. Practical wireless telegraphy; a complete text book for students of radio communication . t of the wavemeter;Xl = wave length 3 per cent to 5 per cent, above resonance;Xl = wave length 3 per cent, to 5 per cent, below resonance;1 ^ current corresponding to wave lengths above and below resonance. The decrement of the wavemeter must, of course, be subtracted to obtain the value of 5i. Direct reading decremeters, such as the Kolster* decremeter (U. S. Bureau of Standards) are in use. In this instrument, a dial geared to the movable plates of the variable condenser is fitted with a scale ofBi de
. Practical wireless telegraphy; a complete text book for students of radio communication . t of the wavemeter;Xl = wave length 3 per cent to 5 per cent, above resonance;Xl = wave length 3 per cent, to 5 per cent, below resonance;1 ^ current corresponding to wave lengths above and below resonance. The decrement of the wavemeter must, of course, be subtracted to obtain the value of 5i. Direct reading decremeters, such as the Kolster* decremeter (U. S. Bureau of Standards) are in use. In this instrument, a dial geared to the movable plates of the variable condenser is fitted with a scale ofBi decrements and when th? reading of the wattmeterat a given point offresonance is one-halfof that obtained at reson-ance, the combined decre-ment of the decremeterand the circuit undermeasurement is obtainedby first setting the decre-ment scale at zero (whenone-half resonance cur-rent is obtained) afterwhich the decrement dialis clamped to the movableplates of the variablecondenser and the latterturned to resonance andto a point beyond wherethe reading of the watt-meter again falls to one-. Fig. 223—Wavemeter as a Source of Radio Frequency Oscillations. Bureau of Standards publication No. 235 describes the Kolster Decremeter in detail. PRACTICAL RADIO MEASUREMENTS. 205 half that at resonance. The decrement dial will then indicate the combined decrement of thecircuit under measurement and that of the decremeter. A photograph of the Marconi decremeter appears in Fig. 220 and the Kolster decremeterin Figs. 221 and 222. The latter is used by all U. S. Government radio inspectors. 171. Wavemeter as a Source of High Frequency Oscillations.—A wave-meter excited by an ordinary vibrating buzzer may be used to generate feebleoscillations of radio-frequency for measuring purposes. The complete diagram for the apparatus is shown in Fig. 223. The circuit from thebattery to the buzzer B-1 is completed through the coil of the wavemeter L. To eliminatesparking at the vibrator, the windings (o
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Keywords: ., bookcentury1900, bookdecade1910, booksubjecttelegra, bookyear1917
