Radio Broadcast (May-Oct 1922)

3i8 Radio Broadcast to register the effects of disturbances of but one definite frequency, the lack of perfection of our receiving equipment as yet makes this impossible. To avoid interference between transmitting stations it is obvious, then, that the frequency of the disturbances whicl. they create must differ to a sufficient extent to offset the short-comings of the available apparatus and methods. The very best that we are able to hope for now is a difference in frequency, for adjacent transmitting stations, of at least 10,000 cycles. This means that within a given small area it would only be possible to erect a comparatively small number of stations, and at the same time avoid interference. But, if stations are separated sufficiently, and if they are limited in their range of transmission, two or several may operate on the same wave length without producing interference at the receiving station. These things have all been taken into consideration in the division of available wavelength bands among the various classes of service. radio's most important service RADIO telegraphy quite naturally found its first application in providing communication between points excluded from the use of other methods. First of all came communication between ships at sea and between ships and shore. Communication of this class is a very important one, since it insures the safety of both life and property at sea. Communication of this class is still considered as the most important use to which radio telegraphy and telephony may be put, and now that we have discovered the wonderful potentialities in connection with the broadcasting of vital news information, educational matter, entertainment, etc., it is the consensus of opinion, of American radio men at least, , that radio broadcasting ranks second in order ' of importance. Perhaps that class which ranks third in this list is intercommunication among amateurs, for neither our Army or our Navy can forget the importance of a personnel trained in modern signal methods during wartime. It is doubtful whether enough money could be appropriated by our Government to train such a vast body of communication men as those amateurs who train themselves in their fascinating pursuit of radio telegraphy, it has been recommended by this Conference of experts that the status of amateurs be es tablished by law, and that certain wave bands be allotted to them and specified in the law. And, so good has been the impression which amateurs and amateur organizations have made upon this committee that it has also been recommended that amateurs "police" themselves, — that they be a self-governing body with regard to operation, violations, etc. HOW THE ETHER IS DIVIDED THERE are many other classes of service, too, and they all have been given proper consideration. Intercontinental radio telegraphy service has been allotted its band of waves; naval service, army service, aircraft service, radio compass service, radio beacons, city and state public safety service, technical and training schools, and, in certain cases, private radio stations have all been taken care of. Most of the intercontinental service requires the use of very high power. High power stations best fit themselves to the lower frequencies, i. e., long wavelengths. Low power transmitters such as those used by amateurs, and such as those used in broadcasting and for ship to shore work, adapt themselves to the shorter wave length. Some idea as to how these wavelengths have been divided is given in the table showing allocation of wave bands for radio telephony. WHAT THE TECHNICAL TERMS MEAN FOR an understanding of this table, some of the terms used in it are defined. "Broadcasting" is that type of transmission which is intended for consumption by an unlimited number of receiving stations, no charge being made for the service. This includes service broadcasted by departments of the Federal Government (Government broadcasting) ; the dissemination by radio of educational and informational service b\' public and state institutions, universities, etc. (public broadcasting) ; the broadcasting without charge of news, entertainment, and other service by the owner of a station, such as a newspaper, or other private or public organization (private broadcasting) ; and broadcasting by a transmitting station of a public service corporation where a charge is made for the use of the station (toll broadcasting). By "fixed" service radio telephony is meant radio telephone service between two fixed points.