274 THE BELL SYSTEM TECHNICAL JOURNAL, JANUARY 1957 



and Submarine Cables, Ltd., for their unsparing efforts to ensure the 

 very highest standards in the engineering, production and testing of 

 these repeaters. Numerous firms have also co-operated in specialized 

 fields, and the authors are very appreciative of their help. The authors 

 also wish to acknowledge the enthusiastic assistance of their many 

 colleagues in the Research Branch of the Post Office in the design and 

 in the supervisory inspection during manufacture. Finally a grateful 

 acknowledgment is made to the Engineer-in-Chief of the British Post 

 Office for permission to publish the paper. 



Appendices 

 1 performance of typical submerged repeater 



(a) Insulation resistance 8000 megohms (cold) . 



(b) DC resistance at 20°C. 



Current, ma DC resistance, ohms 



5 343.0 



20 343.2 



50 344.2 



100 347.9 



(c) Voltage drop at 316 ma 124 volts 



(d) Carrier gain (55 ohms) without moisture detector. 



Frequency, kc Gain, db Frequency, kc Gain db 



20 11.54 308 44.52 



30 13.82 312 44.87 



50 17.47 320 45.56 



100 25.06 330 46.29 



150 30.86 350 47.75 



200 35.81 400 51.19 



230 38.40 450 54.20 



260 40.96 500 57.31 



264 41.13 552 60.01 



268 40.83 



(e) Noise level. 



A terminal (312-552 kc) -59.8 dbm 



B terminal (20-260 kc) -70.3 dbm 



(/) Harmonic level. 



170 kc fundamental level at B terminal +10 dbm 



340 kc second harmonic level at A terminal — 60 dbm 



510 kc third harmonic level at A terminal —58 dbm 



