. Practical wireless telegraphy; a complete text book for students of radio communication . resulting oscillations of coupledcircuits may be shown by the dia-gram of Fig. 109, where two groups ofoscillations in the closed and open cir-cuits are represented. It will be notedthat the oscillations in the closed cir-cuit have maximum amplitude whenthose in the open circuit have minimumamplitude, and vice versa. In the sense of a second of time the two sets of oscillations takeplace simultaneously, but in the sense of a fraction of a second they do not reach theirmaximum amplitude simultan
. Practical wireless telegraphy; a complete text book for students of radio communication . resulting oscillations of coupledcircuits may be shown by the dia-gram of Fig. 109, where two groups ofoscillations in the closed and open cir-cuits are represented. It will be notedthat the oscillations in the closed cir-cuit have maximum amplitude whenthose in the open circuit have minimumamplitude, and vice versa. In the sense of a second of time the two sets of oscillations takeplace simultaneously, but in the sense of a fraction of a second they do not reach theirmaximum amplitude simultaneously. When the antenna oscillates at two distinct frequencies, two waves of different length areset into motion. This is an undesirable condition, (1) because the receiving apparatus gen-erally can be tuned only to one of the radiated waves, the energy of the other being lost;(2) a needless amount of interference is caused thereby to the operation of other radiostations. The true coefficient of coupling between two circuits of this character is determinedby the following formula: MK =. Fig. 109.—Showinp: Complex Oscillations in Im-properly Adjusteci Transmitter. where L, and L„ = self-inductance of the primary and secondary circuits respectively, M = coefficient of is the custom to determine the coupling from actual measurement of the radiatedwaves, or ^is is coupling by electrostatic induction. Direct or conductive electrostatic induction may alsobe used. 96 PRACTICAL WIRELESS TELEGRAPHY. Vs —Vi Kr X^a + \h Where Xs = longer wave,Xi = shorter if X equals the wave length to which the primary and secondary circuits are ad-justed independently, then Xa = Xs V 1 + K Xi =XaV 1 — K In other words, if the value of the coupling K is known, the two wave lengths canbe calculated before actual measurement. When the primary winding of the oscillation transformer is placed close to the second-ary winding, perhaps partially telescoped into it, the set is said
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Keywords: ., bookcentury1900, bookdecade1910, booksubjecttelegra, bookyear1917
