Over the Aerial

Auckland Star, Volume LIX, Issue 254, 26 October 1928, Page 18

Over the Aerial

(By "PHONOS.")

WIRELESS NEWS FROM FAR AND NEAR.

The bi-centenary of the birth of Captain James Cook will be featured from 2FC at 9.52 this evening.

Excerpts from "II Trovatore" will again be presented by Madame Ainsley's concert party on Tuesday evening.

At 9.30 to-night "Madame Pompadour'' will again be broadcast from Sydney. 2FC will relay tlie first act, and 2BL the second and third.

Creeping back! The total of licenses for the Dominion last month exceeded 41,000. Of this total nearly 1400 were licenses held by radio dealers! The listener is not the only optimist.

In a Southern paper a writer offers a useful suggestion. It is that the silent night at each of the New Zealand stations should be abandoned, and that, per medium of records, a dance programme should be provided.

The Mussolini touch in radio: An official order in Italy decrees that musicians and singers must broadcast when requested. There are artists in some countries who were better placed under a decree of prohibition on the air.

It is highly probable that the Armistice Day service at the London cenotaph will be broadcast on shortwave by SSW. If that is so 2BL will endeavour to rebroadcast the service on its ordinary wave. Such rebroadcast3 should be audible in New Zealand from 11 p.m. on the 11th.

An historic occasion affords a chance for a novelty relay within the next few days. "Guy Fawkes" will soon be with us. Stations in other parts of the world have used his time-honoured anniversary as a means of providing an acceptable novelty. Is there any chance of IYA getting a line to a well-staged bonfire and cracker scene?

Reception conditions during the past few days have swung to absolute extremes. On Sunday and Monday any attempts to reach out for distance meant torture. Static was at its vilest, and was noticeable even on local broadcasting from IZB. Tuesday brought a marked change, and by Wednesday evening conditions were well nigh perfect.

An argument in favour of the use of records in broadcasting: A good radio set and loud speaker will reproduce broadcast gramophone records with incomparably better tone and more realistic acoustical effect than the average high-grade gramophone. Therefore, the broadcasting of grand opera records creates far greater pleasure for listeners who have good radio equipment.

Cricket does not offer the scope for broadcasting which is afforded by football, but the forthcoming matches of the English eleven in Australia will be given due attention by broadcasting services. To-day UT/O will be describing the game against South Australia at Adelaide, and possibly short-wave accounts, which will be audible in the Dominion, will also be transmitted for the benefit of English listeners.

Some weeks ago it was mentioned in this column that a new station (7LO) was being opened at Nairobi, East Africa, and the announced wave length was given at 90 metres. Seemingly this has been changed, for 7LO has been picked up clearly by Mr. F. W. Sellavs, of Northland, Wellington, on a wave of 33 metres. Reception at about 5 a.m., which was about 10 p.m. on the previous day at the transmitter, was quite clear.

It is pleasing to note that the Auckland station is offering prizes for locallywritten radio entertainment. For a long time now the encouragement of resident literary and elocutionary talent has been advocated in these columns. It is to be hoped that the new step meets with the support it merits. Quite a fine New Zealand "atmosphere" can be created by our radio service if the talent available is fostered. We have given our Maori a good show; now comes the opportunity for talent tlia? exists and requires only fostering.

Wclcome variety is now being introduced into the programmes at IYA. On Thursday next a debate will be presented, the subject being "That the modern girl is an improvement on her grandmother." As more modern girls than grandmothers will be listening, there is no doubt as to how the vote of the unseen audience would go. On Friday evening we are to have an evening of old-time nigger minstrelsy, an offering that has been found very popular across the Tasman—so popular, indeed, one wonders why it has not previously been fully exploited here.

Summer is with us—for perhaps an hour or two daily. Overseas reception on the broadcast band will wane in attractiveness as the days lengthen, but an avenue too little investigated by the majority of listeners is available for almost any valve-set owner. We are on the threshold of the era of short-wave transmission. To the big majority of listeners this means little, for not many realise that the ordinary set is easily, cheaply and quickly convertible into'« short-wave receiver. Suitable adapter? are procurable at quite moderate prices and through their attachment. .English programmes may be heard at. breakfast time, with little of the interference that marks ordinary summer reception. America, Holland, are developing short-wave programmes.

A LITTLE ATTENTION.

It is simple enough to keep the radio receiver in top-notch shape. Just a little attention from time to time will maintain the set as a source of real satisfaction to the household. Radio is your window to the outside world, and what is more natural than to keep the window clean and bright for the sunshine that conies through it? Dust is the enemy of radio efficiency. It gets into crevices and between vital parts of the receiver, resulting in leakage and consequent noises, especially when there is excessive moisture. So every once in a while the radio listener should go over the working parts with a soft camel-hair brush which will reach into tight spaces. A soft cloth may be used to wipe off the cabinet and panel. Loose connections are fatal to clear reception. Often static or atmospheric conditions are blamed for scratching sounds and rumbles that are due to loose connections between receiver and ground or aerial system, or in valve sockets. Occasionally *.he owner should go over all connections, making sure they are tight, or should obtain the assistance of'a radio firm that specialises in "service."

NOISES!

A correspondent inquires as to the cause of pronounced scraping, scratching, and knocking sounds emanating from his set through his loud speaker. The inquiry opens up a big field for investigation, as so many causes lead up to tlie effect. It is to be assumed, for a commencement, that the correspondent is satisfied that old man Static is not the cause. Static has been so persisitent of late that newcomers *o tlie ranks of radio can be excused somewhat for blaming the set rather than conditions beyond human control. Speaking generally, noises such as those complained of can most commonly be traced to two causes, i.e., defective batteries, A or B, and defective wiring. A batteries as a rule do not give much trouble except recharging; but occasionally when a cheap accumulator lias been in use for some time the insulation breaks down and internal shorting occurs—hence the noises! In going about the testing, do the job methodically. First remove aerial and earth wires, start the set, adjust to full volume, and see if the noises continue. Assuming that silence reigns, examine carefully the two wires, removing any frayed ends. In the case of the earth wire see to it that the connection with the water-tap or other ground is electrically clean and firm. Examine the lead-in of the aerial. If tlie lead-in has been soldered to the aerial, pull down the aerial and resolder. Nine times out of ten aerial troubles arise at this source. Perhaps, however, the aerial and earth connections are good. The next step, then, is to examine the B battery. The life of a B battery, of course, depends upon its use, and it must be remembered that when a 45-volt battery drops in its rating to 35 or volts it is by far the best practice to discard it. The cells hold their voltage for a considerable time at first, and the fall to about 35 volts is very gradual. After this point is reached, however, the voltage falls very quickly. Internal reactions and decomposition take place, and these effects give rise to crackling, frying sounds very much resembling phenomena ascribed to static. There is no real economy in using B batteries which have dropped beyond the voltage mentioned. Tone is distorted, whilst volume falls away. Whilst on the subject of batteries, see to it that all connections are clean, unbroken, and firm.

Next test all internal wiring connections. Examine every soldered connection critically, resoldering where thought desirable, and tightening up all other connections. It very frequently occurs that joints apparently firm in reality are only flux held, losses occurring as a result. Passing on, examine the rheostats and switches very carefully. Poor components and loose connections will give the trouble complained of. Other contributing causes are faulty transformers, coile of all kinds intermittently making connection and breaking again, valves not making good connection with the valve sockets, dirt on valve frongs or valve sockets. Dust gets between the plates of variable condensers, so partially short-circuiting them, or the plates may be touching in places. In the former event clean with a pipe cleaner; in the latter event carefully bend them back into proper shape. The grid-leak may have broken down. The grid-leak is intended to allow the charges on the grid to leak off slowly. If too high, the charge collects and makes the grid too negative, thus stopping the action of the valve. The cure, of course, is to test with various grid-leaks until the best one is obtained. Sometimes the plate lead touches the - grid leads or runs close to tlieni. This results in a feed-back either by aetual contact or by capacity effect. Separate the leads. A defective jack or phone plug will also give the noises complained of. Finally, closely examine the speaker terminals and cord, together with the unit.

From all this it will be Feen that the diagnosing of unwanted noises is quite a complicated business, entailing the exercise of unlimited time and patience, and really the best way of doing it is to send the set to one of our advertisers on this page, who can be relied oil to put the matter right quickly, thoroughly, and cheaply.

BRITISH RADIO PROGRESS.

Big reductions in the price of wireless receiving sets were the feature of the Radio Exhibition in London last month. Complete sets- were generally 25 per cent cheaper than last year, and in some instances a still greater drop in price will be noticeable. These reductions are attributed tJ the recent decision of the Radio Mauufacturers' Association regarding valve royalties, and also to the stablisation of design, which facilitates mass production.

Three-valve sets, giving a performance equal to that of the old-type five-valve sets were exhibited. This important development has been made possible by the manufacture of the new pentode, or live-electrode valve. Last year the screened-grid four-electrode valve effected a revolution 011 the high-frequency side of receiving apparatus. The pentode has accomplished a similar feat on the low-frequency side.

Excellent loud-speaker reproduction can now be obtained from a set incorporating one of these new valves in the last stage. The pentode is, in fact, probably equivalent to two ordinary low-frequency valves, and it works on a low plate-voltage for a valve of the super-power class.

There were more sets tlian ever drawin? both high and low-tension supplies from the house-mains. Refinements in valve design have made possible distinct advances in the quality of reproduction from sets of this class. Listeners without electric light mains will find that accumulators and batteries are cheaper and better. There was also an interesting device for the benefit of car-owners, by means of which accumulators may be charged from their lighting sets.

A short-wave set incorporating a highfrequency stage is another noteworthy feature. Several manufacturers are exhibiting sets which arc not only efficient 011 the ultra short waves, but als.o giye good results on the medium and longwave bands. 'It is* fin indication that* short-wave listening will not in -future be confined to.the experimenter. Cheaper-coil-driven loud-speakers will also attract attention, as well as the improved reed-driven cones and horn-type speakers.

As usual the 8.8.C. had an interesting exhibit in preparation. The chief part is entitled, "From B.C. to 8.8.C.," and comprises a series of tableaux. In these were shown how mankind had listened to music from the earliest times to the present day.