Radio Review

Evening Star, Issue 19782, 4 February 1928, Page 20

Radio Review

. [By “HENRY.”]—

Flashes from Everywhere.

RADIO IN SCHOOLS. , Following . upon the paragraph which appeared in last wek’s notes on Radio in schools, an extract from the ‘ Journal of Education ’ should be of interest. Hero it is; “'The educational possibilities of broadcasting were not overlooked in the debate in Parliament on the proposed Royal Charter under which a small corporation of paid members will in future control this important work. Lieut.-Colonel 0. Stanley pointed out that industrial students showed great interest in political science and political economy, and it would be unfortunate if these subjects were barred because of their controversial character. It was easy, ho said, for a first-class tutor to deal with a controversial topic in an irreproachable way. Educational interests are represented on the new Board in the person of Dr. M. J. Rendall, and the record of the British Broadcasting Company which the new corporation is to re, place is a good augury for the sympathetic treatment of these important interests. We hope that teachers will be prepared with constructive suggestions to increase still further the'usefulness of broadcasting in our schools.” EXPERIMENTS WITH AERIAL There is still a great deal to be d6ne and much pleasure to be obtained in experiments with outdoor 'and indoor aerials. Far too much attention is devoted to the set itself and far too litle to the humble wire which serves as a collector. Many owners of really sensitive four of five-valve sets use them with far too big aerials. Large, high aerials are great collectors of static interference and those electrical discharges which cause the _ rumblings, crashes and cracks on certain evonuigs, particularly •diming summer-time. The aim of all experiments should be to get the highest ratio of signal to background noise, and a station of medium strength against a practically inaudible “background” is far easier to identify than one which gives loud signals to the accompaniment of almost as loud crashes, bangs and crackles. With crystal sets, of course, the largest possible aerial should be used. _ Try entirely disconnecting the aerial and joining the earth lead to the aerial terminal? Results will be surprising. Excellent work can also be done by burying a carefully insulated wire (the wire, sold as “ acnal load-in ’’ and \ery thickly covered with rubber is best). If care is taken to prevent the wire coming in contact with the _ earth at any point—the end of the wire buried in the ground should be sealed with insulating tape~and if an ordinary buried earth connection is used, a great deal of interesting information can be gathered. Buried aerials are by no means new, but for some reason or other they have received little attention from the amateur.

EMPIRE BROADCASTING. Empire broadcasting from 6SW at Chelmsford has come to a temporary stop. Tho 8.8. C. is disappointed with the results of the first experiments on the 24-metre wave (states ‘The Electrician’) and now, it is understood, slight alterations have been made in the apparatus to permit the use of other short waves. Before the employment of new frequencies, however, permission must bo obtained from the Post Office, and presumably the 8.8. C. is awaiting this permission before embarking on a fresh series of tests. The 8.8. C. is carrying out experiments by arrangement with Marconi’s Wireless Telegraph Cb.,. and the programmes a're, in the main, to,be relayed from London. ; The laboratory and test room of the Government Radio Research Station at Ditton Park, near Slough, were recently destroyed by fire, resulting in the loss of wireless apparatus valued at several thousand pounds. The lattice mast, some 200 feet high, was soon on fire, and eventually crashed to the ground. . • In view of statements in the Press that “ the position in relation to radio and cable services is under consideration between the Government and cable companies,” and of other statements on the subject, Mr 1. 6. Ivellaway, managing director of Marconi s Wireless Telegraph Co., Ltd., stated the position of his company in an interview with the Press. Mr Kellaway said the Marconi company had not been invited to take part i„ any discussions which were proceeding between the cable companies and the Government. As the interests of tho Marconi company must be involved, they assumed that no .decision affecting their interests would be taken without the company being given the same opportunity of stating its view as was being given to the cable companies. Pointing out that the Marconi company had not asked for State assistance for its telegraph’ services^ in the form of a subsidy or in any other form, Mr Kellaway said they could not agree that any such assistance was necessary for either the cable companies or the companies. If the cable companies or the Marconi company could afford to carry telegraph traffic at low rates they should be allowed to do so.

With the exception of tho Empire beam services, worked by the General Post Office in England, and by the Marconi company’s associated companies in South Africa and India, and by the Amalgamated Wireless (Australasia), Ltd., in Australia, the wireless rates were the same as the cable rates, and wireless was securing a large and growing share of the traffic. The statement that “wireless between England and the United States of America, where rates are tho same, has been unable to obtain a reasonable proportion of the traffic” was altogether inaccurate. Whatever decision was arrived at as to the future relations of the two systems of telegraphic communication, it was inconceivable that the British Government would Assert# to any arrangement ■ which • irt 'any way hampered the free development of wireless communications. When the system of facsimile transmission, on which the company’s experts were now engaged, was perfected, it would be possible to, reduce substantially the costs of operation of the wireless telegraph services. In the company s view > any such reduction in costs should be reflected in a reduction m telegraph charges. To standardise telegraph ratesV to restrict the wireless services to the less important classes of traffic would sterilise wireless development and keep up rates. The cable companies, in their various communications to the Press, had dwelt on the importance, from the strategical aspect, of maintaining the cable systems of the Empire. The last war proved that cables were the most' vulnerable of all forms of communication. Every German cable was cut by tho British Government within twenty-four hours of the outbreak of war. But, thanks to her wireless station at Nauen, Germany was able to maintain telegraph communication with tho whole world throughout the war, and. the Allies, in spite of their command of the seas, were never able to sever those communications. ; , On the other hand, although' the German fleet was “bottled up, the Germans cut the British 1 acibc cable for a poriod of six months, ihe Marconi company desired to make it clear that it was prepared to discuss with the cable companies any means of cooperation, provided that nothing was done to restrict the development of wireless.

LONG DISTANCE ON A CRYSTAL SET. The coming of SGB had one very unexpected effect —it revived interest in the possibilities of long-distance reception with a crystal set (says an English writer.) Many a listener, who had tuned his set to try and hear the alternative programmes provided by Daventry Experimental, had astonished himself by picking up a foreign programme, instead! Lagenburg, whose wave-length happens to bo near that of SGB, was picked up at such strengh by one Essex listener that it was assumed to be Daventry Experimental until the announcer said a few kind words in unmistakable German! 1 , ADJUSTABLE ’PHONES. Many people use the type of telephones which are adjusted by means of a milled knob on the back of the earpiece. The effect of adjusting this knob is to bring the diaphragm nearer to the pole-pieces. Now, since distance of the diaphragm from the poles of the magnet varies according to the amount of steady current flowing through the telephones, it stands to reason that what is a correct adjustment for a valve set is not correct for a crystal set (says the ‘ Wireless Constructor.”) In order to work with the telephones as sensitive as possible, a habit should be made of adjusting* them immediately on connecting up a different set. It will also be found an advantage to readjust the ’phones when listening to very weak signals, because when signals are weak it is possible to have the diaphragms closer to the magnets without “dithering” than with loud signals.

NO LONGER AN INFANT. Radio is no longer the “child prodigy,” or the “infant industry,” as it has been turned time and time again by well-meaning persons. “ Proof of this,” said a radio trade leader, in America recently, “ is_ readily obtained by a brief inspection of what has transpired in the past few months. First in the changes which have taken place was the bringing of order out of chaos when the Congress _of the United States singled out pur industry, at our request, and gave it the Radio Act of 1927. Its executors, the Federal Radio Commission, has done what is, to my mind, a splendid job in its first clean-up of the broadcasting situation, and the public has been quick to sense the success of its work. • “ Following closely on this first change came the broadcasters of the country in grasping their opportunity to give to the public programmes far superior ‘to any they had heretofore delivered. Look, if you will, for a moment at the nation-wide broadcasts which have been made in past months. In quick succession came the emergency call for the Mississippi flood work; Memorial Day celebration; Lindbergh’s reception, the all-night vigil kept by both seaboard and inland stations when Commander Byrd was lost; again, his reception; the Demp-sey-Sharkey fight; and just recently an international broadcast over Canadian and American stations of interest to many. . “ Everyone believes m radio as never before. No longer is it a novelty, It has now taken its place as a fully developed industry. , “The first responsibility is to mum dependable equipment and to merchandise it as such. That equipment, regardless of whether it is a completed set or only one of the component parts of radio, must: faithfully reproduce for the listener that which is broadcast, with the simplest operation possible and the maximum of dependability. “Let ns dim to get those fine notes of the artist’s voice, full clarity of. the spoken word,'and all that the symphony orchestra of band represents delivered to the listener with simplicity, ease and reliability.”

RADIO FOG. Radio fog, one form of interference, strangely enough, is said to be more prevalent at night, than in the daytime. A report from Chicago, states that following observations with a ninetube super-heterodyne and a fojjrtuber, ‘ power, clarity, and tonal quality of many broadcast stations were marvellous. At night, the , same stations were weaker and the quality changed for the .worst. There seemed to exist a kind of interference which could not be tuned out; musical selections lost their true character, and speech became harsh and grating. Citing a simile, it is said we do not see the sun in its true character in a fog and at night, when the too numerous stations are operating, a “radio fog” of side bands and harmonics seems to weaken the signals of certain stations and distort them. 1928-29 LICENSES. In a little less than two months radio licenses in New Zealand will require renewing. It is understood that in view of the congestion created after March 31, last year, the postal au r thorities will renew the licenses from now on. A number of listeners have already availed themselves, of the opportunity of avoiding the eleventh hour rush. The amount charged annually for. a receiving license i? thirty shillings. RADIO GATE-KEEPER.

A radio thief-catcher is used in Berlin, according .to reports ' ' It is an electrically wired gateway, which is designed to be placed at the exit of factories and mines. A gate-keeper with a pair of head-phones listens as the workmen pass out. The electrical apparatus is so adjusted that Whenever an extra- amount of metal is carried through the gate, a sharp-sing-ing noise is heard in the head-phones. Small metal coins, or a pocket knife, are not noticed, but larger amounts of metal concealed on any workman are immediately detected. This appliance is to be used to stop the theft of precious ; metals and, tools by employees.'' ' : ■’ ‘ ’’ ' .

“Henry" will be pleased to answer any questions through this column relating to the fascinating hobby. Each oorrespondent must sign his name and address (not necessarily for publication). Newsy items will be welcomed.

STATIC. ’ bugbear of wireless. . TESTS IN VICTORIA. Ever since the memorable day in December, 1901, when Guglielmo Marconi; then a young Italian student of' physics, extending experiments begun in his father’s garden a few years before, picked up the first wireless signals transmitted across the ' Atlantic by using an aerial supported by a kite flown in a gale of wind, atmospherics, or “ statics,” as they are generally called by wireless listeners, have been one of the worst bugbears of wireless. Although a great deal of work has been done in other countries to ascertain the cause of static, and devise means for its elimination, this branch of wireless research has been very little exploited in Australia. It has, therefore, been decided by 3LO, Melbourne, acting in conjunction with the Wireless Institute of Australia, to conduct ,a State-wide series of observations on static. ' The object of these tests will be primarily to ascertain the districts in Victoria where interference from static is worst, and to endeavor to show how far the interference caused by a single burst of static may extend. Secondary objects will be to establish a connection between the occurrence of static and prevailing weather conditions, and to show if the majority of static heard in Victoria originates in any .particular area. Interesting observations made in Great Britain recently showed that a great deal of the static heard there originated in Africa, about the Sahara Desert, and it is quite likely that the source of much interference in Victoria may be found to lie in the dry areas in Central Australia.

The observations will be spread over about four weeks, and the assistance of about fifty listeners scattered widely through Victoria will be sought. Each listener who agrees to take part in the tests will be provided in advance with a copy of a passage to be read out from 3LO, Melbourne, to form the subject of observation. As the passage is read out the observers will follow it. Every time a burst of static is heard the observer will make a vertical pencil line through the /word affected. If the burst of static is. a weak one. only one pencil line will be drawn. If it is of moderate strength, this will bo indicated by two pencil lines, and if it is very loud three pencil lines will be drawn through the word. By comparing the markings on copies of the passage received from different listeners the radius of any one burst of static will be found, and the districts in which interference is worst will also be indicated. Much valuable information concerning static is hoped for from the analysis of the papers received.

. WORLD BROADCASTING. Much success has attended the short-wave transmissions that are conducted from Studio 3LO from 4.30 to 6.30 every Monday morning. The reception in England seems to be particularly good, and letters have been , received from all parts of England commenting upon the excellency of the ! transmission and items, and, as everything coincides with the studio log, it is safe to surmise that the programmes so carefully arranged in Melbourne are ’lclearly heard and thoroughly appreciated on the othef side of the globe ' REFLEX RECEIVERS. If properly wired, a reflex receiver will perform remarkably well. It must be x’emembered the valves in these receivers are doing double duty, as both radio-frequency amplifier and audio-frequency amplifier at the same time, and therefore cannot perform at maximum efficiency. But reflex does give good results when used properly. HERE AND THERE. The television and noctovision experiments and demonstrations which were recently staged in England failed to hit the public' imagination. Quite good results were obtained, but semehow this seeing by wireless in the dark before we can see by it in daylight makes the whole thing look unreal. Daventry Junior is already sharpening the wit of thousands of experimenters at home, who find perhaps for the first time that they have, as far as strength is concerned, the equivalent of two “local” stations, so that if they wish to get one satisfactorily clear of the other, their sets must be really selective.

“Aerial” of the Christchurch ‘Star ’ offers a good suggestion in connection with 2YA. He writes: “Now that New Zealand possesses one of the finest broadcasting stations, in 2YA, Wellington, there is no reason, beyond that of cost, why 2YA should not copy 2FO and carry out simultaneous broadcasts on 422 metres and on the short waves—somewhere around 30 metres.”

The King is the possessor of his own microphone. Reserved exclusively for the King’s use, it is enclosed in a rich filigree silver case, which bears inscriptions showing the exact dates cn which the King has spoken through it. In design the microphone is exactly similar to those used in broadcast stations. A “shielded receiver” is a set in which part or all of the apparatus las been enclosed in or electrically protected by a metal casing or partition. Radio programmes are carried to listeners by electrical waves travelling at the rate of 186,000 miles a second.