194 



THE BELL SYSTEM TECHNICAL JOURNAL, JANUARY 1951 



in an A.I.E.E. papei^° by S. G. Hale, A. L. Quinlan, and J. E. Ranges, 

 "Recent Improvements in Loading Apparatus For Telephone Cables." 



The various relative transmission-impairments, above mentioned, were 

 accepted in advance as being tolerable from the service standpoint under 

 war conditions, considermg the types of circuits required and their probable 

 relatively short lengths. At that time it was thought possible that better 

 loading units, not necessarily as good as the M-type units, might be war- 

 ranted in the post-war period. Meanwhile, the service experience with the 



Fig. 14 — Potting assembly methods — small complements of M-type and MF-type 

 loading units. Note use of lead sleeve casing for MF type units, and relatively large welded- 

 steel casing for M-type units. 



small loading units has been reasonably satisfactory, largely because of the 

 easing-up of performance requirements that is resulting from the restriction 

 of toll cable loading to short-haul facilities. These seldom have more than 

 two repeater sections, in consequence of the economic competition offered 

 by present standard and proposed new, cheaper, carrier systems on non- 

 loaded cable. Under these circumstances, the cost of developing better 

 loading units which would probably increase the loading costs would be 

 hard to prove in. Thus, the MF-type war-emergency loading units became 

 post-war loading standards. 



