AMONG the problems which the rapid and extensive growth of radio communication has presented, is that of keeping the frequencies of all transmitting stations steadily at their assigned values. The success of the various international plans which have been formulated in recent years, particularly for the control of broadcasting, must ultimately depend upon the ability of radio engineers to adjust and maintain a wireless transmitting station at its correct frequency or wave-length. At the present time the primary standards of frequency, which utilise either a tuning fork or a piezo-electric crystal, are amongst the most accurate of our physical standards. With the aid of suitable equipment, there is no difficulty in maintaining and using an accuracy well within one part in a million, while the frequency standards of different countries are in substantial agreement to within a few parts in ten million. Similar types of crystal or tuning fork oscillators can be employed to control the frequency of transmitting stations of appreciable power, by the aid of somewhat elaborate power-amplifying and, if necessary, frequency-multiplying equipment. This arrangement admirably serves the purpose of those stations operating on a single wave-length, and is used with conspicuous success in broadcasting stations and those used for long-distance telegraphic and telephonic communication.
About this article