. Practical wireless telegraphy; a complete text book for students of radio communication . nc-tions best in ^ thecircuits of the Mar-coni Multiple Tun-er (English Mar-coni Company) inFigs. 168 and general, thecircuits of thistuner appear simi-lar to that of thevalve tuner, but thesecondary windingfor the magneticr ^ , . , detector has very tew turns as compared with the secondary of the valve tuner. The magneticdetector has low resistance compared with crystal detectors and, in consequence,the stopping condenser of the usual detector circuit becomes an active element ofthe closed oscil
. Practical wireless telegraphy; a complete text book for students of radio communication . nc-tions best in ^ thecircuits of the Mar-coni Multiple Tun-er (English Mar-coni Company) inFigs. 168 and general, thecircuits of thistuner appear simi-lar to that of thevalve tuner, but thesecondary windingfor the magneticr ^ , . , detector has very tew turns as compared with the secondary of the valve tuner. The magneticdetector has low resistance compared with crystal detectors and, in consequence,the stopping condenser of the usual detector circuit becomes an active element ofthe closed oscillation circuit and must therefore be of variable capacity. In fact,placing the detector in series with the secondary circuit not only calls for a wind-ing of low inductance but one of low resistance as well. Hence the secondary coilis usually wound with rather coarse wire, such as No. 18 or No. 20 B. and S , 1 IN SERIES A = SOTO ISO METERj C i • Ci Ci c. C IN SERIES WITH AERIAL C. ACROSS INIERMEDIATE CIRCOIT C. IN SEWES WITH MAGMETIC DETECTOFl Fig. 167a—Marconi Multiple Fig. 168—Fundamental Circuit Marconis Multiple Tuner. A fundamental wiring diagram of the Marconi multiple tuner appears in Fig. 168 and amore detailed diagram showing approximately the position of the apparatus in the tunerin Fig. 169. Like notations are used in both drawings. Since this tuner is adjustable to wave lengths between 80 and approximately 3,000meters, a specially constructed series of multi-point switches S-1, S-2 and S-3 (Fig. 169)control the inductance and capacity of the primary, intermediate and secondary circuits fora progressive increase or decrease in wave length. The particular wave length adjustmentcorresponding to any position of the switch is clearly marked on the operating handle. 150 PRACTICAL WIRELESS TELEGRAPHY. When the small D. P. D. T. switch is placed in the standby position, the magneticdetector is connected directly in series with the aerial and the necessar
Size: 2048px × 1220px
Photo credit: © Reading Room 2020 / Alamy / Afripics
License: Licensed
Model Released: No
Keywords: ., bookcentury1900, bookdecade1910, booksubjecttelegra, bookyear1917
