Notes and Hints

Sun (Auckland), Volume II, Issue 315, 28 March 1928, Page 16

Notes and Hints

THE CRYSTAL SET cf a peverii sparser everal pair* ot_ z=^j —vix-d cardboard us c -.te g.od. " A • - 1 - proof fll are a* groarca as one coil! expect of er. article eoialneted by so roany to be standard—-freak circuits too often. ever design Is- employed- It —-II be next to neellf small Inefftooeno-oe* w.tloh in tr.e crystal outfit mean ilte deference b-etweert stseeess and fa.lt re. stal set rn tjrt be a* efficient a* poss.-o.e. HAlf lie S«2 wb.ob di*toted o-KV.mrs are not gp.ot; o to Z-Ol » •' aerials and probably poorer earms. The lead-in and the earth -re .booo Id be as shorn as poerible, every joist mrnsr be solderedDANGER OF WRONG WIRING Probai>’.y tor ele r va. v* -ri’ r .C- h *. r/, arl 'i:' ; it r , a. nanrai death, ten others eorre to a violent er-'i tftro-gh care.eeer.eaa or the o*-o-er* part- Again, o£ these, a fair prope.rtior. are Irarnt ort -r the preLir.-t.h-ary conr.er-hhg up oi the get, due to grror.g to-tring or mistakes m tr.e conneotions to the tatterfei. And _ -while, throughout the tide of the it t= - be expecheti that accMeau wuS happeri ' they can be avoided at least m the iaitiai try-out. In rrAvir.g the connections to a e'.

for the first time, the best piar. i- to - hook up the “A” battery first to see .f each valve lights from its correct cor. nections, tryir. g each one separately. A pair of 'phones, or a voltmeter tar. be used, if the valves are dull emitters and show no light, to ascertain if the current Is reaching the right contacts , only. Then, making doubly sure, connect the A” battery to the "B" battery terminals. If the valves still light, then obviously something is -wrong, which means that they will be blown If the ‘B" battery is connected. -<o harm, however, has been occasioned in finding this oat- If everything else seems to be in order, there is only a very remote chance that any accidet. will happen when the set is finally connected up. RADIO COMPETITIONS From Station 3LO, Melbourne, the station cf splendid programmes and equally splendid dividends to its 1 shareholders. The Sun has received a 1 typed circular giving particulars of 3LO's latest competition. The contents of the circular are given below: 3LO MELBOURNE FREE TRIP TO WEST AUSTRALIA I “When Australia was spanned from | east to west by the great trans-con- ' tinental railway and Fremantle be- ; came the western gateway of the coni t.inent, the lifelong dream of the late Lord Forrest —one of our noblest statesmen —was realised, i “Until then "The Land of the Golden West,’ in its immensity and isolation, I was a veritable continent unto itself, accessible from the east by a long ; ocean journey of about a week. ! “Xow, however, access to and from ; Perth is possible by railway in half i that time, and the Trans-Australian . Express is acknowledged by world travellers to be among the best in existence, ’ not only for up-to-date equipment and comfort, but also for i ' attention and service. ; I “Following upon the huge success of . ■ their free trip to Tasmania, the direc- : i tors of 3LO Melbourne have arranged to give a similar free Easter trip to V."e--t Australia for two persons commencing on March 31 and ending on : April IS—everything free of expense i to the lucky winner. "All that is necessary for applicants - to do is to send name and address, together with the number of the licence I of the wireless receiver by which tney j usually listen-in to 3LO Melbourne, Melbourne Place, 120 a Russell street, , ; Melbourne. One supposes the chance o. w inmn & such a trip might induce a few people to take up radio, but tha. cannot possibly be the main object of these competitions. The sp*ce of the ; Australian programmes is novelty ana : some novelty stunt is usually devel- ! round these competitions and so much indirect advertising of the etation is gained and both the Listeners and the station benefit. HOW FADING MAY BE PLOTTED The only instrument needed Is a good milliameter reading 1.5 or 2 m.a. j maximum. The meter is connected into the detector xB lead. When a signal is tuned in the reading will be less than wherr no signal is being received. ; For example, if no signal is being rei ceived and the m.a. reads 1.2 and reads i 1 when a signal is tuned in, then the .2 ; decrease depends on the strength of , the tuned In signal. If this value of I decrease in meter reading varies with I time it shows fading and the value of . the decrease should be plotted against j the time in minutes, and a graph of the fading can be obtained.