NOTES AND COMMENTS

Radio Record, Volume I, Issue 31, 17 February 1928, Page 8

NOTES AND COMMENTS

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A hydometer will enable you to test an accumulator, or wet battery, quite well, if not better, than a voltmeter, If a wet "A battery be allowed to stand in a discharged coniition for very long it will be seriously attacked by sulphate and may be injured rather adly. An important judgment was given recently in the High Court, when £150 damages were awarded to the author of the musical play "The Little Michus," which had been broadcast by the B.B.C, This was deemed to have infringed the author’s copyright. On Wednesday, December 28, last, Harry Lauder made his final appearance before the microphone in London before sailitig for Australia and New Zealand. The public kept him going for three-quarters of an hour. Sydney stations may possibly engage Sir Harry Lauder to broadcast some of Lis wonderful Scotch wit, in which case we may look forward to something worth while. One of the commonest causes of poor reception in a crystal set is a dirty contact at the lead in or the earthing switch. Many radio fans have desired to know the polarity of the ordinary torch battery contacts in order that they may be used as a makeshift. The long contact is the negative and the short one is the positive. Professor Bergonie, who invented the X-ray and died fron X-ray burns in February, 1926, had, before his death, jnvented a radio chair. hough his invention was patented in 1911, it has only been recently that hospitals in Svdney, Melbourne Adelaide, Perth, and hospitals in England, Germany, and America have been fitted with the Bergonie chair, An ordinary flash-lamp bulb connected in the "B" battery negative lead makes a very good fuse and may save your valves in the case of a short circuit. If you are running long leads through the house se that the loudspeaker can be used in different rooms, it is a real economy to use a choke-coupled or a transformer coupled output to prevent H.T. leakage. The proper way to disconnect batters leads is at the battery end, not at the set end. if the wires are separ--ated from the set end, and left on at the batterv end, there is a great danger of shorting the battery. Where trams or other electric machinery cause interterence, it is often found that a counterpoise gives better results than the usual waterpipe or buried plate earth. The Sydney ‘‘Wireless Weekly’? publishes the following:-‘Mrs. Ruth Hf. King, co Mrs, F. Murray, P.O. Box 199, Greymouth, N.Z, is anxious to learn the whereabouts of her brother, Bertram P. Adams. He was a wireless officer, and was last seen in Australia. Will anyone knowing his address please eommunicate with Mrs. King?" Details have been published of a proposal for a new wireless tower in Berlin, which will be completed by 1939. The tower will be 2160 feet high, more than twice the height of the Tiffel Yower, with a restaurant on a slowly revolying floor so that guests can watch the changing view in comfort. A suspended railway will cariy passengers from the height of the restaurant across the woods and water to Potsdam. She light on the top will be visible 100 miles awav .

Be caretul when ustig ammonia for cleaning the sides and tops of accuimuJators. If anv ammonia should come into contact with the electrolyte, the Jatter will become neutralised. Every time a’ pair of telephones is dropped on the floor the magnetism is weakened, and the life of the telephone made shorter. When a set which has hitherto heen well behaved starts to howl and distort, the most likely cause of the trouble is the run-down condition of the ‘‘B" battery. . . Audie-frequency amplification will give greater volume on local stations, but radio-frequency amplification has the characteristic of being able to amplify a weak signal, therely increasing the range of the recciver. A constant humming noise is generally due to the fact that either the aerial or ‘the earth lead, or the set itself, is too close to the electric light mains. (Remember, that these are sometimes concealed in the wall.) Sometimes it does not matter in the least if the "A’’ battery has been accidentally connected the wrong way. round-ie., its negative to L.T. plus, on the set, and its positive to W.T. negative. Occasionally, as a matter of fact, this’ improves reception. All ship stations with amateur calls. place an X before their usual intermediate, e.g., Australia 3AA at sea, calling U.S., IAW, would send "1A W NUXNOA 3AA," The reply would be ‘3AA XOANU IAW." The OA, of course, is the prefix for Australia, and NU is the prefix for U.S.A. "To not set your watches several times a day by the wireless," writes a preminent watchmaker, Doing this, he states, will only serve to make the watch more inaccurate than before, lrony!

An American radio manutacturing company announces the development of a new five-prong socket for use with the new five-prong valves. This socket possesses some exclusive features. It has a guide yroove, by means of which the insertion ot the valve into the socket is greatly facilitated, particu. larly so when the tube socket is located within a shield or can devoid of sufficient light. ‘ihe socket is adaptable for baseboard or suhbpane} mounting, regard» less ot the subpanel or baseboard material. When used for subpane] mount ing, it is unnecessary to resort to the use of fly-cutter. The socket contacts slide thhrough smal) holes drilled into the subpanel. Many and varied are the ideas put fot~ ward for removing dust from the plates of the condenser and other internal parts of the set where dirt will cause losses and noises ‘The use of an ordinary duster may injure the. delicate coils or condenser plates, and do more harm than good. An excellent method 1s to use the vacuum cleaner, utilising one of the attachments provided for working in small ploces. A ventleman who 1s a radio dealer in San Pedro, the port of Los Angeles, California, writes to thank one of the Australian broadcast stations for their programme, which he says is greatly enjoyed by ail, since American musical programmes are composed mostly of advertising matter. He offers 500 dollars for every programme of the same quality put over the air, and further invites the Australian announcer to drop into his heme when next he is at San Pedro. The ultimate elimination of 300 American broadcasting stations is promised by Mr. Pickard, chairman of the United States Federal] Radio Commission, who states that the radio channels can be cleared only by this means Plans for the great shut down will be begun shortly. It costs from 5000 to 10,000 dollars a month to operate a broadcasting station in the United States.

Many radio fans find that after their storage battery hus been in use for a short period, a greenish, or, sometimes, whitish, substance gathers about the positive terminal, while a small quantity of a grey substance forms at the negative termiual. ‘(his coating prevents the obtaining of a good contact, and must be thoroughly scraped off. or wiped off with a rag damped with liquid ammonia. The best way of overcoming this trouble is to coat the terminals of the battery with vaseline, It is well to put vaseline on the battery clips also, as it protects the metal from the action of the electrolyte and thus prevents the formation of the unwanted substances which make poor electrical contacts, Where a reamer is required but n available, a pair of comes fn handy. If the hole in a piece of wood or bakelite is just a little too sniall one of the blades of the scissors should be inserted and turned in a circular motion so that the sharp edge will enlarge the hole eveuly, An American newspaper lauds the arrangements made in Russia to install community sets in order that the public may listen-in. At some length the article describes how every hamlet, village, and city is being fitted with bhighpowered receivers, and a well-known member of the Chicago Radio ComuisSion iusists that a great amount of credit is due to the instigator of this idea. Where markings are required on the panel of a home-built radio set, these are easily made by scratching the panel with a scriber or other sharp instrument, and filling the scratch with white chalk or crayon. ‘The crayon is simply rubbed over the surface, enough adhering to the scratch to make a clear marking. Many beginners at constructional work find it rather diflicnlt to punchmark a panel accurately as a preliminary to drilling. Even if the marking out has been done with considerable care and accuracy many of the centres do not lie, as they should, at the junetion cf the cross lines made with the scriber. One of the commonest causes of inexact centre punching is to be found in the use of a tool that is unsuitnble for the purpose. For wireless work, where most of the holes are made with small drills, the best type of punch is one that tapers gently to a fine point. The more or less roundpointed punch with a steep taper is Bt at all what is wanted. It is noteworthy that the Scandinavian listeners are much interested in the progress of Empire broadcasting. When a special programme from 2FC was rebroadcast thronghout Great Britain recently, thousands of listeners in Scandinavia tuned in to Daventry, Iineland. Though speech was not too clear, the musical items came throngh verv well. Discussine conditions in Western Australia, Mr Baty, of Perth, a recent visitor to Svdnev, stated that radio is in a very bad nosition, and, according to his advices, licenses, which are now approximately 4,099. are dropniny at the rate of from fiftv to one hnndred per month. The trouble is that listen-ers-in in the Western State are gener ally wnahle to receive broadecastiny from the East Australia. As GWE is on 1250 metres, and it is dificult te desien a receiver which is efficient on both long and short waves, husiness is suffering as the result. At preset! matters are at a deadlock, as according to Mr. Baty, BWF will not consider a reduction in wave-length to bring the station into line with the other Australian stations. When chargine storage hatteries. alwavs remove the vent cans. These caps help to keep away the air from the electrolyte in the hatterv, thus preventing evaporation during use of the hbatterv. During the recharging process, especially where a hich chareing rate is used, the solution evanorates more rapidlv. and the caps should be removed so that this vapour can be diffused readily. In some instances the vanonr, when mixed with air, would he inflammable, and if the cap is suddenlv removed after charging, and an open flame hannened to be nearhv, an exnlosion micht take place. For this reason a match shonld hever he nsed to examine the level of the electrolvte, esnecially durine or immediately after charee, A’ small flashlioht should he used for this purnose. Tywards of 2500 firms in the United States are now manufacturing radio sets and parts, A piece of adhesive tape wound about a valve so as to cover the junction between glass and hase,- will nelp to prevent vibration of the valve, and will also prevent the glass from becoming loose from the base. Only a single turn is necessary. Radio, except for educational and experimental purposes, is banned in China, and cannot be legally imported. For these purposes a permit may be obtained from the Central Government. In addition to the fact that China owns and controls the means of telegraphic communication, the Ministry of War regards radio as munitions of war, and, therefore, its importation is prohibited. We must not forget, however, that war is going on in China. The Danish Minister of Public Works recently opened the new _ broadcast station established by the Government near Kallundborg, in torth-west Zeeland, in which function he was assisted hy the president of the Radio Council, The station has an input power of seven thousand watts. *

Tf, sulphuric acid from an accumulat- « is spilt on a floor or a carpet, it. will rapidly "eat it away," unless the sulphuric acid is neutralised. This can be done by amunonia, or ordinary wash. ing soda, or even bicarbonate of soda, if applicd frecly, and at the fullest possible strength. } Did you know that when a set slowly builds up an oscillation (or howl), the tronble is generally due to the fact that the loudspeaker is too close to the set, or is pointing directly towards i In homé-made wet ‘B’ hatteries (high tension accumulators), it is necessarvy to insulate each cell from its neighbour, otherwise, instead of voltage, you will get trouble. When a wire is joined to one side of each of two condensers, and another wite to the other sides of both, they are said to be in parallel, and their capacity as a total will be the sum of the separate capacities. For instance, a .0002 mfd, and a .0003 mfd. condenser connected in parallel would give a total capacity of .0005 mfd. | It is generally the obvious troubles, such as the use of a piece of oa flex, or a valve, which is making faulty contact with its valve holder, that get overlooked longest, Always attend to the obvious first, after which the various conditions of the parts can be attended to,

A New South Wales listener writes to the Melbourne ‘‘Listener-In’’; ‘I have noticed that 21°C nad 38AR are practically free from static, and when I tune down to 2BL, static is much more intense, and practically blots all the lower wave-length stations out. 2GB and 5DN seem to be practically on the one wave-length, but on a night fairly. free from static 2GB comes in very plainly, with just a slight heterodyne whistle. 2IFC is received here very plainly, but fades occasionally. 40G_ used to he very good, but now comes in very distorted, like 7ZL. My set is a 5-yalve Browning Drake." _ The old broadcasting station at Soro, has been closed, and its place has been taken by a new and improved one at Kallundbore. The new station relays the Copenhagen service on the same wave-length that Soro used, but uses a power of seven kilowatts, as compared with only one kilo-. watt at Kallundborg. | A good rough-and-ready test for oscillation is to wet the finger and tonch the aerial terminal with it. If a loud "click" is heard every time the finger both touches and leaves the acrial terminal, you can be certain the set is oscillating and causing interference with other listeners, When working on the short waves the aerial coil should he conpled loosely, or the set will tcfuse to oscillate,

The call sign of the Siberian shortwave broadcast station is RIM. ‘This station was installed by Carl Madsen (NU.9.EKO), of the Westingfionsé Etec. | tric and Manufacturing Co. of America, The power used is 20-000 watts, aud the working wavelength 60 metres, but there is also a very powerful harmonic or a duel wavelength on 30 metres. ‘Ihe installation is crystal controlled and the modulation is remarkably good, The location of this station is Khabaroysk, Siberia, U.S.S.R. (United States of Soviet Russia), This station works nightly between 10.30 p.m. and midnight, and transmits some very good ° f music, both orchestral and vocal, The capacity of the average 100-foot broadcast listener’s aerial is in the neighbourhood of .0002 or 0008 mfd. Liege (Belgium) is already arranging for its second International Broadcasting Exhibition, which will be held in the Palace of Arts from March 10 to March 25 this year, and is expected to comprise representatives of all im‘portant countries of the world. Always place your accumulators on an old magazine or a piece of wood, as there is a lot of loose acid about at a charging station, and, however carefully the cells are roped, there is a possibility that a very fine film of acid may be left. Sulphuric acid is extremely corrosive, and it does uot take match of it to run a carpet or damage the inside of a radio-set cabinet. By abolishing the usual grid teas and condenser in favour of an audiyv transformer, whose secondary is cuonnected in series with the grid leak and the .0005 condenser, which is placed across the A.J, coil, clarity of pralu--tion will be improved greatly. ‘This is a new idea which now appears in a number of American citcuits. The Sydney Trades Hall broadedst station, 2K Y, will shortly be buildmy uew studios in some central place in the city, announces Mr. Beayer, manager of that station, Present arrange- — ments are unsuitable, and it is hoped to have conipleted the arrangemests shortly, Their present studios are situated in the Trades Hall, in (s11burn Street, Sydney. Signals which have passed arouid the world in the reverse direction frou transmitter to receiver, or have passed more than once completely around the world, are known as radio echoes, hecause they make themselves manifest in the receiver as echoes make thesselves manifest in acoustic phenomena. Iicho signals not only have intense scientific interest, ‘but with the advent of more and more stations in the very high frequency bands, have become of very great practical importance, because of their disastrous effects npn reception at certain times. It is amiacing that those echo signals which have been photographically recorded, aftez having passed approximately two anid one-half times around the world, are of sufficient intensity to cause very serious interference. : The presence of the grid leak makes no difference to the voltage applied 1 the grid provided that the valve is properly biased, for it is not until errrent flows that a resistance in series will cause an appareit voltage drop, and as no current should be allowed to flow between the filament and grid of the last valve, there is no loss wi yoitage in the circuit. © The broadcast of a Punch and July show in London recently met with great success. She average listener probably knows nothing of the history of this famous character who actually lived. He was a hiuneh-backed Italian actor, whose performances became so famous that the puppet-show for which Italy is so famous, inutated and perpetuated him in the show which st! makes the whole world taugh. Next Christmas should prove inwre-t-ing if certain proposals by the B.D.c. eventuate. It is suggested that an Empire Christmas party he broadca+t from London, and ihe following wetlknown personalities have approved of the idea-so we hope to hear more later:-Mr. Rainsay MacIonali, P.C., MP.; Lord Danesfort, president of the British Empire Union; Sir Godfrev Laugden, K.C.M.G., K B.l., vice pre.?dent Royal Colonial Institute, and of the African Societv; H H, The Mat. rajah of Rajpipla; Miss Pauline I’rederick; the Right Hen. J. Wo Tomns, M.P.; Colonel Hairy Day, M.P. Now that PCJJ has been dismantled and re-erected at Milversum, a bricf review of its work may not he amiss, for it has certainly made radio history. It began by working on 30.2 metres when Australia spoke very well of its signals. Then on May 2), 1927, it had the andacity to relay Daventry, its signals beipr well receive? in Australia, New Zealand, India, end South Africa. Dr. A. Hoyt Taylor, superintendent of radio at the Bellevue Naval Research Laboratories, U.S.A., defines the quartz crystal as a plank in the Teague of Nations-capable of avoiding internation disputes by reason of its previseness in controlling the assigned wavelengths of transmitting stations the world over, ‘The Bureau cf Standards rates this mineral more valuable than diamonds and gold-it being so relatively rare and precious as to precipitate a struggle between certain cont211:1ing force the triumph of either faction meaning a monopoly of this master key to successful, interference-free tadio broadcasting. ,