WIDE-BAND TRANSMISSION OVER COAXIAL LINES 



671 



200 300 400 500 600 700 800 900 



FREQUENCY IN KILOCYCLES PER SECONT 



1000 1100 



Fig. 13 — Temperature regulation — line and repeater characteristics. 



Repeater Operation, Power Supply, Housing, Etc. 



In view of the large number of repeaters required in a broad-band 

 transmission system it is essential that the repeater stations be simple 

 and involve a minimum of maintenance. With the repeater design 

 as described it is expected that most of the repeaters may be operated 

 on an unattended basis, requiring maintenance visits at infrequent 

 intervals. 



An important factor in this connection is the possibility of supplying 

 current to unattended repeaters over the transmission line itself. The 

 coaxial line is well adapted to transmit 60-cycle current to re- 

 peaters without extreme losses and without hazard. The repeaters 

 with regulating arrangements as built experimentally for a million- 

 cycle system are designed to use 60-cycle current, which in this case 

 appears to have the usual advantages over d.-c. supply. One repeater 

 requires a supply of about 150 watts. The number of repeaters which 

 can be supplied with current transmitted over the line from any one 

 point depends upon the voltage limitation which may be imposed on 

 the circuit from considerations of safety. 



For a repeater of the type described with current supplied over the 

 line, only a very modest housing arrangement will be required. For 

 the great majority of stations, it appears possible to accommodate the 

 repeaters in weatherproof containers mounted on poles, in small huts, 

 or in manholes. 



