Radio Review

Evening Star, Issue 19942, 11 August 1928, Page 18

Radio Review

Flashes from Everywhere.

—[By “HENRY.”]-

RECEPTION LATELY. Following are a few notes on distant reception generally during tho last fortnight:— JOHK Japan has been coming in pretty well at times. By the way, one announcer at this station gives the call sign quite plainly, while another seems to pronounce it JO(AITY)K, making the H into A and T, running the two letters together. The Australians have been up and down, so to speak, 4QG being the most consistent. 3LO, 2BL, and 2FC have all been fairly good early and late in the evenings, but not worth listening to round about 10 o’clock. American stations have not near been up to standard. Last Saturday FCJJ was at its best about 4 o’clock, but gradually faded until at 6.30, when music was just audible on the speaker. The announcer called up several New Zealand and Australian listeners and thanked them for reports. As one listener put it, “ SSW fizzles out after 9 a.jn-” Taken all round receiving conditions have not been very good, and fading has been noticeable. 8.8.C.’S FIRST REPORT. A complete review of tbo work _of the British Broadcasting Corporation and the finances during 1927 is contained in the corporation’s -first annual report. The report states that the regional scheme comprehends the erection of a limited number of high-power twinwave transmitters to replace the present comparatively largo number of low-power stations. Tho areas served can no longer be extended by erecting more stations in view of tho_ restricted number of wave lengths available, and ilio inevitable interference between home and foreign stations. In general, tho present system restricts listeners v idi simple apparatus to tho reception of one programme. Under a plan draw n up by the Office International do Radiophomo Great Britain has the use of ten wave lengths, and tho regional scheme is designed to supply Ihe maximum advantage from them by giving the greatest possible number of listeners an uninterrupted service of two programmes. Transmissions from all stations covered over 63,000 hours in 1927. Entertainment naturally formed the bulk of all programmes, bit there was a strong and growing demand for other features. Special attention was paid to the technique and presentation of programmes as a whole. Considerable advance was made in adapting existing forms of art to _ broadcasting. There was a duo proportion of familiar works, but many first performances were also given, and, in addition, music and plays were specially written for broadcasting. In all parts of the country full respect has been paid to national and local sentiment and tradition, and local resources _ have been drawn upon where _ suitable. Music formed about two-thirds of all programmes. The corporation carried oh the annual Promenade Concert Season in the Queen’s Hall, which would not otherwise have taken place. Educational work, as a feature _in broadcasting, gained steadily in_ importance and in popularity. This is of two kinds—broadcasting for schools and built educational broadcasting. Approximately 4,000 schools were known to listen to London and Daventry schools transmissions alone, this being double the number for the pire history. For secondary schools courses were broadcast in music, English literature, French, nature study, geography, social history, and Empire hiestory. For secondary schools courses were given in anthropology, elementary geology, _ international affairs, and biographies of literary men. The Kent Education Committee undertook an inquiry into the efficacy of schools broadcasting, with the assistance of a grant from the Car* necie United Kingdom Trust. The report of this inquiry, when received, will deal with the educational possibilities and present practice of broadcast lessons in schools. Approximately 1,500 adult education bodies co-operated in tho distribution of tho sessional talks programme. Adult education talks veio usually arranged in a series of cither six or twelve, the subjects including history, economics, social science, philosophv, biology, and astronomy. In addition to tho programme of talks and lectures, whose circulation reached 60,0(10 copies a session, aids to study pamphlets containing notes, illustrations, book lists, and summaries of lectures were issued. The total number of these distributed during 1927 was 193,000. In addition, many of the adult courses were followed by small discussion groups started in various parts of the country. These experiments proved extremely promisinThe financial policy during 1927 was determined by working policy. the regional scheme naturally _ bulked largely in the considerations involved. Estimates were drawn up of the probable income of tho Corporation for 'some years ahead, the cost of erection and equipment of tho proposed regional stations, and of financing tho scheme by and tho increased costs of programmes and engineering maintenance. total revenue expenditure is £li 3,-89 10s 8d to which tho expenditure under the various headings bears the following approximate percentages: Expenditure on programmes, bd.U/, maintenance of plant, power, etc., 10.95: rents, rates, insurances, etc., 8.18. administration expenses, O.oS, provident fund contribution. 1.U2 governors’ fees, Q-79; provision for depreciation, 3.41.

because its output is not confined to so narrow a frequency band. This typo may be worked with a power valve (a D.E.P. 215. for instance) biassed to 9 volts with 100 anode volts. It is strongly advised, however, never _to push the valve much beyond these limits if tho best quality of reproduction is to be maintained and a reasonable life to be expected. Tho reed-driven cone typo of loud speaker is better able to deal with low notes than is the typo just mentioned. It possesses a comparatively level response, not accentuating those notes that dominate over tho others, and consequently it may be permitted to handle a greater output than the domestic horn type. It will be found that its most effective range is when driven by a super-power valve of the D.E.SA. typo, biar rcl to 15 volts, with 120 volts on tho anode. These figures, however, are not arbitrary, for individual specimen of the same-pattern loudspeaker frequently differ quite appreciably in regard to the amount of power they can best take. TELEVISION SUCCESS. Although much publicity has been given to efforts being made iu Great Britain to r -feet a system of wireless television, comparatively little lias boon heard until fairly recently of the experiments being made in America. A striking television demonstration was given recently by Dr E. F, W. Alexanderson, one of the consulting engineers of the Radio Corporation of America, and one of tho best-known wireless engineers in tho world. Tho transmitting apparatus fsavs an Australian (paper) was applied to two broadcasting stations in New York. One of tbo stations transmitted the moving pictures, while the other transmitted tho voices of those whose images were “televised.” Tho receiving instrument resembled an ordinary cabinet gramophone,_ the imago being reproduced in a “window” about 3in square. According to reports on the experiments, the received image was so clear that tho curl of smoko rising from a cigarette and tho Hashing of an eye could bo seen in tbo receiver screen as clearly as would have been possible in the studio some miles away. Leading American engineers, while admitting that a great deal of work is still necessary before television sets can bo used in tho homo as easily as broadcast receivers can be, take a more optimistic view of progress than that expressed by British scientists. In Great Britain the opinion is steadily growing that, while existing television methods have been successful up to a point, the limit, to which they can be developed is fast being approached, and when it is reached the apparatus will still fall far short of the requirements for a practical system. It is believed that some entirely now scientific discovery will be necessary before a really practical television system can be built up. These views, as tbo considered opinions of leading British scientists, cannot bo disregarded, but it is nevertheless encouraging to hear such an authority as Dr Alexanderson speak optimistically of the future of television. STATION RIVALRY. What promises to bo a keenly coK' tested fight between “A” and “B” class stations in Ausralia lias commenced. Conferences of owners of “ B ” class stations have been held in Sydney, Melbourne, and Adelaide. It has been decided to form an organisation in each of the States for the protection of the interests of “ B” class stations (states a writer in tho Sydney ‘Morning Herald’). These State organisations are to bo linked up into an Australian Federation of “B ’ Broadcasting Stations. The objects of tho federation aro stated to bo;

1. To co-operate iu the co-ordination of broadcast programmes from “ B ” class stations, with tho object of rendering better service to the listening public. 2. To protect and advance tho interests of “B” class stations generally. 3. To co-operate with “ B ” class stations in other States for the above objects.

Proposals havo been submitted to the Now South Wales section of the federation for a co-ordination of programmes so that the different “ B ” stations will not bo broadcasting simultaneously the samo class of programme. At the present time the “ B ” class stations in Sydney represent in the main sectional interests. The Trades Hall runs 2KY in the interests of the Labour movement. 2GB is owned and controlled by the Theosophists, but devotes a great portion of its time on the air to entertainments and advertising. The Roman Catholic Church authorities have leased 2UE for the broadcasting of its own news, and more particularly news of the forthcoming Eucharistic conference. When not being used for this purpose 2UE broadcasts music and radio trade information. It is understood that the Roman Catholic Church as a body, has under consideration plans for the establishment of a broadcasting station which will be owned and administered by the church authorities. No definite decision on this matter will bo come to, it is stated, until after the Eucharistic Conference in _ September. 2UW has been purchased, in trust, for a new company, and important developments are anticipated at that station in the near future. It is claimed on behalf of tho B ” Federation that tho merit of the programmes they are daily putting on the air entitle them to participation in a portion of the revenue from listeners’ licenses which is at present distributed, in pre-arranged proportions, amongst the “A” stations. A petition to that effect will, it was stated yesterday, bo shortly submitted to the PostmasterGeneral. in tho alternative it will be requested that the Post Office Department limits the right of broadcasting advertisements to the “ B ’’ stations, and make it obligatory on the “A” stations to refrain from putting paid publicity, either directly or indirectly, on the air. RADIO AT SEA. An auto-alarm has recently been installed by Amalgamated Wireless (Australasia), Ltd., at the A.W.A. radio station at Suva Fiji, the first to be installed on land in Australasia or in the Pacific Islands. The auto alarm at Suva comes into operation on the closing of the station at midnight (states an exchange). The pre-arranged signal is strictly confined to use as a preliminary to the well-known “ S.O.S. signal, and has the effect of attracting the attention of the telegraphists, who, though off duty, are on tho premises, and in calling them to the operating room by moans of tho automatic ringing of bells. One of the bells is located in the operating room, and the others are placed in tho bedrooms of the telegraphists. All the bells continue to ring until attended to and switched off in the wireless room by tho operator, who then takes up a watch for the vessel calling. The best pre-arranged signal has been found to bo a scries of dashes, each of four seconds’ dura-

GRID BIAS. Tha nonular estimation as to A' 1 ® amount^of negative grid bias required to the last valve of a receiver varies immensely There are, of course, man' lac Tors involved, such as the type of valve, the type of loud speaker, the volume required, and so on; consequently, the following general suggestions might prove helpful to teadeis. Tho factors that wo Mill tako into consideration being the two most essential, are the type,of loud speaker and the volume required to till an averagely-sized room. There are on tho market many small horn types of loud speaker which amount to very little more than a trumpet fitted to a headphone-rough, but to a certain extent, effective. It will bo found that the majority of these develop most of their energy within n frequency band of from 1,000 to 2,000 cycles per second, which, so it happens, coincides with the note-pitch to which our ears are most sensitive. Consequently this typo of speaker requires very little input tc bo effective. Tho large domestic horn typo of loud speaker, while it, does not give much mors bass than its younger brother, qotmds considerably better, principally

«Henry - will pe pleased to omwei anj question? through this column relating to tho fascinating hobby. £«h oomspondent must alga bk noma and addrw (not necessarily for publication). Newsy items will be welcomed.

tion, separated by intervals of one second, and to this combination the name of “ arm signal ” has been given. The auto-alarm equipment consists of two chief units, the receiver and the selector. Tho receiver comprises a three-valvd amplifier and tuning circuits so arranged as to cut out as much as possible signals on wavelengths other than 600 metres, and at the same time to be fully sensitive to any wave within 2J per cent, of GOO metres, the limits of error which aro now allowed to the tuning of ships’ transmitting instruments. Signals from the receiver are passed on to the selector, whose duty it is to pick out tho alarm signal from all rther signals or mixture of signals which may be received. The peculiar arrangement of the selector, combined with the nature of the alarm signal, enables the apparatus to pick out t’.c alarm signal even when the ships are sending Morse messages at the same time and on the same wave-length, however close they may bo, AN AID TO MINING. In more than one Canadian mining area now' one may hear tho cry “Line,” and in the distance tho answer “ 0.K.,” followed, after another short interval, by two whistles and the “Off.” Radio has gone prospecting, and tho old order is changing. Radio has been tried successfully in the Southern States in locating ores, and has now been introduced in Canada. Tho equipment consists of a transmitter—a big tripod loop with water levelIcrj fo. working on uneven surfaces—and a receiver. It is operated by a crew of four men. The transmitter is set up, and tho receiver is taken from place to place. It is'pointed at loop, and tho signals are checked to zero. Tho call “ Lino ” is to tell the operator at the receiver where to focus on the loop. “ 0.K.” and two whistles are to check report. When these arc received the transmitter which works on a wave-length of 3,000 metres, is turned on. The signal is picked up from tho electrical conductors underground, which aro sulphide-boaring ore bodies, and which re-radiate the signal to tho receiver. The angle of tho signal having been obtained, tho receiver is moved to another location, which shoul I show another angle. These angles constantly grow smaller and smaller, to zero, and, when that is reached tho receiveroperator checks the location by converging on it from the opposite direction. If zero is again proved, the location is over a sulphide-bearing deposit. Depth is ascertained by signal intensity. Should a number of zero spots be located at different places in the same area, and no signals are shown it is due to tbo fact that there is no electrical conductor underground to re-radiate the signal. Tho apparatus does not identify the nature of ore body; this must be proved by drilling. HERE AND THERE. Local listeners have already had a taste of tho WilHamson-Melba Opera Company, when Stations 2FC and 2BL took turn about in relaying one of the operas on Tuesday night last. The former station was tiio better of the two, as far as Dunedin was concerned, and the whole relay was very much appreciated by those who listened in. Station SSW, Chelmsford, was closed for a while this week whilo alterations were carried out. Has anyone found any trace of RIM, tho Russian short-wave station, lately? Ho seems to have left tho air for a term. A crystal set built on a tooth brush was recently shown in New York. This set, although small, :tairly bris.tled with good point Several m i/ types of valve aro likely to be paced on the - English marnet about September. One prominent valve-manutactunug firm is making a live-electrode valve for Jow-frequeucy work, and it is claimed that this valve will givo a greater amplification than tliree ordinary valves. This five-elec-trode valve is not of th= toewe typo, which includes all the apparatus tor tho two stages of resistance-capacity coupling. British East Africa’s first broadcasting station has just been opened, it is situated in Kenya, a few miles out of Nairobi, the capital of tho colony. This enterprise was locally p romoted and financed, Lord Delamere, who lias lor many years been resident in East Africa being chairman of the company, am. Commander L. Mansfield Robertson, a naval airman, is tho manager. Kenya is tho third British colony to operate a short-wave broadcasting station.

4ZM is off the air temporarily while alterations are being carried out. Howlers continue to make their presence felt, much to the disgust of other listeners.

Thera was a big clean-up of radio pirates in Sydney recently, when 1,176 persons were fined a total sum of £2,180 with costs totalling £742. In an English sea town a broadcast relay service has been organised, and 300 subscribers listen to the London and Daventry programmes. There is a central receiving station from which lines are run to tho houses of the subscribers who provide their own loud speakers. The subscription is Is 6d a week, in addition to the 10s license fee. It is announced that the Commonwealth Postmaster-General has shelved Sir Bon. Fuller’s application to establish an A cl,ass receiving station in Sydney until July, 1929, when 2FC’s license expires. The whole situation will then be reviewed. 2FC is in receipt of any inquiries concerning “Mike,” who has not appeared at that station for some time. Listeners want to know if there is a likelihood of “Mike” reappearing. CORRESPONDENCE. “Listener” (Dunedin) writes: On my broadcast set and on my short wave set I got 4YA in about thirty different places. Are these short wave transmitters, and, if so, what are their real advantages? 4YA does not have thirty transmitters, nor are there simultaneous broadcasts; What you have heard are harmonics.