68 BELL SYSTEM TECHNICAL JOURNAL 



systems depend on wave-length and transmission conditions. Under 

 favorable conditions the improvement effected at each end is approxi- 

 mately equivalent to a transmitted power increase of 100 times. The 

 most useful wave-lengths for this service have proved to be in the 

 vicinity of 16 meters, although wave-lengths of about 22 and H meters 

 are also provided to increase the amount of time these circuits are 

 satisfactory for service because at certain seasons and times of day 

 they are more effective than the 16 meters wave-length. 



Service over the transatlantic facilities is carried on from 6.30 in 

 the morning to 10.00 at night in New York, corresponding to 11.30 

 in the morning and 3.00 A. M. London. During the winter months 

 the long waves give nearly continuous service over this period. Under 

 summer conditions considerable difficulty is frequently experienced 

 in maintaining the long waves during the afternoon period in New 

 York, corresponding to the evening period in London. At these 

 times, however, the short waves are usually effective. 



The projected transatlantic telephone cable will use new magnetic 

 loading materials and new insulating compounds for submarine cables 

 recently developed by the Bell Telephone Laboratories. It will have 

 at least one intermediate repeater point at Newfoundland. A circuit 

 of this kind, differing radically from radio circuit in its characteristics 

 will add both to the message capacity and to the reliability of the 

 transatlantic service. 



Connections to South America 



Figure 53 indicates a short-wave radiotelephone circuit from New 

 York to South America which, it is expected, will be in service early 

 in 1930. The South American transmitting and receiving stations, 

 which will be in the vicinity of Buenos Aires, will be owned and oper- 

 ated by the companies who operate the local telephone service in 

 Buenos Aires and the wire lines extending to other points in South 

 America. 



Special Services 

 Telegraph Circuits 



While the Bell System handles practically no commercial telegraph 

 message business, it plays an important part in meeting the communi- 

 cation needs of the United States by furnishing a large mileage of 

 telegraph circuits for the private use of individuals and institutions, 

 and for the use of governmental departments. Over two million 

 kilometers of such circuits are now in use. One-third of this amount 

 is used by newspapers and press associations. The greater part of 



