIGN OF SYSTEM — NORTH ATLANTIC LINK 57 



A special transmission measuring set is provided in the receiving con- 

 sole which facilitates measurements in the crystal frequency region 

 166-175 kc. This set is used for evaluating the performance of individual 

 repeaters from shore. As an oscillator, it is capable of delivering an 

 output of up to +8 dbm into a 75-ohm load, with exceptional frecjuency 

 stability and finely-adjustable, motor-driven tuning. This is useful in 

 locating and measuring the narrow-band response peaks of individual 

 repeater crystals. The oscillator frequency is varied in the region of a 

 particular peak, and the received power is measured at the peak fre- 

 quency and at nearby frequencies. At the peak frequency, the crystal 

 removes nearly all feedback in the repeater. Changes in repeater internal 

 gain can thus be determined from shore. 



As a detector, the set can measure from — 110 to —60 dbm in a band- 

 width of about 2 cycles. This enables it to measure crystal noise peaks 

 which may be spaced as closely as 50 cycles apart. To reduce the random 

 variations in such narrow-band noise, a "slow integrate" circuit, of the 

 order of 10 seconds, is provided. Thus the crystal noise peaks can be 

 compared in magnitude with the system noise level at closely adjacent 

 frequencies. 



ASSEMBLY AND TEST OF SYSTEM 



General 



Assembly and initial testing of the North Atlantic link occupied a 

 span of about three years. Because of the geographical and political 

 factors involved the job was a difficult one and required close coopera- 

 tion among individuals in many different organizations on both sides of 

 the ocean. 



Clarenville 



The cable station at Clarenville houses the carrier terminal, cable 

 terminating and power equipment at the junction of the North Atlantic 

 and Cabot Strait links. It was designed by United States architects 

 from requirements furnished by A. T. & T. engineers and was approved 

 by the other parties to the enterprise. The building was constructed bj- 

 a Canadian firm under the supervision of a Canadian architect. 

 The equipment was put in place and connected by installers of 

 the Northern Electric Company and tested by representatives of Bell 

 Telephone Laboratories, Eastern Telephone and Telegraph Company, 

 Northern Electric Company and the British Post Office. 



As Newfoundland is an island, shipments of equipment and supplies 



