Abstracts of Technical Articles by Bell System Authors 



A Modification of Halleii's Solution of the Antenna Problem} M. C. 

 Gray. An alternative formula for the input impedance of a cylindrical 

 antenna is derived from Hallen's integral equation. It is shown that the 

 introduction of a variable parameter Z{z) in place of Hallen's S2 = log 

 (4/-/a^) modiiies the numerical results considerably, and leads to much 

 better agreement with experimental evidence. 



Motor Systems for Motion Picture Production? A. L. Holcomb. The 

 various types of motor systems and speed controls used in motion picture 

 production are reviewed, evaluated, and the basic theory of operation 

 described. 



Motor drive systems are a fairly simple but important element in the 

 production of motion pictures, but to many people who do not have direct 

 contact with this phase of activities, the number of systems in use and their 

 peculiarities are very confusing. Data on most of the different types of 

 motors and motor systems in use have been published, but in different places 

 and at different times so that no comprehensive reference exists. This 

 paper is not intended as information on new developments or as a technical 

 study, but rather as a review of all the major systems with an indication of 

 their fields of greatest usefulness and with comments on both their desirable 

 and undesirable features. 



A Dial Switching System for Toll Calls} Howard L. Hosford. At 

 Philadelphia, on the night of August 21st and the early morning hours of 

 August 22, 1943, the cutover of the new #4 System was no mere episode; 

 it was one of the milestones of telephone history. IntertoU dialing in itself 

 is not new but this joint project of the Bell Telephone Company of Penn- 

 sylvania and the Long Lines Department is especially significant as it has 

 been designed so as to extend the field of toll dialing by the operators to 

 include the largest cities and joins together various types of dialing equip- 

 ment. In its scope this project includes many points in an area reaching 

 from Richmond, Va. to New York City and from Harrisburg, Pa. to At- 

 lantic City, N. J. 



From a traffic standpoint the # 4 toll switching system actually comprises 



^Jour. Applied Physics, January 1944. 

 ^Joiir. S. M. P. E., January 1944. 

 ^Bell Tel. Mag.. Winter 1943-44. 



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