Page:Popular Science Monthly Volume 91.djvu/623

 Wireless Work in Wartime. Ill,

By John L. Hogan, Jr.

��THE two articles of this series which have already been published, in the August and September issues, out- lined the simplest ways to learn the Morse Code used in radio telegraphy and ex- plained a buzzer-telegraph line which could be used for code practice. The cooperation of two. students in the manner indicated makes it possible for both to advance far more quickly than could either one working alone. By placing themselves at the opposite ends of an electrical communica- tion system (the buzzer-telegraph line) and by relying upon it for the interchange of messages and for correction of errors of transmission, both operators learn to de- pend upon their own efforts to signal correctly. It becomes evi- dent at once that clear, uniform for- mation of the Morse dots and dashes is essential to real tele- graphing, since poor sending at once brings its natural consequence of incorrect

��Diagram showing how three stations may be connected with the same line wire and other units may be added as desired

��receiving. The greatest temptation of the novice telegrapher, viz., to send too fast, is quickly shown to be productive of nothing but trouble; to send £0 fast that the words run together, or so fast that incorrect Morse characters are formed, or so fast that the receiving oper- ator cannot put the words down easily and completely, is to show one of the clearest signs of incompetence. The experienced operator suits the speed of his sending to the particular conditions, and never trans- mits the words so fast that the receiving operator cannot "copy" all of them. To adapt one's gait to the man at the other end of the line, be it wire or wireless, is not only common courtesy but has been found by long experience to result in the ac- curate transmission of the greatest num-

��ber of words in any given length of time. Dangei j of Student Practice

Although the buzzer practice line has the advantages indicated above, there is a danger in having no sending to listen to except that of a companion student. Starting from the ground, with no tele- graphic experience, one is likely to make some mistakes even though the greatest care is used. It is most difficult to form the complex characters like "Q" (dash-dash- dot-dash) and "Y" (dash-dot-dash-dash) correctly, and a beginner is always likely to interject an extra dot-space or two. Con- sequently "Q" is made to sound like "M A" (dash-dash, space, dot-dash), and

"Y" seems

line wire very much like "N M." This defect may be no- ticed after the word "YOU" is written out as "NMOU" several times, but the way the student usually cor- rects the fault is by increas- ing the space between "Y" and the next letters. This has the effect of setting off. the "NM" character, but is not a real cure, since the dash-dot-dash-dash of the letter "Y" has not been smoothed out into perfect form.

There are a large number of errors like these which creep into the sending of students, and, occasionally, even into that of experienced operators. They are always dangerous, however, and often lead to serious misunderstandings. Listen to your own sending, and to that of your partner, and try to make sure that each dot, dash and space is formed and timed correctly. You can weed out these troubles yourself by giving the Morse characters keen enough study; but the best plan is to have some experienced operator listen to your trans- mission and criticize it for you. After you

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