Zeesen Short Wave Transmitter
-eeeeme WEEKLY reports of reception of Zeesen station appear in these columns, so the following technical description (from "World Radio") will e of interest, Designed for the purpose of worldwide broadcasting, the new short-wave transmitter at Zeesen has recently completed a series of ‘experimental transmissions. extending over Several weeks, and is now operating on a regular schedule, relaying the Konigswusterhausen. progtammes from seven o’clock G.M.T.) each evening. The apparatus of. the new station is actually accommodated inthe, same building as the Kinigswustersen long-wave transmitter, "and the ial "employed, a single wire approxini@tely 55 metres in length, is attached to one of the existing masts which Support the larger aerial. Like the apparatus of the long-wave station, the new transmitter was constructed by the Telefuken Company, and is very similar in general design to the powerful short-wave. sations recently ‘built at Nauen and -Buenos Aires, by means of which telegraph, telephone, and picture ‘transmission services are maintained between Germany and the Argentine. The power rating of the new sta-tion-i.e., the power in the aerial when the transmitter’ is operating, but no modulation applied to the carrier waveis. 8 kilowatts, and the’ normal wavelength is. 31.38 metres. / Arrangement of Apparatus.
al ‘} 4445 transmitter comprises seven stages, _ the crystal control of oscillation being applied to the first stage. "The desired short-wave is obtained by selecting a harmonic of the erystal fre-quency~-which, for practical reasons affecting the reliability and. life of the crystal, is lower than that corresponding to a wavelength of 31.388 metres--and amplifying and filtering the selected har- . monic frequency in succeeding stages uniT a til the desired wavelength as well as the ‘required power’ are eventually reached. Naturally, the valves used are of increasing power-handling capacity in progressive stages, from the ordinary type of power amplifying valve in the first stage to two 1,500-watt-. power valves in parallel in the fifth and sixth stages, at which latter point modulation is applied via three power valves operated in parallel. The seventh, and final, stage consists of two 20-kilowatt water-cooled valves connected for "push-pull" amplification. : Power Supply. various types of valves employed necessitate different. supply yoltages, Power is obtained, initially, frgm the main station transformer, which is}fed from outside power mains. The tyio water-cooled valves in the last stage are fed with anode current at 10,000 volts, generated by a high-tension, directcurrent dynamo of 50-kilowatt capacity. Anode current for the valves in the fifth and sixth stages is supplied by a 4000-volt, 5 kilowatt machine, while the remaining stages, with the exception of the crystal-controlled oscillator, which has its own 220-volt, direct-current generator, are supplied from yet another direct-current dynamo at 2000 volts, the power rating of this machine being 2 kilowatts, ¥or filament heating there are provided two separate dynamos: one giving up to 5 kilowatts at 40 volts, and the other giving 2 kilowatts at 20 volts. In addition a special machine is provided for the filament heating of the modulator valve. Grid bias for the two large output valves (seventh stage) is obtained from a special 750-volt, 2-kilowatt converter. , Control arrangements throughout the station are of the most. modern type;
all the generators mentioned are started by means of push-buttons on a central switchboard which is situated in the basement of the station building.
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https://paperspast.natlib.govt.nz/periodicals/RADREC19300110.2.68
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Radio Record, Volume III, Issue 26, 10 January 1930, Page 31
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548Zeesen Short Wave Transmitter Radio Record, Volume III, Issue 26, 10 January 1930, Page 31
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