. Practical wireless telegraphy; a complete text book for students of radio communication . l advantage of this gap is that it prevents the oscillations in theaerial circuit being retransferred to the closed circuit resulting in more efficientradiation; in other words the quenching is reliable. The one-half kilowatt sets of the American Marconi Company are fitted with APPLIANCES FOR A RADIO TRANSMITTER. 105 synchronous dischargers which are practically a duplicate of the larger size gapssuch as furnished with the 2 K. W. sets. (d) The construction of the quenched spark discharger is shown in F
. Practical wireless telegraphy; a complete text book for students of radio communication . l advantage of this gap is that it prevents the oscillations in theaerial circuit being retransferred to the closed circuit resulting in more efficientradiation; in other words the quenching is reliable. The one-half kilowatt sets of the American Marconi Company are fitted with APPLIANCES FOR A RADIO TRANSMITTER. 105 synchronous dischargers which are practically a duplicate of the larger size gapssuch as furnished with the 2 K. W. sets. (d) The construction of the quenched spark discharger is shown in Fig. 117where a number of heavy copper plates separated by fiber insulating washersmicanite, or other insulating material, are placed in an iron rack and compressedby means of a pressure bolt. The thickness of the washers is chosen so that thespace between the sparking surfaces of a single set of plates does not exceed .01inch. A groove is cut in each plate over which the inside edge of the washer prevents the spark discharging at the very edge of the washer which would COPPER. Fig. 117—Modern Quenched Spark Discharger with Motor Blower. soon cause a short circuit. The insulating washers are specially treated so thatthe discharge surface is airtight. This not only aids in quenching out the primaryoscillations, but gives a noiseless discharge as well. It will be noted from the photograph, that the gap is cooled by a small motor-drivenblower mounted on the base which forces a draught of air through the base of the rackagainst the cooling flanges of the plates. Since the quenched discharger had been found to be effective with comparatively lowvoltages, the potential of the transformer secondary rarely exceeds 15,000 volts, pressuresas low as 6,000 volts being frequently employed. Approximately 1,200 volts are requiredfor each gap and the number that will be used in any case depends upon the voltage of thetransformer. The great advantage of the quenched gap lies in its
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Keywords: ., bookcentury1900, bookdecade1910, booksubjecttelegra, bookyear1917
