. An elementary manual of radiotelegraphy and radiotelephony for students and operators . apacity, mure or less throws thecondenser circuit out of tune with the antenna circuit, and there-fore varies the intensity of the emitted waves. By anv of thesemethods the train of undamped waves emitted by the antennamay be moulded into the form of speech, and these waves are thenretranslated back into sound by the arrangements employed in thereceiving circuit. 340 I^A DIO TELEGRA PHY The picture in Fig. 9 shows the complete arrangement for em-j)loying a Poulseu arc iu a radiotelephouic transmitter appa
. An elementary manual of radiotelegraphy and radiotelephony for students and operators . apacity, mure or less throws thecondenser circuit out of tune with the antenna circuit, and there-fore varies the intensity of the emitted waves. By anv of thesemethods the train of undamped waves emitted by the antennamay be moulded into the form of speech, and these waves are thenretranslated back into sound by the arrangements employed in thereceiving circuit. 340 I^A DIO TELEGRA PHY The picture in Fig. 9 shows the complete arrangement for em-j)loying a Poulseu arc iu a radiotelephouic transmitter 7 shows the multiple microphone arrangement, the mouthpieceagainst which speech is made branching out into a number ofparallel pipes, at the end of each of which is a carbon microphonemade as described, such a transmitter being suitable for radio-telephony over 250 miles. By these methods Poulsen has succeeded in transmittingarticulate speech from Berlin to Copenhagen, a distance of 46t)kilometres, or 290 miles. AVhen a high frequency alternator is used as the source of the. [Reproduced from The Electrician hy permission of the Froprie ors. Tig. 9.—General View of the Poulseu Transmitting Apparatus forRadiotelephony. undamped oscillations in the sending antenna, the oscillationscreated by the alternator are transferred to the antenna throughan oscillation transformer. The microphone may then be placedin the antenna circuit, and as near the earth as possible, or it maybe placed in a tertiary circuit wound on the oscillation transformeritself. 5. Other Arrangements employed as Transmitters in Eadio-telephony.—To avoid placing the arc in a strong magnetic field andenclosing it in an atmosphere of hydrogen or hydrocarbon, experi-ments have been made with a number of electric arcs in has already been explained, in Chapter III., that the character-istic curve of a continuous current arc is steeper for small currents ^.-/ //(/ t. LEPHOXY 341 than for l;ir;^i&g
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Keywords: ., bookcentury1900, bookdecade1910, booksubjecttelegra, bookyear1916
