Identifier: belltelephonemag11amerrich (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

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e connected serially in the line at intervalsof about 2y2 miles. When these loading coils were first in-stalled, transmission was materially improved and very favor-able comments were received from the users of the service.Then, lightning and atmospheric moisture began to causetrouble. The troubles caused by lightning were soon over-come, but the moisture resulted in serious leakage difficulties,which gradually became worse as more dirt collected at theleakage points. These could not be overcome without radicalchanges, so that the loading coils were removed from the twoNew York-Chicago circuits in 1903. Work was continued onthe loading method and, as a result, about 1904 loading beganto be applied as a regular engineering proposition to lightergauge open wires, particularly wires 104 mils in diameter, forwhich circuits the leakage effects were relatively less serious.The loading coils were spaced about 8 miles apart, whichspacing remained standard for all future open-wire loading. 302
Text Appearing After Image:
Alexander Graham Bell at the Opening of the First New York-Chicago Telephone Line. NEW YORK-CHICAGO TELEPHONE CIRCUITS While none of these loaded 104-mil circuits went into serviceas direct New York-Chicago circuits, some were provided asway circuits which were no doubt connected together from timeto time to handle New York-Chicago business. At about the same time that this early work on loading wasin progress, other work was also in progress on developing thephantoming method. In this method balanced transform-ers are connected to the terminals of two similar circuits con-stituting a phantom group. By making connections to themid-points of the line windings of these transformers, an addi-tional circuit called a phantom is obtained. Thus a 50per cent increase in the number of circuits is obtained withoutstringing additional wires. After overcoming various troubles,not the least of which was the tendency of the circuits to cross-talk unduly into each other, this phantoming method becam

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