RADIO AND ITS RECEIVERS

Sun (Auckland), Volume I, Issue 185, 26 October 1927, Page 14

RADIO AND ITS RECEIVERS

Conducted for THE SUN by C. M. Taylor, B.Sc., A.M.I.R.E,

BROADCASTING BY CHURCHES Quite the most interesting radio news is the proposal put forward by the Church of England to erect its own station and use it for purposes connected with the Church. The germ of this splendid idea has evidently developed and grown snce the broadcast of the Bishop of London. This service is following what is common practice in America, where churches have established their own stations from the beginning of broadcasting, and is also a recognition that radio has not the effect of keeping people away from the source of the transmission, but rather attracts to it many who would otherwise not be so attracted. If the proposals come to a definite conclusion, as it is hoped they will, the location of the station and its wave length will need to be carefully gone into. Nothing more detrimental to radio could be imagined by the seriousminded than the reception well mixed of two sermons, and the distraction so caused to anyone trying to follow one address would be sufficient to set back radio into the class of wonderful but rather objectionable features of this wonderful age. SELECTIVITY ON LOCAL STATIONS

The writer still thinks that improvements could be made at IYA, which, on a shielded six-valve set. is too broad to bring in 2BL and 3YA, and yet on the old 420-metre wave length there was with the same set no difficulty in getting 2FC and SCL. Matters should, be improved on the lower vave lengths, as the difference in kilocycles is greater, but unfortunately this is not so in results. It is granted that such a wave as is used with a D.C. plate supply is. sharp, but then why is it that we get interference more pronounced than it is in other countries? Without going into technicalities. such a fact, that sets do not give the desired selectivity in Auckland are pronounced satisfactory by men of world-wide name in England and America, must surely be weighed. The statement that such reasons are ludicrous has its parallel in the case of a certain man who got a voltmeter calibrated against a standard, and then, on reading his own battery, condemned the voltmeter because his battery did not read as high as he thought it should. The writer is in communication with one of the engineers of the R.C.A. on this matter, and hopes to be able to publish some data on this important subject. RADIO IN BRITISH SCHOOLS

Three thousand British schools are now equipped with wireless, in spite of what our Director of Education says. An article in the “Journal of Education” states that the time has come for the British Broadcasting Corporation to arrange an all-day programme for schools on a separate wavelength, and t.o use this wave-length for the benefit of more advanced students in various kinds of continuation schools at night.

The articles goes on to say: “The poorest agricultural worker can, and apparently does, afford his crystal set, thus coming into contact with the great world at his fireside. And what of his children? Are they using the head phones also? And, if so, what do they hear? Has their schoolmaster grasped

the potentialities of this new instrument, and has he yet installed a valve set and loud speaker in the village school ?”

Station 3LO has commenced its educational programme and is prepared to extend its activities as the demand grows. The community as a, whole is not yet prepared to spend on its schools what it spends on its amusements, but with the extensive use that is being made of radio as an educational medium will remedy all this and in the future the enthusiastic teacher will count radio as one of his most useful assistants. NOT PARTICULAR Captain Moller, of the American fivemasted schooner Thistle, now in Australian waters, says the Australian radio announcers do not consider the names of their stations of much importance. Out in the Pacific the skipper’s wife and eight-year-old son could pick up many American stations, IYA, Auckland, and 2FC, Sydney. The difference in announcing the stations of these two countries, according to the captain, is remarkable. Sydney stations, he said, just mentioned it quickly and casually, while American and New Zealand stations emphasised the name. In America, he pointed out, the name is half the battle.

“Most listeners are great enthusiasts and like to know when they are picking up stations a good distance from their homes,” he said.

Captain Moller picked up some Australian stations off the coast, but he did not know what stations they were. Tie knew they were Australian by the items broadcast. INGENIOUS RADIO ADVERTISING

We are all familiar with the various stunts to use radio as an advertising medium; in fact we have had such in New Zealand, and if all could be made as interesting as a series of lectures on motor-cars then many would welcome such an addition to our service, provided, of course, it gave additional times of transmission. A limited use is made of radio in Australia, particularly by the B class stations, but in America many of the stations rely on advertising to keep going, as there are no licence fees. From this country comes a choice piece of stunting. The station concerned had been providing a series of organ recitals which were widely appreciated by listeners. Following this series the programme for a certain time one evening was announced to be an organ recital. Listeners concluded that the popular series was being continued, and thousands listened at the appointed hour. They heard an organ recital, but not the kind they had expected. An enterprising patent medicine company, trading on the good name of the station, had leased the station for that evening and the programme consisted of a recital of the organs of the body, which it was claimed would be benefited by using the company’s products. * PORTABLE-SET CULT

Portable sets have been produced during the last year or two in practically every country boasting a radio industry, but it has been a feature of these sets in England, at any rate, that their portability has been the Least of their attractions. After an initial period of work on the wrong lines,

most of the manufacturers found that the production of an easily mobile receiver, gi/ing ample volume and range with the purity of reproduction, equal to that obtained from a stationary receiver, was practically out of the question.

In the first place it was found that at least four or five valves were necessary to give satisfactory reception on the small enclosed frame aerial most of the sets embodied, and that alone meant quite a considerable weight of components. Then it was found that skimping the B battery supply produced markedly inferior results, while, in addition. a built-in loudspeaker was found to be a necessity, if such sets were to sell at all. The result has been, of course, that the most efficient types of “portable” sets are those with a weight of between thirty and forty pounds —rather more, in fact, than the average person desires to carry far when picnicking. In spite of these facts, however, the popularity of what are better termed “transferable” sets has consistently increased, until at the present time in England practically every maker produces two or three models of portables, while upwards of a dozen firms make nothing else. And the secret of the whole thing is that, while not easily portable, these sets can be carried about from room to room in the home; in the car when touring, and with the luggage when on holiday.

NOCTO-VISION As is well known, the Scottish inventor, Mr. J. L. Baird, is within reach of perfecting: apparatus, enabling moving images and scenes to be transmitted and received either by wire or radio in exactly the same way that sound is now transmitted and received. For some time Mr. Baird worked on a system involving the use of intensive light at the transmitting end, in order to make the image at the receiving end at all intelligible, but he found that in addition to being unsatisfactory this system is not the best. His latest achievement is to design and work apparatus whereby any object can be transmitted in almost total darkness. The secret of this development is the use of infra-red rays, and, almost as a natural sequel, it has led to a furtb discovery; nothing less than seeing in the dark. The scope of this latest invention is almost limitless, but its applications include seeing objects at a distance through the densest fog or in total darkness, which would be of immense value both in peace and in war-time, particularly at sea. The title given by Mr. Baird to this new discovery is “nocto-vision.” NEW APPARATUS A new chielded valve has been brought out in England by the Mar-

coniphone Company. It has among other interesting characteristics an amplification factor of 110. The main feature of the valve is the fact that the inter-electrode capacity, that quantity which necessitates balancing in tuned radio frequency amplifiers, is : entirely overcome.

A fine-mesh grid is placed between a standard-type grid and the plate, which is a flat circular plate with dished edges. The grid and filament are supported at one end. and the plate and screening grid at the other. The valve is mounted in a special holder horizontally and fitted with screening boxes so arranged that the partition dividing them is in the same place as the screening grid. The partition is earthed and the screening grid is connected to the B battery to form a complete electrostatic screen. Two new speakers have arrived in Auckland, and in their classes are unique. The first is the Octocone. a speaker giving remarkable quality and unique in being designed by one of America’s leading musicians. The other, the Raleigh, is in a cabinet measuring about 3ft. by 3ft by 2ft.. the sound coming through a handsomely designed Gothic arch. The speaker is of the horn type, paper mache in construction and of an overall length in its coils of about 10ft. THE SUN writes that it was unable to overload the diaphragm, and such quality is rarely if ever heard outside the original source.