RADIO AND ITS RECEIVERS

Sun (Auckland), Volume II, Issue 355, 16 May 1928, Page 16

RADIO AND ITS RECEIVERS

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

Notes and Hints

The use of copper palls on an aerial over 30 feet long causes lack of selectivity. * * * In Sweden nearly 350,000 licences had been issued up to March 31 last. This shows an increase of 20,000, compared to Chicago radio stations sold time on the air at the recent elections at the price of £2 a minute. What a chance for the New Zealand Company next elections. When a wave trap is used with a direct coupled receiver of the Browning Drake type, the neutralisation is affected. A trap should not be connected permanently in circuit, but should always be easily removable with a shorting switch. * * * Africa has caught the radio craze and Arab chiefs are purchasing the latest sets, so that they can listen to European stations. It is said that the London station is favourite, and that jazz music pleases these Arabs very much.

Caps of head phones should always be screwed up tight to avoid rattling in the diaphram.

The C battery being merely a potential device and passing no current, has practically its shelf life.

A British newspaper writer points out that the twin flex used for loudspeakers makes a pretty trimming for ladies' hats. In other words, it will suit all kinds of loud speaker.

The English market is making great provision for the amateur constructor in the way of home-built loud-speak-ers. The Brown kit complete is already }n Auckland, and one of the moving coil type the “Peerless” as used by the of Wales on his Calgary ranch, is due here shortly. The English magazines are full of advertisements of these kits ranging in price from a few shillings to several pounds.

American taste in radio music is much higher than is usually supposed. In a questionnaire recently circulated Beethoven was the favourite composer, and the overture to “Tannhauser,” by Wagner, was given first place in the musical compositions, with Suppe’s “Poet and Peasant” second.

Radio in China is going ahead rapidly. A short wave station has been built at Nanchang, and a broadcasting station is being constructed so that lectures and news may be broadcast daily.

It has been announced this year that the British postal authorities expect to pay the 8.8. C. something like £BBO,OOO. There are about 2£ million licences in existence and it is estimated that they are being added to at the rate of 1,000 a day.

Has any short-wave enthusiast heard the Chevrolet caravan shortwave transmitter, 20 and 40 metres, daily at 4 a.m. G.M.T., and repeated at 12 p.m. G.M.T.? This caravan left Capetown and on March 22 was crossing the Simpopo River in Rhodesia, on its arduous trip from Capetown to Stockholm, in Sweden. * * *

The King of Afghanistan, who has been so much in the European eye lately, is keenly interested in radio, and has taken every opportunity of visiting the various big stations in his travels. He proposes a most extensive use of radio, both commercial and broadcasting, on his return to his country.

It is extrelnely difficult for Wellington listeners to hear'4YA while 2YA is transmitting, owing to their proximity in wave-length. In many cases, however, it can be done without a trace of interference by tuning in 4YA’s strong harmonic (about 231 metres). This is easily done on a receiver of the Browning Drake type, and good loudspeaker results are obtainable. 4YA has always had very strong harmonics. They represent wasted energy, but on the special conditions here the waste is not complete. The writer often gets 4YA with better volume and clarity from the harmonic than from the fundamental wave.

Now and again there comes a particularly revealing glimpse of the manner in which wireless breaks down distance and time, and the enterprise of overseas broadcasting stations. A recent inauguration made by 2BL seems to illustrate this. Following the usual monthly Sunday night transmissions made specially for the benefit of overseas listeners, the station has now arranged to broadcast request items from American listeners. But the requests will not be made by the cumbersome method or letter or cable as arrangements have been made with an American short wave station, 6AE, to transmit the names of items the listeners may wish to hear. Thus, listening to 2BL in America, one has only to get in touch with 6AE, which will immediately send a message to Mr. Ray Allsop, 2BL’s engineer, and the item will be broadcast almost at once. * * * LISTENERS' HANDBOOK In the 1928 copy of the “Radio Guide” issued by the Amalgamated Wireless (Australasia), Ltd., wireless listeners W'ill find a mass of useful information. The book is the third which has been issued by the company. The publication can really be regarded as an Australasian wireless year book, because it comprehensively covers the whole field of Australian wireless activities. An interesting section is devoted to a description of the Australian beam wireless stations and the associated feeder apparatus. Applications of wireless to police work, to “outback” communication, to lighthouse service, and to the New Guinea goldfields are the subjects of interesting sections. Valuable information regarding the installation and maintenance of broadcasting receivers is included, while a comprehensive selection of circuit diagrams will be found of interest by the home constructor. The booklet contains information relating to the latest forms of receiving and transmitting equipment, find it is fully illustrated. FROM FRANCE The Metal Company of Paris has just introduced on the French market an indirectly heated A.C. valve, capable of replacing any ordinary valve in use. The characteristics of the heating element are 2.5 volts, 1.75 amperes. At a municipal election held in Paris recently, a candidate ran on a “Sporting and Wireless” ticket and found himself with about 100 votes at the bottom of the poll.

RADIO REPRODUCTION

DR. LEE DE FOREST’S OPINIONS NOT GOOD ENOUGH Asked recently, in an interview over the air from an American station, where the present day radio set fails, if it does fail, Dr. Lee de Forest, the noted scientist, said that the weakest link in the chain was reproduction. Receiving sets, broadly, do not give the quality which they should give. This was ascribed to several technical reasons, and principal among these was that sets and speakers for the most part were overloaded. Too much, in the way of volume, is expected of them, and too little attention has been given to the question of amplification. A radio set, to be thoroughly selective, cannot, theoretically at least, give absolutely distortionless music. Sharp tuning inevitably “cuts off the sidebands,” which means that all the tones are not received, resulting in an upsetting of the musical harmony, as would be the case if you damped some of the overtones from a piano note. And seldom is quality, in many things besides radio, compatible with cheapness.

It would seem, then, that the doctor has hit the nail on the head. But wireless still thrives; musicians with reputations to maintain consent to be broadcast—and own sets—and the people are undoubtedly better off, musically, than ever before. All this could not be possible if the average set delivered music of a definitely poor quality. The truth is that reproduction nowadays is so near to perfect that the difference hardly matters. Undoubtedly sets are overloaded, just as motor-cars and buses and trunk telephone lines are sometimes overloaded, but the ear, even of a trained musician, is not critical enough to detect the fault.

No sound, musical or otherwise, reaches us in perfect order. We listen to a band in the open air, and nearly always the lighter and higher-pitched instruments are lost, to the detriment of the musical balance; we hear the same band inside a building and reverberation interferes in another way. For the same reason we pick our places as carefully as possible at a theatre, for in some spots a singer’s voice will echo, or can only be heard Imperfectly. And we listen to a speaker at a public meeting, and for one of these reasons, or all of them, we are fortunate indeed if we hear every word—-or as much as we would on the speaker at home. And, not being sufficiently critical, we never know how much of the open-air band is lost, or how much it reverberates, or to what extent the singer’s voice echoes, before we are conscious of the fact—we put it down to the players and artists themselves. But the same fault, heard by means of wireless, would immediately be called “distortion.” It is hardly fair to expect a brass band of 49 players to sound perfectly natural in a small room, nor a singer with a “drawing-room” voice to be at her best in the open air—in one case, an undue softening must be effected, and in the other unnatural amplification has to be employed. But how many listeners make allowances for circumstances like these ? Thus, the bare labelling of wireless reproduction as poor is rather unfair. While it has its faults, necessitating efforts towards something still better, there are other deficiencies, probably outweighing those of the set, which is often blamed for’ reproducing music as it really is.

WHO IS 2YG?

2BL’S SHORT-WAVE STATION Every Monday morning between 4.30 and 5.30 Mr. Ray Allsop, chief engineer of Station 2BL, has been transmitting special programmes of music on short waves for reception in countries beyond a distance of about 1000 miles. Listeners in many parts of the world are picking up these transmissions, and a number have written lately informing Mr. Allsop that they are listening in. A New Zealand enthusiast evidently did not realise who was 2YG, as Mr. Allsop’s experimental station is called, for he wrote to Station 2BL to find out. Lately 2BL has been transmitting not only on the usual wave length upon which the station is heard by broadcast listeners in Australia, but simultaneously has been sending out the programmes through Mr. Allsop’s short wave station, for reception by listeners overseas.