THE WIRELESS WORLD

Otago Daily Times, Issue 20283, 16 December 1927, Page 5

THE WIRELESS WORLD

NEWS AND NOTES. By Magna Vox. Items of local interest are invited by “ Magna Vos ” for publication in this column. It is necessary that such matter should reach this office by Tuesday of each week for insertion on the following Friday. ANSWERS TO CORRESPONDENTS. “ Inquirer,” Henley.—The length you mention ig unnecessary. Roughly, for general receiving purposes, 75 to 80ft exclusive of the lead in, should be sufficient. J. B. G., Mosgiel.—-A cat’s-whisker is a little coil of fine wire, brass, silver, phosphor bronze, gold, or steel; about 32 or 34 S.W.G. “ Short-Wave,” Oamaru. —Station W.L.W. is at Cincinnati. U.S.A., and broadcasts daily on a wave-length of 52.02 metres. KDKA is a Pittsburg (U.S.A.) station with wave-lengths of 14 and 62 metres, which, however, will shortly change to 26 and 52 metres. . “ Amateur,” Ravensbourne.—With a Tshaped aerial, the lead-in should he attached to tho very centre of the aerial, otherwise the latter will consist of two unequal parts, each with its own wave-length. In, the latter case, anything like sharp tuning will be impossible, since the two sets of oscillations will fight one another. “Battery,” North-East Valley.—lf, as you say you used old wire to connect your A battery to the set, this, is probably the cause of your short circuit. Buy good, heavily insulated wire, and if a break in tho insulation should occur, replace the whole wire. Do not attempt to splice in another short piece, ns this will probab.ly lead you into more bother. SCOTT’S RADIO HANDBOOK. The fourth edition of Scott’s Radio Handbook, which is lust to hand, is a particularly useful little" volume which should prove a boon to every wireless enthusiast, especially the amateur. Somewhat larger than the previosu editions, the book contains 96 pages of interesting and useful matter, written in a singularly lucid style, and not overladen with technical terms, the author knows his subject thoroughly, and amon ff others, his treatises on crvstnl sets and amplifiers, aerials, short-wave adapters, the Hammerlund-Roberts 4-va.ve set, and the Loewe triple valve set, are particularly instructive and informative. A number of clearly-drawn and well-explained constructional diagrams are given, and in addition, a comprehensive budget of miscellaneous information relative to • the principal broadcasting stations, short-wave stations and comparative times throughout the world are also includcdintheyolume. As its fore-runners have done, this nddi tion should prove a friend m need to every amateur listener. A MAKESHIFT “EARTH.” A good make-shift “ earth ” can be fixed up by country dwellers who cannot obtain the use of a waterpipe, and is oiten in demand. A few yards of «Y ir^, n o t the B b urtc d e fla wTl’rm a ako Ut 'a earth The S-kia-sss tlwnsg underneath tho aerial if possible, but this is not at all essential. COMBATING STATIC. Static is always wth us, that type of interference which sounds like a ton oi coal being 0 dumped. So far no real solution has been found for static, elimination, although some methods now m use mini mise its effects. The loop is one of these devices, and for that reason loop sets will not pick up as much static as an antenna set. As much of the static originates in the tropica or north of New Zealand, the directional properties of the loon will aid in reducing this source of trouble, due to the fact that the loop receives best in the plane in which it is pointed and poorest from sections at right angles to the loop. From this we can see that if the loop is pointing east and west most of the static originating in the north is rejected, and the Australian stations come through with great volume, while stations in the south and north are not received. A. shifting of the plane of the loop will shift the direction of greatest response. INCREASING SELECTIVITY. To increase the selectivity of a onetube set or a set which consists of a detector followed by low-frequenoy valves a simple method which should appeal to many is available. Insert a variable condenser in the aerial circuit between the aerial lead and the aerial terminal of the set. A switch should be connected from the moving plates to the stationary plates of the condenser, so that the condenser may be short-circuited, and the Pham tuning circuit used as heretofore. When the switch is opened the newly-added tuning condenser is in circuit, and. by reason of the reduction of aerial damping, which it effects appreciably, increases the selectivity of the receiver. AERIAL FOR THE SUBURBS. Under average conditions in a suburban district an outside aerial, consisting of a single wire approximately 80ft in length will be found most satisfactory, and it is recommended that this size aerial, be tried by all persons installing a receiver for the first time. If it is found that interference cannot be overcome by manipulating tho tuning controls of the receiver, it may be necessary to reduce the length. However, it should not be shortened any more than necessary to eliminate the interference. On the other hand, if no trouble is experienced from interference, the sensitivity of the set may be improved by adding to the length. When erecting this aerial every effort should be made to see that it does not pass near to any object which would be apt to absorb electrical energy. The lead-in wire to be used in connection with the antenna may be from 15ft to 20ft in length, thus making the over-all length of the aerial and lead-in from 95ft to 100 ft. WIRELESS IN SCHOOLS. In London alone it is reported that no fewer than 1500 schools are now fitted with wireless sets, and for these the British Broadcasting Company has been providing in ever-new ways that are generally evolved from the suggestions of school teachers themselves. The new Wireless Board includes in its personnel perhaps the most energetic brain in England —that of Dr M. J. Rendall, —and his presence on the controlling authority guarantees a vigorous future for wireless in the schools of the Old Country. If, then, wireless has been found beneficial in the schools of densely populated London, how much more so could it be as a means of bringing knowledge to the children in the sparsely-inhabited country districts of New Zealand? IN THE COUNTRY SCHOOLS. Throughout the countryside there are scattered little schools that deserve more attention than they sometimes receive. This is no one’s fault—they are merely isolated; nevertheless, they are educational outposts in which the future citizens of the Dominion are being trained for the battle of life. In the part-time school, or the school of few scholars and many grades under one young teacher, the children -are at a disadvantage, no matter how efficient and resourceful the teacher may be, and it is in these that wireless would prove an immense boon. A problem with which the Education Department is continually faced is how to give some breadth of outlook to these little schools. Of course, it rests mainly with the teacher to stimulate the minds of the children under his care, and if he does not begin the process no one else can. It is therefore the keen teacher that wireless will help most by tapping the cultural resources of the larger centres to stimulate the education of the young minds under his care. The immense possibilities of the kinema have already been exploited for educational work, and where reality can be given to a geography lesson by films of a country and its industries there would appear to be no reason why the same lesson could not be made more real by descriptions of the economic and other conditions in that country, broadcast by an expert on the subject. Wireless is free from the many obstacles, such as time and expense, which preclude the kinema from being altogether an unqualified success, and its progress has been more rapid and decisive. Either takes

tlio place of teaching to a certain extent, but both certainly add enormously to the range of interest and illustration whicn the teacher may use. _ Now that the larger broadcasting stations, such as 3LO, Melbourne, 2FC, Sydney, and the Broadcasting Company’s stations at Auckland, Wellington, and Dunedin are making a feature of educational talks at their daily sessions, it is not difficult to visualise the immense boon wireless could be to the children of the isolated bush schools. These youngsters hear the same teacher’s voice day after day, draw only on one man’s experience of life, and are influenced principally by one outlook and one point of view, and it is for them that wireless can do most. There are few schoolmasters or mistresses who are fully qualified in all subjects. One of fine literary gifts is just as likely as not to be weak in Nature study, and a born naturalist may find literature a trial. Similarly, any teacher not exactly built for it is apt to find the teaching of physical “jerks” somewhat of an ordeal, and there are others who, although competent in most respects, suffer painful humiliation when taking a singing lesson. It is to these that wireless will restore peace of mind and the balance of efficiency. The non-literary teacher will feel easier if, once a week or so, the children can spend an hour with a competent enthusiast exploring the masterpieces of the English language, and though it might be difficult to find a man or a woinan who.could choose literature that would inspire children and make it live for them, there is no doubt that, given sufficient encouragement, any cf the broadcasting companies could, and would, do it. There should be no need to make these talks entirely formal; but what joy would the mechanically-minded schoolboy derive from, say, an intelligent and forceful reading of Kipling’s ,f Ship That Found Herself,” and how would the drabness of a long school day be relieved by a scene from "Treasure Island,” properly read? And all the time, sub-consciously. these children would be having instilled into them a love and_ an understanding of this literature. As with good poems and prose, so it would be with music, and many a child who lacked the opportunity or the money to learn to play an instrument, could be taught by ear to detect aiyj appreciate the effects of the great classical compositions. Here again, the broadcasting companies can step in, and employ >n their studios those qualified to command the attention and quicken the enthusiasm of the children, and, at the same time, illustrate their lectures with renderings of the pieces under discussion. Then, again, how the young people would appreciate hearing from an engineer the story of the construction of the great Kawarau dam, or the erection of a lofty viaduct. They could be told by the men who are building up New Zealand’s :n----dustrles what problems they have to face, and this would give them a pride in the industrial pioneers of their country. Educational leaders could tell the young folk just what New Zealand expects from them, what training she offers, and the opportunities she is holding out, A SOLUTION OF THE PROBLEM. The problem of using wireless in education would appear to Ibe possible of solution by co-operation between the Education Department and the broadcasting companies, A little is already being done, by the companies, and all of them are convinced that, if necessary, they could find suitable speakers on any particular subject the teachers might wish to develop. The teachers themselves could help, and their advice would be of the utmost value in framing a preliminary syllabus. In numberless ways, wireless can bring the crowded metropolitan school and the little outback school into touch with the finest minds of the country, All_ that is necessary is co-operation, and with this, it may yet be that the scholars at Blackstone Hill, or some such place, will be able to listen in to Paris or London relayed by 4YA.