608 



Popular Science Monthly 



have learned all the letters, and are able to 

 call them to mind easily, try to get some 

 trained wireless operator to call on you and 

 send over your buzzer line. If you will 

 send the alphabet through from A to Z 

 several times, and follow it with the 



A rotating disk with notches in its circum- 

 ference to make the -dots, dashes and spaces 



classical sentence, "The quick brown fox 

 jumps over the lazy dog" (which contains 

 every letter of the alphabet) , he will soon be 

 able to judge wherein your sending is in 

 need of improvement, and to correct you. 

 Be sure to pay strict attention to his sugges- 

 tions, for they will probably be valuable to 

 you. 



After your sending has been passed on by 

 a seasoned operator, try to have him send 

 for you a little while. Ask him to send so 

 slowly that you can get every letter, and 

 pay close attention to the smoothness with 

 which he forms the dot and dash combina- 

 tions. If you can, have him take the key 

 at the station at one end of your line, and go 

 to the other end yourself. By exchanging a 

 few messages with him, and listening 

 sharply to his style of Morse sending, as 

 well as by having him note the imperfec- 

 tions in your sending, you can do a great 

 deal toward perfecting yourself in the art of 

 telegraphing. 



Three- Station Lines 



Occasionally it is possible to run the 

 buzzer telegraph . line by the home of a 

 wireless operator, and to install a third 

 station in his house. If he is willing to help 

 you out, he will send from a newspaper for 

 half an hour or so each evening, and then 

 let you send to him for ten or fifteen 

 minutes. This sort of practice will be 

 exceedingly valuable, if it can be arranged. 

 Sometimes half a dozen students wish to 

 get on the same buzzer-telegraph wire and 

 to practice together. Fig. 8 shows how 



three stations may be connected with the 

 same line. wire, and identical station-units 

 may be added almost without limit. 

 Pressing the key K at any one of them will 

 operate its buzzer Z, by reason of closing 

 the circuit from the battery B through the 

 buzzer magnet windings, and the signal- 

 tone of the buzzer will be reproduced in the 

 telephones T at all of the stations. It is 

 only necessary to keep the insulation of the 

 line wire L L L fairly good, so as to prevent 

 leakage, and to make a good connection to 

 earth through a scraped water, gas or 

 steam pipe at each of the points marked £ 

 in the diagram Fig. 8. The higher the 

 resistance of the telephones, up to several 

 thousand ohms, and the more powerful the 

 buzzers and batteries, the better the line 

 will work when a comparatively large num- 

 ber of stations are added to it. If the 

 signals in any of the telephones are found to 

 be too loud, their terminals may be shunted 

 by a resistance of fifty or a hundred ohms or 

 thereabouts (the best amount being found 

 by trial), as shown in Fig. 5 (last month's 

 article). 



It is not always easy or even possible to 

 get a wireless operator to visit your home 

 and try out your buzzer line; if you find 

 this difficult, it is a good plan to call at 

 some local telegraph office and to try to 

 pick up a few pointers from the operators 

 there. Although the line telegraphers in 

 the United States use the American Morse 

 code, which differs as to some of its charac- 

 ters from the International Morse used in 

 wireless, the two systems have much in 

 common and a few words of criticism from a 

 skilled line operator will often be of 

 inestimable value to the student. 



Copying Perfect Signals 

 Such a plan, however, does not give the 



Another type of automatic sender in which a 

 tape is used having holes in it for the letters 



student any opportunity to listen to and 

 copy perfectly formed Morse characters at 

 gradually increasing speeds. The two- 



