Radio broadcast .. (1922-30)

Reflexing Your Single Circuit Receiver Various Circuits and What They Mean PART VI By ZEH BOUCK There are only a few of our readers to whom RADIO BROADCAST has preached, in vain, the evils of regenerative single circuit tuners. But many owners of single circuit apparatus protest against junking equipment in which they have invested, perhaps, hundreds of dollars. —There is a certain justness in their point of view. However, there is no necessity for relegating the single circuit regenerator to the ash-can. They can be made over, at a very small expense, and with an increase in efficiency into the "Knock-out" reflex circuit that has taken our readers by storm. Mr. Bouck tells how to do it. — THE EDITOR. M UCH has been said and written condemning the single circuit regenerative receiver. So vehement has been the reaction against radiating (not eradiating) receivers, which, like the spark transmitter, has lived its day that was genuinely useful, that there are a very few, even among the manufacturers, who fail to appreciate and proclaim the iniquity of such oscillators. But regardless of the universal appreciation of the several faults of single circuit tuners and the sincere desire to remedy them, the propaganda against them has been mostly destructive, except for advocating a complete change in receiving equipment. The manufacturers have quite profitably backed this advice by placing on the market, at the psychological moment, non-radiating equipment. But there are many of us who, urged by these same manufacturers only a few months back, invested our entire radio budget in the receivers that they now condemn, and who must necessarily hesitate before making the change that means so much to general and individual radio improvement. While several substitutes have been suggested for the offending circuits — straight radio-frequency amplification, the neutro What You Need to Build the "Reflexit" IF YOUR set is a single bulb receiver of the type described, the following additional items are necessary to avoid the blot of ostracism: dyne, the super-regenerative and reflex sets — from the standpoint of economy, simplicity, and the loudness of signals, the three amiable characteristics of the defunct criminal, the one-tube reflex is the only substitute. It is more than a substitute — it is an improvement. DO NOT THROW AWAY YOUR SINGLE CIRCUIT RECEIVER TO ACQUIRE the advantages of the reflex receiver, it is neither necessary nor desirable to discard your present single circuit set. By altering a few connections within the receiver and building up a small external panel, all quite within the ability of our more timid experimenters, the most powerful single circuit oscillator can be converted into a reflex set that is a revelation in quality and intensity of signals. Fig. i is a photograph of one of the most prevalent types of single circuit regenerators transformed into the reflex. Figs. 2 and 3 are close-ups of the extra panel equipment that effects the conversion. For want of a better term, and because the same auxiliary arrangement may be applied to any single circuit receiver regardless of superficial circuit variations, the writer has named this little secondary panel the "reflexit." One crystal detector (preferably fixed) $1.25 sth pound No. 22 magnet wire 35 One length 3 inch cardboard tubing 15 One .00025 rnfd. variable condenser (Ca). . 3.00 One audio amplifying transformer (T3). . . . 4.00 One panel, 5" x 6" .50 Knob and dial 50 Incidentals 25 Total $10.00