Page:Popular Science Monthly Volume 91.djvu/334

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��the study of each promotes progress in the other two; consequently, all three should

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be carried along together. The first two can be studied easily without assistance; but practice in sound reading requires either a companion student or a skilled telegrapher with whom to practice sending and receiving messages, or else an auto- matic sending machine. Probably the most interesting, and certainly one of the most effective, ways to learn the code is to practice it with another student of about equal ability. Thus there is the incentive of competition, and, from the very first work, the satisfaction of actually com- municating with another person through the vehicle of the Morse code. The only difficulty N A

in pursuing this two-student ffT l H 1 1 HBB method lies in the danger of falling into improper habits of sending (e. g., incorrect spacing); but this can be corrected by getting the occasional criti- cisms of a skilled operator.

��be done. The only way to get this rapidity of translation from written letters to Morse letters is by continued practice.

In Fig. i is reproduced the most im- portant part of the code, i. e., the symbols which represent the letters of the English alphabet and the period. With these twenty-seven characters in mind, any message can be transmitted. Numerals and punctuation marks other than the period may be spelled out by name, so that for the first work it is only necessary to memorize these. It will be noted that the letter chart of Fig. i is different from that usually used for showing the Morse code, in that the dots and dashes are plotted on square-section ruling. This shows at once the time allowance which should be made for each dot, space and dash, since each small square represents the time of a "dot-element." This dot-element is ab6ut one-twentieth of a second long in moder- ately fast sending, and is the length of time the current is turned on to form a dot. It is equal to the length of time the current is allowed to remain turned off to form a space between dots and dashes within the same letter. It is one-third of the time the current is turned on to form a* dash.

Subdividing the Alphabet

In memorizing the code it is best to take up the letters in groups. Several modes of division are practicable, but the best seems to be that illustrated in Fig. 2. Here the characters are divided into four classes, according to whether they are formed from one, two, three or four signals

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��Memorizing the Code

The first thing, then, is to memorize the code itself. Without the ability to call to mind instantaneously the dot-and-dash symbol corresponding to each letter it is impossible to operate effectively. One must be able to recall the Morse equivalent of any character without any mental effort — the process must be automatic or sub- conscious before satisfactory sending can

��FIG.3 A time layout of normal spacings, but for the sake of clearness the space between words and letters should be slightly exaggerated

(dots or dashes). The simplest characters are E and T, which comprise a single dot and single dash respectively. These are very easy to remember, so that one may proceed at on^e to the two-signal letters I, M, A and N. It will be noted that the left hand part ot the chart is devoted to the letters in each group which begin with a dot, while the right hand part shows those commenci.ig with a dash. Wherever feasible to do so, letters which are the reverse of each other are arranged side by side, — for instance, A is dot-dash, and

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