. Radio for everybody; being a popular guide to practical radio-phone reception and transmission and to the dot-and-dash reception and transmission of the radio telegraph, for the layman who wants to apply radio for his pleasure and profit without going into the special theories and the intricacies of the art . gineers asto the traffic-carrying capacity of the ether for long-dis-tance communication. The figures for long-distance tele-graphy can be at least roughly estimated without seriousdifficulty. We shall assume continuous wave transmis-sion, with an appropriate form of key modulation inse
. Radio for everybody; being a popular guide to practical radio-phone reception and transmission and to the dot-and-dash reception and transmission of the radio telegraph, for the layman who wants to apply radio for his pleasure and profit without going into the special theories and the intricacies of the art . gineers asto the traffic-carrying capacity of the ether for long-dis-tance communication. The figures for long-distance tele-graphy can be at least roughly estimated without seriousdifficulty. We shall assume continuous wave transmis-sion, with an appropriate form of key modulation insending the dots and dashes, and without any tone modula-tion whatever. Under these conditions, and taking intoaccount both side bands produced as the result of actualtransmission, it has been found that a speed of 100 words(or 500 letters) per minute corresponds to the occupa-tion of a band of frequencies in the ether roughly 100cycles wide. This is on the basis that the radio-fre-quency generator maintains its frequency constant duringtransmission. We shall also assume that the receiver issufficiently selective to exclude all signals on frequenciesoutside of this 100 cycle band. Under these conditions,we may say roughly that on each cycle per second ofavailable ether frequencies we can transmit one word. The power plant and station building of the Radio Central wirelessstation. In the foreground are the sprays and cooling basin forcooling and condensing purposes, forming part of the power plant operation. 276 RADIO FOR EVERYBODY per minute. Assuming further that long-distance trafficwill be handled in the range of wave lengths between6,000 meters and 40,000 meters, a reasonable assump-tion on the basis of present-day practice—and also aconservative one—we shall have available a band of etherfrequencies of from 50,000 to 7,500 cycles per second,or 42,500 cycles in all. According, we can ultimatelytransmit at least 42,500 words per minute via radio overlong distances, or no l
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