. Practical wireless telegraphy; a complete text book for students of radio communication . y ofthis transmitter. The second disadvantageis that the insulation of the aerial is sub-jected to an abnormal strain caused by thehigh voltage necessary and by the low fre-quency current of the induction coil beingsuperposed on the radio-frequent oscilla-tions. The oscillations in the antenna circuit ofthe plain aerial transmitter will be dampedout less rapidly if fair amounts of induct-ance are inserted at the base as at L, Under these conditions, the decrementof the oscillations may compare
. Practical wireless telegraphy; a complete text book for students of radio communication . y ofthis transmitter. The second disadvantageis that the insulation of the aerial is sub-jected to an abnormal strain caused by thehigh voltage necessary and by the low fre-quency current of the induction coil beingsuperposed on the radio-frequent oscilla-tions. The oscillations in the antenna circuit ofthe plain aerial transmitter will be dampedout less rapidly if fair amounts of induct-ance are inserted at the base as at L, Under these conditions, the decrementof the oscillations may compare favorablywith modern methods of excitation. Indirect methods of antenna excitation are shown in Figures 106 107 and 108. Theprincipal advantage of these methods of coupling lies m the fact that the closed rcuit con-denser acts as a reservoir of energy and since the capacity of the condenser m the closedoscillation circuit is generally several times that of the capacity of the aerial, Jt Permits theclosed circuit to use large amounts of power for the same wave length, spark frequency and. W I Fig. 106—Inductively Coupled Transmitter. 94 PRACTICAL WIRELESS TELEGRAPHY. voltage which results in the production of more powerful oscillation. Then by proper adjust-,ment of coupling, these oscillations may be transferred to the antenna systems at a certainrate and radiated in the form of electro-magnetic waves. inductive coupling of the open and closed oscillation circuits is shown in thediagram, Fig. 106. The spark gap S is nov^r placed in the closed oscillationcircuit, the oscillations generated in the latter are transferred to the antennathrough the oscillation transformer, L, L-1. When the condenser discharges -through L, the lines of force cut through L^,setting up in the aerial circuit oscillations of similar frequency provided the aerialcircuit is carefully tuned to the closed circuit. Winding L is seen to serve thedouble purpose of governing the frequency of the oscillations i
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Keywords: ., bookcentury1900, bookdecade1910, booksubjecttelegra, bookyear1917
