. Practical wireless telegraphy; a complete text book for students of radio communication . , primary winding L-2 isconnected in series with the aerial circuitwhich brings the intermediate circuit into use,but the switch, thrown in the opposite direc-tion, disconnects L-2 and connects L-6 inseries with the aerial. 1^6 being woundtightly about the turns of L-S, the open andclosed circuits are closely coupled. This in-creases the damping of the receiving systemand makes the set responsive to waves of dif-ferent length at one set of adjustments, but,of course, does not give the strength of sig-na
. Practical wireless telegraphy; a complete text book for students of radio communication . , primary winding L-2 isconnected in series with the aerial circuitwhich brings the intermediate circuit into use,but the switch, thrown in the opposite direc-tion, disconnects L-2 and connects L-6 inseries with the aerial. 1^6 being woundtightly about the turns of L-S, the open andclosed circuits are closely coupled. This in-creases the damping of the receiving systemand makes the set responsive to waves of dif-ferent length at one set of adjustments, but,of course, does not give the strength of sig-nals that can be obtained by resonant adjust-ments. The position of the switch correspondingto close coupling is marked Stdbi, an ab-breviation for the word standby. The switchis placed in this position when a particularreceiving .station avraits a call from one ofseveral sending stations which are not exactlytuned to the same wave length. In the opposite position, the changeover ,,, ^ ,^ ^ „ , -r^ ,^ switch is marked tune and with the circuits ^^- -STalve^locket CRY5TAL TENSIONADJU5T0R. CONTACTPOINT VALVESOCKET to Fit 144 PRACTICAL WIRELESS TELEGRAPHY. of this connection, sharp resonant adjustments can be obtained. The wave length of theintermediate circuit is increased or decreased by the variable condenser C-2 only and simi-larly the wave length of the secondary or detector circuit, by the condenser C-3. The coupling between the inductances of the intermediate circuit and inductively relatedcoils is varied simultaneously by means of a shaft (and knob) upon which both coils, L-3and L-4, are mounted. The impedance coil R-1 prevents the accumulation of high voltages upon the dielectricof the variable condenser, which may be punctured in case the windings of the tuner shouldcome in direct contact with the high voltage wires of the transmitting apparatus. The American Marconi Company has developed a crystal holder to fit in theFleming valve socket as shown in Fig. 163. The circui
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Keywords: ., bookcentury1900, bookdecade1910, booksubjecttelegra, bookyear1917
