RADIO AND Receivers

Sun (Auckland), Volume 1, Issue 89, 6 July 1927, Page 11

RADIO AND Receivers

Conducted jor THE SUN

By

G. M. Taylor, B.Sc., A.M.I.R.E.

----local news and notes

Listeners will have noticed that Elions are being- asked on the floor f the House of Representatives conSrnlng the broadcasting situation, and die replies are being eagerly awaited. THE A.L.L. Th> executive of the Auckland Listeners' League met last Tuesday and resolution was passed placing on record the league's appreciation of the Prime Minister meeting th«f president and secretary and assuring the Government of the league’s fullest co-opera-tion in the e ven t of the Government assuming control of this national server; and also expressing the opinion that such .control would have a most beneieial effect on the number of ]icen:es. It was also decided to take a referendum of all listeners In the Auckland Province, the result of which JriU be an eloquent reply to those few „ho are so completely satislied with the present service. SHORT WAVES A short-wave station in Ottawa has been coming in at good strength, making tests for an Empire-wide relay of Canada's diamond jubilee celebrations, which include a special carillon which will be set in operation by his Majesty the Xing, operating a relay from London. BETTER FARE COMING If this increased expenditure on programmes (which is current rumour) is wisely expended, listeners should be given a taste of what they have rightly considered to be their due for the last veai'. Auckland’s best professional artists should now take their place before the microphone at IYA.I THE NEW ANNOUNCER Tie new announcer at IYA is Mr. Cul:'ord Bell, a well-known teacher of elocution, a recent arrival in Auckland from Wellington. It is a pity Mr Bell knows only a little about music and also a pity to hail him as the new •'Uncle Jack.’ NEW WAVE LENGTHS The new wavelengths have definitely removed the actual interference be- . tween stations in Australia and New 1 Zeeland, and should give much satisfaction to everyone concerned. 2YA, in view of the opening in a fortnight's * * r:- -h -i-

time, will no doubt be heard testing very shortly, and many crystal owners are polishing their aerials and generally getting ready for the reception of 2VA in Auckland. Given good apparatus, a good aerial and earth, this station should be heard by many who to.ve hitherto been confined to the local stations. To those crystal set owners who hear Australia. Wellington should bo an easy prey. WHAT SPEAKER? Frequently one is asked, “What speaker do you recommend for me to use? or “Should I buy the Rattle' em Horn or the ‘Cough’ Cone?” This is one of those questions like: “Have you sopped beating your wife?” which cannot be answered directly without embarrassment. Leaving out the question that tastes differ to the extent that a speaker which is shown by every test to be an acoustical atrocity. will have its enthusiastic admirers, while a high quality reproduction is condemned as boxy or muffled, answer is not simple. The beluiviour of a speaker depends to a great extent on the amplifier with which it is used. • It might be thought that the effect •>f the speaker and amplifier are directly additive, that a good speaker will sound better on a poor amplifier than a poor speaker. Such does not prove •0 be the case. Some speakers are so poor that they are terrible with any amplifier. Between a great many speakers, however, the amplifier will determine the choice. A perfect amplifier will, of course, sound best with a perfect speaker, and generally speaking the better the amplifier the better ine speaker which gives the best results. A simple experiment will determine your choice. Get your dealer to arrange his selection so that each one may be cut in at choice. Tune to a station where the quality of the output is good, and the rest is easy. The choice will depend on the item being broadcast, as some speakers have much different outputs on different frequencies, and the test might well be carried over a number of stations where different types of programmes are being transmitted. Beauty, it is said, is in the eye of

or e thl hol< ? r ' so quality lies in the ear or the auditor— and lies and lies BROADCASTING AND THE SCHOOLS va?u n e 81 0? d r h ad S io alr as dy an eC °5 niSed the medium, and a educational the opportunity Of heartn'a n S,e SCh °v, 1S are masters of their who S S rfy°°t d TwXplies paT literature* and appreciation of H ™°”h te f rom e ?& £ fpecial made *every SS&:Tu £SE3 STJ should he picked up by results ani a used by the classes. The f tbp experiment will be in- , as Mr - F - Tate, who made a repoit on education in New Zealand does not think the service will be of sist C of Val 'v, e '- 7 he Programme will conon* ,°f i a bna£ tal k for senior scholars on topics of the week, followed bv fSre/SS 1 l demonst rations, talks on foreign languages. travel and geography, and possibly addresses 6 by prominent visitors. CATERING FOR THE FARMER A service of educational value parUeular y to farmers, was proposed to but h?vonS U ° W laSt - year by the writer Promise of an appointment which was not made the matter oOt no turther. » The idea was to have f a S POn ? ence course on matters of g. mterest as farm accounts, seasonai cropping, treatment of farmhftvemfb 1 etC V The farmer would hare the course before him and at a woutd bou r the compiler of the course nJ°J hr ° U ! h tbat section before . *** ?TV vl . slble audience, explaining and amplifying his written words, and giving just that personal touch that the correspondence course lacks. By next week the farmer has received the next section, and is ready for the next broadcast and so on, and with proper organisation such a course should be of practical value.

In this respect it is of interest to note that Sydney University has proposed a. scheme in which 5 per cent, of the licence fees are to be divided to research work to establish how best the outbacks settler may be served. REMARKABLY POPULAR “Grid-Bias” in the Wellington “Post” holds a strong brief for the group of circuits known as the Brown-ing-Drake. That these four-valve circuits have taken the home constructor by storm -is evidenced all over the world. This set in its various modifications consists of a stage of neutarlised high-frequency amplification, a detector with regeneration followed by an audio-frequency .amplifier, usually two stages of transformer coupled amplification. The main difference in the various types lie in the methods of neutralisation, in the construction of the primary of the R.F. transformer, and the method of controlling regeneration. A well neutralised four-valve set of this type will be found very sensitive, easy to handle, and capable of results which many six-valve sets would be proud of. As an example of this, a lady in Remuera has a set built to the original specifications, plus a special loose coupled aerial coil and with logged dial settings 2BL Sydney is the regular afternoon entertainment. A loose couplied aerial coil of eight to twelve turns very largely removes the objection of unselectivity which is levelled at this type of set. HINTS FROM READERS THE SUN VALVE COMPETITION Anti-Microphonic Sockets When using dull emitters ordinary sockets often give rise to trouble in microphonic noises. Rubber washers are placed under the sockets. Sponge rubber is especially good. The idea may be applied to any type of valve socket. Using An Old .001 Condenser More Effectively With condenser in use the stations were all crowded in about 15 degrees of the 180 degrees of movement. With a .001 fixed condenser in series with the rotor the same stations are spread over 10S degrees of the dial. . Obviating Leaks in An Aerial Due To Moisture The humble cocoa tin is fitted upside down round the masts above the guv wires, making a water-tight joint round the mast, and inside the eins the mast is quite dry. A similar tin is fitted similarly over the insulated lead in wire. The efficiency of this device is such that since fitting -FC. L’BL and 4QG are regular contributors to this experimenter’s crystal set. ’i his applies to wooden masts only. A Simple Soldering Device A carbon rod from a dry cell is connected to the negative pole of an accumulator and a copper plate to the positive pole. These two electrodes are immersed in a copper sulphate solution to a depth of one inch, and the carbon rod is plated with copper. A copper band is • connected to the carbon rod just above the copper -

I plated end, and a similar band at the other end, and by connecting these twe bands to a six-volt accumulator the carbon rod is heated and the coppered end tinned in the usual way. • The iron is now ready for use, and fitted with a suitable handle carrying flex from the copper bands to the accumulator. With the Radio Trade Three-valve publications which •should be of interest to every dealer are just to hand. .Philips Radio Bulletin, No. 55, describes the new miniwatt A 430, a new H.F. amplifying valve which is claimed to have the lowest internal capacity of any valve hitherto produced, while still giving a very high amplification. The plate lead is led out through the top of the valve and connection can be made to this point or to the ordinary socket by means of a special link. The characteristics are: Filament voltage, 4; filament current, .06: plate voltage, 50-150; saturation current, 10 m.a.; amplification factor, 30. Bulletin No. 56 describes the corresponding six-volt valve with similar characteristics. A Milliard publication entitled the “Triumph of the Wonderful P.M. Filament” is a reprint of a ten-page report from the National Physical Laboratory on a series of tests made at that famous institution on P.M. valves. Such a report is a document of scientific value and should be of use to the dealer, who has a scientific interest in the goods he is selling. Australia has entered the manufacturing field and will have to be considered very seriously. THE SUN was shown a range of Emmco products and with the exception of the audio transformer, which was on the light side, the whole range was sound from both an electrical and a mechanical standpoint. The finish was also very good.

THE winner of this week’s Hints and Tips is Mr. W. Ogilvie, Mount Albert, to whom a valve is being sent. Remember a valve for a useful home idea in radio construction.