File:Bell telephone magazine (1922) (14753524091).jpg

Identifier: belltelephonemag19amerrich (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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Text Appearing Before Image:
_: CJ o o 1 w SJaqaTnN :;odsuns SAi^^epy 1 i9^0 Sun Spots and Telephone Service 187 80 60 40 20 ^ 53 O 0) u (20 1.20 100 1.00 Earth CurrentVariations
Text Appearing After Image:
Years FIG. 2 Chart showing the annual mean of relative sun spot numbers, of magnetic activity,and of earth current variations * relative transmission disturbance overshort wave radio channels for the pe-riod from 1929 to 1939, inclusive, islikewise shown. The correspondencebetween the magnetic activity and rel-ative radio disturbances, on the onehand, and the relative sun spot num-bers, on the other, is very evident.All show marked maxima at intervalsof about 11 years. The question asto why, in the first place, the solaractivity should vary in these 11-yearcycles is still unanswered. Inciden-tally, it is interesting to note fromFigure 1 that there was a definitepeak in magnetic activity in 1859, the year when the severe effects on tele-graph circuits previously mentionedwere experienced. Figure 2 illus-trates the same general relationshipbetween the annual mean sun spotnumbers and annual mean magneticactivity, and, in addition, indicatesfurther their relationship to earth cur-rent var

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