NOTES AND COMMENTS

Radio Record, Volume I, Issue 14, 21 October 1927, Page 10

NOTES AND COMMENTS

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Recently 5Cl,, Adelaide, broadcast to tieteners the sound of the heart-beats of several persons who were invited to be present in the studio. What must gurely be the most unusual broadcast took place on the evening of Thursday, September 22. Recently it caine to 5CI’s notice that a calf had been born n South Australia with its heart situated in its throat. Veterinary surgcons agreed that this was a most remarkable and unusaal freak of nature, and contiderable interest was taken in the animal, By means of the super-sensitive microphone developed by the cngineerng staff, 5CL, broadcast the heart-heat: f the animal. dt an excra long cord 1s cuunecteu tw 4 totidspeaker 12 some instances it will howl, ‘his can generally be stopped by connecting tixed condensers of 002 or .003 mfd across both ends of the loudspeaker cord. A receiving or Wausmitiing valve that Wil not oscillate any more can be made co serve as a rectifier valye as lony as the plate or grid are not shorted to che filament. The socket springs conweeuny co the pvrid and plate of the yalve should be wired together, su that the valve will carry more current. When transformers are sold in couples they are of difterent ratios, ‘he smaller ratio transformer should be inserted m the second stage. The plan of selling transformers in paira is now widely adopted by the manufacture:s, As the transtormers have much to do with the tone of reception, it is inadvisable to buy any but those of the highest grade Iinprovement in audio transformers is conspicuous during the past year = It has been found that if the iron core is large it is not apt to become ‘saturated." ‘Thicker wire in the transformers reduces the danger of burning out under a heavy voltage. There are several makes of sets which require as much as 135 volts on the last valve, with over 100 volts on the previous valve When a 23% volt dry B battery has dropped to 17 or even 18 volts the battery shonld be discarded, The proper time to test the batteries with a voltmeter is when they are connected up to the set aud the valves are aliglt.