QUESTIONS AND ANSWERS

Radio Record, Volume IX, Issue 15, 18 October 1935, Page 49

QUESTIONS AND ANSWERS

a ed "Gon" (Tduranga): If your set, can ~, pick'-up-asfair number ofthe‘ smaller Australian "B" stations’ at, good speaker volume, . thén’ it’.should’ give’ good results When used in coijunction with a, shortwave ‘converter. A-’.separate. . superheterodyne’ designed specially. for .shortwave:work Would give--better results, bat ‘the: improvement’would not .be, warranted by the gréatly -increased' outlay, Adaptors are now definitely out of: date; the best of thém-are'far inferior:{o a’ good: conyerter from the ‘point of view of performance. H:°: (Auckland) :.Iam using:a com- * mercial aerial eliminator, ard. find that, itvgives: results that"are . in. every way superior ‘to !those obtained «from using. an. ordinary: outside aerial. Should this-be.sd ?. By the way, I would.like to

thank . you: for. your recent suggestion as : to. where I would find the fault in my. re ceiver." Ag you’ Suggested, the fault was ‘due ‘to"an "open" electrolytic . condenser. ‘This’ has' been replaced,-and-the set is now functioning well. . Aw: With your type of set .a small aerial’ often. gives more ‘satisfactory results than a:large one, because ‘the selectivity, is greatly improved. Also,, there is. probably’ a, tendency. in, your. set for the rf. stage to.oscillate whe the derial is removed altogether, and when a short aerial.is used, this valve ig much nearer to -oscillation point, and-hence — is. more sensitive than when the first tuned. circuit is. fairly: heavily. damped by attach-. ‘ing a long, aerial, At the same time, _ you ‘have given jo details of the-outside aerial : "you are’ using, and. so it is difficult:to know: whether: the results. you. are getting are aS good as they: should:be, "FEED: BACK" (New: Plymouth) : built’ the’"Viking Junior" in the’: 1984’ "Radio’ Guide" in January last, ' and" "found" it oscillated much -too on ‘all! Bands. * However, : ‘this ‘trouble’: ‘sdon ‘righted’ itself, but ‘has ‘now ‘appeared: again after nine months of. novmal’ working. -I have tried: replaciag the valve: and checking the coil socket, ‘for poor connections. co . As Try connecting: the’ aerial to the top of ‘the grid winding through-a .0001 mfd. ’ fixed : ‘If'this stops ‘the -séet oscillating altogether, then: ‘replace it With a ,00005 mfd. ‘condenser: of the: preset type. ‘If, bow ever,’ the set still oscillates too strongly, then' the strongest possibility is . that the grid Jeak is faulty. . Try. replacing it, with. one ‘of 2: megohms, wNTERESTED": (Pukékohe)':, ‘Lobare recently purchased:. a. .six-valve ali"wave commercial. superhet. Is ‘it. of: suitable. type "for. long-distance reception? ’. A. Yés, quite ‘suitable. , ‘2.9 My: aerial is: ‘about Bott. high: and long. overall, yet I:find that, if I ‘disconnect the-aerial and. attach: the earth lead instead, reception ow the short. waves is just as good. . As: Did-you moye the lead-ini. well away from. -the. earth Jead ‘when you, tried this experiment? , Also, ,your- earth cannot, be a "very good: one. or,at least; the, lead itself must. be fairly long. > Try, connecting a .0001 mfd. «midget . ‘coudenser in: series with. the aerial and adjusting. it on each shortwave station for best: results. "TONE" (‘L'eumarunui) : There is. evi‘dently a pusbpull input transformer in, your ‘receiyer, and if: this is the case Rog

then the crackling" noise ‘you smention- ds ‘niore than. likelyidue to'a defective: primary! winding: The: next ‘eoniponent to sus"peet ist tlre ‘smodthing. ichoke,. if: thete is one in your set. °Try:shorting. the plaze of the detector yalve’ momentarily to chassis. If the ‘primary of the pushpull . transformer is defective, this may cause it-to "epen up" completely, thus providing a. definite indication of the: trouble, "pis" (Dunedin) : "While listening on , _ the shortwave bands, Tam ‘annoyed by, from. ‘passing thotor-cars. Can this be, Stopped? ‘ AL: "Only by erecting an gll- -ware ‘gerial systéni with the flat, top as ‘high ‘above and. ‘as far a& possible. away from. the oad. If you could érect au.aerial of this type; you will find that the gignal- to-noise ratio would be, greatly improved. _ 2. Can I. attach headphones, to my. set, and if so,.in what, way? . Av: You have’ not’ stated what type of valve (or valves) your set uses. in. the output: ‘if you, will: supply, this . detail, we will outlizie the, method | of * .attaching phones, * ‘Note: " With’. reference to. your ‘third ‘query. concerning . your proposed © aerial system, it would bea better . plan if you could erect, two 45ft. masts. at right angles to the road and as far as, possible from it, and sling: the flat top of a noise‘reducing all-wave aerial. between them,