Radio Broadcast (May-Oct 1925)

RADIO BROADCAST ADVERTISER 283 This Amazing New 'Type Coil is Revolutionizing Radio Set Building MODERN electrical science has discovered a new principle in radio frequency amplification — a new improved transformer that gives the most amazing results. It is known as the Erla Circloid. Simply clip the coupon below — and let us send you the complete technical story. 4 vital improvements The story of Circloid advantages is a fascinating study — even for those who are not interested in the technical side of radio. As practically everybody knows, in the ordinary radio set, not only the antenna but the radio frequency coils themselves act as pick-up devices of broadcasting signal. This is one of the chief causes of what most radio fans call "broad tuning." With Erla Circloids, independent pick-up of signals by the coils is completely done away with. Selectivity of the receiver is always at maximum. Sharp tuning and less interference are the direct result. Static disturbance has been reduced to the very minimum. For everybody knows that static has no particular wave length. It invades them all. And because the Circloids have no pick-up qualities, only such static as happens to be present on the exact wave length to which the receiver is tuned can Three Great Advantages 1. The absence of an external field eliminates the effect of the coil upon nearby coils or adjacent "wiring circuits. 3. The Circloid has no pickup quality and is rendered immune from outside electrical influence. 3. Its efficiency is higher than any other type of coil and losses are unbe lievably low The New Erla Balloon Circloid Radio Frequency Transformer and Coupler $4.00 come through. Thus here at last is a radio set that offers new delights in summer-time radio. No other receiver can provide such perfect freedom from annoying interference. Another Circloid improvement is greater stability — smoothness of operation and ease of control. The tendency of conventional receivers to squeal and howl uncontrollably is due to excessive feed back between coils and wiring circuits. With Circloids feed back of energy is eliminated between coils and confined solely to the wiring circuits where it is subject to complete control. Thus perfect stability is obtained. Oscillation that is sudden and violent in the average receiver, making it necessary to start tuning all over again, is now controllable. Just the slight turn of one control and it is completely controlled. But the most important of Circloid improvements is its effect upon tone quality. Any radio engineer will tell you that excessive "feed back" is the greatest cause of distortion or blurring. And Circloids, because they have no external field, eliminate stray feed back effects and do away completely with this Pending principal source of tonal distortion. Only with the Circloid principle can supreme musical clarity and fidelity of reproduction be obtained. No other radio set can offer you these exclusive advantages. No other set can offer these supreme achievements. 4 ways to buy the Circloid Erla Circloid Transformers are offered for sale, $4.00 Each — in kits of three, $12.00 — in kits rof three with Erla Condensers, $21.50 — and in Factory-Bilt Kits, $49.50. They may be obtained direct from your nearest dealer. Or write direct for detailed information. £ RUX CIRCLOID cRadio Frequency Transformer *Trade .mark Registered Electrical Research Laboratories, 2505 Cottage Grove Ave., Chicago, 111. Inc. Gentlemen: Please send me detailed information about the new Erla Balloon Circloid Transformer. Name Address. TAr Tested and approved by Radio Broadcast if