File:Bell telephone magazine (1922) (14733271156).jpg

Identifier: belltelephonevol3132mag00amerrich (find matches)
Title: Bell telephone magazine
Year: 1922 (1920s)
Authors: American Telephone and Telegraph Company American Telephone and Telegraph Company. Information Dept
Subjects: Telephone
Publisher: (New York, American Telephone and Telegraph Co., etc.)
Contributing Library: Prelinger Library
Digitizing Sponsor: Internet Archive

View Book Page: Book Viewer
About This Book: Catalog Entry
View All Images: All Images From Book
Click here to view book online to see this illustration in context in a browseable online version of this book.

Text Appearing Before Image:
e to havea good reason to calT 230 Bell Telephone Magazine WINTER able to do is to keep the cost of thecircuits from going up as rapidly asprices in general have risen. But if the problems are great, thestakes are even greater, just becausethere are so many calls of this variety.Lets look at this matter of lengthversus dollars more closely. The Shorter the Tougher In order to get the right perspectiveon this short-haul problem and howwe believe it will be solved eventually,I am going to have to get close—but not dangerously so, I hope—tothe cage marked Danger—dbs—donot disturb or attempt to feed.And in doing so, I am going to goback to a couple of fundamentals. In the days before electronics, itwas generally true that the longerthe circuit the more it cost per mile,if it were to give the same perform-ance. To illustrate: a circuit, say,lo miles long had to have wires of agiven size to produce not over a de-sired number of dbs in the lo miles.Now if we wanted to go 20 miles, we
Text Appearing After Image:
obviously would have to have wirestwice as long but, in addition, if wewanted to have the same number ofDBS as in the 10 mile circuit, the wireswould have to be about twice as big.Thus, to keep the same performanceat twice the length, we had to usefour times as much copper (twice asmuch per mile times twice as manymiles). In the electronic era the reverse Isin general true for everything butthe very short circuits, say, up to fiveor ten miles. That is, the longer thecircuit the less it costs per mile forequal performance. And this re-quires a little explaining. In this era, the transmission en-gineer no longer uses the brute forcemethod of putting more copper in toget DBS out. He uses electronicamplifying and carrier gear. Thus: 1. For the circuits of moderatelength he can use as small wires ashe wishes and can offset the dbsthus added by taking out dbs bymeans of amplifiers. 2. For the longer circuits, he usescarrier,* which divides the cost of the base plant—the pole lines,the cab

Note About Images