. Practical wireless telegraphy; a complete text book for students of radio communication . ^-^<^ Fig. 213—Another Method for exciting Oscillationsin an Antenna by Buzzer. (1) The natural or fundamental wave length of the aerial;(2).The wave length of the closed oscillation circuit;(3) The wave length of the radiated wave. After the open and closed circuits have been coupled, we must determine: 192 PRACTICAL WIRELESS Fig. 214—Buzzer Excitation Circuit InductivelyCoupled to an Aerial. (1) Purity and sharpness of the radiated wave; (2) The decrement of damping. (o) Measurement of
. Practical wireless telegraphy; a complete text book for students of radio communication . ^-^<^ Fig. 213—Another Method for exciting Oscillationsin an Antenna by Buzzer. (1) The natural or fundamental wave length of the aerial;(2).The wave length of the closed oscillation circuit;(3) The wave length of the radiated wave. After the open and closed circuits have been coupled, we must determine: 192 PRACTICAL WIRELESS Fig. 214—Buzzer Excitation Circuit InductivelyCoupled to an Aerial. (1) Purity and sharpness of the radiated wave; (2) The decrement of damping. (o) Measurement of the Open Circuit. One method of setting the aerial intoexcitation and measuring the natural or fundamental wave length was shown inFig. 211, but there are several alternative methods by which the antenna may beset into oscillation. In the method shown in the diagram, Fig. 212, a condenser C of one- microfarad capacity is connected in series with the aerial andalso across the vibrator of a buzzer B-1energized by the battery B-2. The counterE. M. F. of the buzzer windings places anelectrostatic charge on the aerial which dis-charges at practically its natural capacity of C being very large comparedto that of the aerial, the wave length of thesystem is not appreciably altered. With the buzzer adjusted for clear tones,the wavemeter, fitted with a crystal rectifier,is placed in inductive relation to the earthlead
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Keywords: ., bookcentury1900, bookdecade1910, booksubjecttelegra, bookyear1917
