Germany's Radio Capital

Radio Record, Volume III, Issue 24, 27 December 1929, Page 4

Germany's Radio Capital

A Comprehensive Plant (GERMANY to-day is said to possess the most extensive wireless station in the world. This is situated at Nauen, some 20 miles from Berlin, and it was here that the first wireless company in Germany erected its original plant. In the early days of radio communication it was mistakably believed that the longer the wayelength or lower the frequency used, tlie greater would be the distance over which the transmissions could be heard, and the Nauen station was equipped accordingly. In 1919 a world congress decided that the best way to keep amateurs from disturbing official communications

was to limit them to wave-lengths not exceeding 200 metres. With such waves, it was believed, no harm could be done. But it soon beccame apparent that the professionals had made a sad miscalculation, for the despised amateurs achieved such results that the long-wave senders began to look more like amateurs themselves. Such a development naturally had to be coped with, and the important wireless companies of the world turned their attentions to short-wave transmission. As a_ result of this, the Nauen station, which now sends the "trans-radio" messages, has been rebuilt and enlarged. As well as the two long-wave transmitters, operating on 138,000 and 18,000 metre wavelengths, seven new short-wave transmitters, operating on the 15-30 metre band, were recently installed. The installation of seven more short-wuye transmitters will be completed before the end ‘of the current year,

The mighty maze of aerials at Nauen, with its 12 high masts, two of them 8538 feet high éach, seven others each 690 and the other three each 492 feet high, is by now almost anticipated, so rapid, has been the advance of technology. The great masts are now used only for the two long-wave senders, which chiefly take care of communication with America and the Far East. Between them stand the new masts, only about 65 feet high, from which are strung the aerials for short-wave sending. These look but little different from the _ telegraph ares along the neighbouring railroad e. Two somewhat larger nets of aerials, hung from masts 245 feet high, are being built for the service to North and South America. These aerials are so directed toward the destination to be reached as to prevent the waves from going backward around the earth. With a wave-length of 15 metres by day and 25 to 30 by night, they take

care of the entire short-wave evant above all to South America, Siam, Manila and Cairo. This short-wave traffic will soon be extended to Mexico, ' and perhaps also to the British dominions, in case an agreement can be reached with the British Government, UNDERNEATH the great web of aerials stands the station’s power plant-for all the world like a great spider in the middle of its net. Here the great generators hum -their monotonous song, bringing the electrical current up to the vast tension of 120,000 volts for the two long-wave senders. They run day.and night with out ceasing. One of them has been running ever since 1916, with a pause’ of but four hours per week., Every transmitter at the Nauen station is operated'from the central office at Berlin. Thus the station requires only sufficient employees to (Concluded on page 29.)

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guard the plant and see that the purely mechanical equipment functions properly. The entire staff. consists of only sixty persons. The enlargement of the station made possible a very considerable increase jin it& efficiency. This is due chiefly to the improvement of the short-wave transmitter, which makes possible the transmission of from 150 to 200, and under special cirecumstancés, as many as 300 words per minute, The latest stage in the advance in wireless communication was the ‘introduction at the end of last year f wireless" telephony with Buenos aires, a distance of some 73800 miles. This service is to be extended to cover the entire Argentine and also to other South American stations. And the next step will be the transmission of pictures, which now, after long experimentation, is about ready for practica)

Indoor Antennae. FROM the point of view of reception, ~ the indoor aerial is better than a loop antenna. The pick-up of the latter is small, and, in consequence, an extra radio-frequency valve is usually necessary to compensate for this. An indoor aerial, on the other hand, while not possessing the sensitivity of the outdoor arrangement, is nevertheless capable of giving good results, especially on the higher frequencies. It is as well to carry out experiments with indoor aerials of various types, since the disposition of the wires frequently has a marked effect upon signal strength. Home Construction. THE wiring up of a receiver will be found a great deal easier if the components are prepared before they are mounted.. This is done by filing clean and tinning all soldering lugs and other points to which connections: are to be made. After tinning @ amall

Ta = oD SSS SED onal — "blob" of solder should be placed on each lug. This will be sufficient for making the connection and it will not be necessary to add any more while wiring. Working Moulded Eboniie. GHARP drills are essential for working. moulded ebonite, and the smallest possible pressure should be applied. When it is necessary to make a hole through a thin moulded flange or through one of the ribs of a ribbed coil former, it will be found safest to make a preliminary hole without a drill. Take a fairly stout needle (it need not be sharp), heat it red hot and push it through the ebonite. holding it in a pair of pliers. It will be found necessary to withdraw the needle and re-heat it several titnes before the hole is complete. Finally, if a moulded ‘ebonite component is to be screwed to the baseboard of a receiver, wuvoid screwing the component down too tight-

=a ene ly as moulded ebonite sometimes be-_ haves like porcelain, splitting if the least bit too much pressure is put on a weak point. An Earthing Precaution. ANY.amateurs use two earth con tacts of different kinds under the' impression that such an arrangement gives better results. If a copper and a zine plate are buried in different positions and connected, an electric @ell with its two plates of dissimilar metals is formed. The electrolyte ig composed of the moisture and acid in the soil and the outside circuit consists of the earth leads. A microammeter (or even a milliammeter in some eases) placed in one of the earth leads will indicate a flow of current, and this current can be produced only by disintegration of one of the plates. Further, such an arrangement may quite possibly be the cause of background noises in a sensitive receiving set.