With the Experimenter

Radio Record, Volume III, Issue 41, 24 April 1930, Unnumbered Page

With the Experimenter

Some Useful Points

TF you are doubtful about your ability to obtain a well-finished wooden cabinet, do not forget that rexine and léatherette have possibilities as covering materials. * Bs * F your aerial runs close to your neighbour’s do not share an earth with him, as this often gives rise to mutual interference. x *-: * DD lengths of wire which would , otherwise be thrown away can often be wound upon empty cotton reéls, and can then be thrown into the tool box instead of into the dustbin. * = F you ask a carrier strap for your accumulator on no account allow the acid té come into contact with this, for it may break when you are earrying the battery. over the carpet one day, with disastrous results, * » "« OWING to the very high frequencies used in modern ‘short-wave work the term "mega-cycle," Which meas one million cycles, is coming into fayour amongst:experimenters, % % * — Ete work» who like doing delicate work will find that improved results are sometimes obtainble with a horn type loudspeaker if the two magnet cdils under the diaphragm are connected in parallel, instead of in series. % Dd % HEN fitting a potentionméter to improve sensitivity or reaction control, remember that its action must be smooth and reliable. or it will cause far more trouble than it. is worth.

ERY often a short-wave set’ works bettér without the earth connection. * * * O not expect a ‘super-power valve to increase volume, because its function is not to provide this, but to handle it without distortion. * * 2 LAT spots or dead spots in shortware tuning are due to aerial tuning effects and can be shifted by connecting a variable condeiisér in the aerial lead, adjusting this ‘when neces sary. = * % HN wiring up a screen-grid valve remember that the P. termitial of the valye holder will not be the output terminal, but will supply the necessary priming voltage to thé screen of the valve, * = 2 F your set is to use only one antimicrophouic, and the rest rigid valve holders, remember that it is usually the detector which gives rise to noises, so the anti-microphonic holder should be used for jit. = x 2 N ordinary neutralising condenser makes an excellent means of loose coupling the aerial for short-wave work if connected in series. (Readjust the condenser if "blind-spots" are troublesome. ) : " A SHOCK to the telephones, such as is caused by dropping them upon the floor, is liable to damage the permanent magnets and to render tlie insenisitive.