Page:Popular Science Monthly Volume 91.djvu/809

 Wireless Work in Wartime

IV. — The complete forms for sending official messages By John L. Hogan, Jr.

��THE complete international Morse code, including numerals and the more important punctuation marks, was given in preceding articles of this series. The second article, appearing in the September issue, explained the simpler methods of calling and answering by radio, as well as the plan usually followed in acknowledging the receipt of radiograms and in securing repetition of words or por- tions of messages not correctly received. The complete forms for sending official messages have not been discussed, however. Radio telegraphic transmission is for the most part carried on according to a series of regulations agreed upon at the London International Radiotelegraphic Convention of 1912. This convention and the set of rules there formulated are given in full in a pamphlet entitled "Radio Communication Laws of the United States," which may be secured for fifteen cents from the Superin-

��it is perhaps best for the student to give his attention to the methods approved by the Director of Naval Communications. These are given very fully in a "Handbook of Regulations" of the U. S. Naval Radio Service which was issued about four years ago and which is brought up to date by means of supplements issued from time to time. Additional information may be found in the Navy's "Commercial Traffic Regulations" of 19 15. The scheme used is an elaboration of the London Convention and agrees with its rulings.

In the first place, a station wishing to communicate with another, first sends out a radio call by making the attention signal (dash-dot-dash-dot-dash), the call letters of the desired station three times (KUR KUR KUR, for example), the word "de" (meaning "from"), and then its own call letters three times (for example: KSW KSW KSW). This is usually followed by

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��FIG. 13 A station wishing to communicate with another first sends out a radio call by making the atten- tion signal, call letters of the desired station three times, then its own letters three times and a cross

��tendent of Documents at Washington, D. C. Every student of radio should get a copy of this booklet, since it contains, in addition to the report of the convention, much valuable information with regard to the licensing of radio stations, radio operators, the Department of Commerce Districts for the supervision of radiotelegraphy, etc.

Although the London Convention is very specific as to certain of its rulings, it does not give in detail the methods to be fol- lowed in transmitting messages of various types. Each radio organization has certain peculiarities in this respect. One company will habitually use a system of. symbols which are not entirely adopted by other radio administrations; but, fortunately, these variations are usually not serious enough to cause much difficulty.

Inasmuch as the Navy Department is in entire charge of radio work during wartime,

��the finish signal (dot-dash-dot-dash-dot), although such procedure is not strictly official in the call. The station called, on hearing the signals, replies by giving the attention signal, the call letters of the call- ing station three times, the word "de", its own call letters three times, and, if ready to receive, the "Go ahead" signal ("K"). If the station is not ready to re- ceive, instead of sending "Go ahead," the operator signals "Wait" (dot-dash-dot-dot- dot) or some one of the official abbrevia- tions such as QRX (which means "Stand by; I will call you when required") or QRW (which means "I am busy; please do not interfere"). The list of abbrevia- tions is given in full on page 46 of the "Radio Communication Laws of the U. S." above referred to, and forms a very im- portant supplement to Article XXII of the Convention regulations.

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