Radio Digest (Oct 1923-July 1924)

_, February 2, 1924 RADIO DIGES T— Illustrated Compact Set Using Bean Ordinary Spider Web Winding on the Form THE writer recently completed a miniature set of rather novel construction. This set consists of a standard regenerative circuit employing as inductances triple coils of the spider web PANEL LAYOUT FOR INSTRUMENTS WORKSHOP KINKS? EARN A DOLLAR— THERE are ' many little kinks worked out at home that would aid your fellow Radio worker If only he knew about them. There are new hook-ups, new ways of making parts and various unique ways of operating sets that are discovered every day. Radio Digest is very much interested in obtaining such material. Send them in with full details, including stamped envelope, so rejected copy may be returned. The work must be entirely original, not copied. RADIO KINKS DEPARTMENT, Radio Digest, 123 W. Madison St., Chicago variety, but of a shape similar to the kidney bean. These coils are concentrically mounted on two shafts, one tubular, the other extending through this tube, in such manner as to be operated from the front of the panel. The two operating knobs are shewn in the picture. The set is inclosed in a cabinet, 7 inches long, 5 inches high and 3 inches deep, inside measurements. Description of the Set The picture of the inside of the set shows the manner of mounting the various parts and construction of the inductances. Of the three coils used in the circuit the secondary, which is permanently mounted to the panel, has 55 turns of number 28 sec. wire; the primary has 45 turns, while the tickler coil has 30 turns of the same size wire. The primary and tickler coils can be rotated past the secondary through 180° and are spaced % inch apart. In practice it is seldom found necessary to move the coils from a position exactly opposite one another, all tuning being done by the secondary and tickler condensers. When, however, interference is encountered a slight shift of either the primary or tickler coil with relation to the secondary will suffice to clear variable condenser and a 23-plate air condenser is used to tune the tickler circuit. No condenser is used in the primary. The coil forms are cut from 3Vinch gray fiber, properly shaped, and each has 4 3 slots, % inch deep, to carry the windings. The outer coil, the tickler, is fitted with a 1" BEZEL. ANTENNAPOST VAR.COND, DOUBLfKNOB ASSEMBLY FOR SHIFTING COILO A A \_J © (g) RHEOSTAT © © 23PI.CON0. up reception. This method of tuning, that is, to shift the inductances concentrically rather than laterally, as in the ordinary spider web coils, has been found very satisfactory. The illustration shows a Myers tube in use in an adapter for a standard socket. The secondary is shunted by a Brockway "Just What I've Been Looking For" said a prominent manufacturer of fine radio sets after he had tried out the C R L Non-inductive Potentiometer. "The C R L Potentiometer is absolutely non-inductive," he continued, "and does not damp down the oscillations in the circuits. "The set, therefore, can be operated at its maximum efficiency at all times. I also like the C R L Potentiometer because it is neat, compact, and because there is nothing about it that can come loose or wear out." A perfectly non-microphonic contact is made with the resistor by the patented C R L method. This gives noiseless adjustment through an infinite number of steps. No. 110 (400 Ohms) $1.75 No. Ill (2000 Ohms) . . . 2.00 By Parcel Post, 10c extra. Central Radio Laboratories 312 16th Street, Milwaukee, Wis. Nan— Induct iv« onTENTIOMETER small brass counterweight; this with the natural friction of the close-fitting shaft running through its accompanying tube suffices to make the coil "stay put." The brass tube-shaft carrying the primary coil is frictioned by a small spring. The (Continued on page 30) DEALERSl PROMPT SHIPMENTS LIBERAL DISCOUNTS "ERJLA" New Type Reflex Transformers All Erla reflex parts in stock including Hilco Variocouplers and Rathbun Condensers. Dealers send for Catalog and discounts »H»3:flti*» 123 W, M ad iron Jt. Chicago S\ WE REPAIR THE FOLLOWING RADIO TUBES Dealers and Agents write tar Special Discount Mail Orders Solicited and Promptly Attended to WD:1^ OUR SPECIALTIES { 5T REMITTERS UV-199 $3.50 UV-200 2.7S UV-201 3.00 UV-Z01A 3.S0 WD-11 3.50 DV-6 3.00 UV-202 4.00 UV-299 3.50 C-299 $3.50 C-300 2.75 C-301 3.00 C-301A 3.50 WD-12 3.S0 DV-6A 3.50 C-302 4.00 H. & H. RADIO COMPANY P. 0. Box 22-A Clinton Hill Station NEWARK. N. J. "TOE ACCENT IS ON SERVICE* 14-16 Vesey St. NEW YORK VARIOCOUPLERS $3.50 Workrite 180° Silk Wound $2.95 3.50 Fisher. Large," 90° 2.75 2.75 Fisher, 180° 2.25 VARIOMETERS $3.50 Workrite $2.95 5.00 Pathe Moulded 2.25 3.50 Fisher. Large 2.85 CONDENSERS $2.00 B. C. 11 plate $1.05 2.35 R. C. 23 plate 1.35 2.75 R. C. 43 plate 1.65 VERNIER CONDENSERS $4.00 R. C. 23 plate $2.25 5.00 R. C. 43 plate 2.95 PHONES $18.00 DR. SEIBT IMPORTED "SUPERdlC' Qrt HEADSET" ..._ $0.»U $12.00 N. & K., Imported $5.90 We specialize in the FAMOUS AMBASSADOR LONG DISTANCE CIRCUIT. Write for list of parts for this set. Either single or three tube set. Price of parts for single tube set $15.60 Price of parts tor THREE TUBE SET 28.90 Mail orders promptly attended to. All orders amounting to $5.00 or more will be shipped prepaid. Will ship C. 0. D. unless remittance accompanies order. The above items are Just a few of our numerous attractive priced articles, which are contained In our BULLETIN OF RADIO PARTS. Gladly sent to you upon request. ed Coils Small Soldering Iron Made of Copper Wire A short time ago I chanced to be miles away from a soldering iron and greatly in need of one. I produced a makeshift from a piece of ijumber 14 electric light wire which was rubber covered. The piece used was 12 inches long. Four inches of the insulation was removed from one end and \\'2 inches taken off from the other. and a loop was formed of the covered part to make a handle. On the long, bare end I wound a bunch of number 22 copper Wire to hold the heat. This, heated over a gas flame, was found to be very handy and useful for soldering the wire to taps on the variocoupler. It will reach into places where a common soldering iron will not enter. — George H. Humphrey, Providence, R. I. ON ONE TUBE Broadcasting from Atlantic Coast, Mexico. Hawaii. Canada and Cuba heard In California by users of CROSS COUNTRY CIRCUIT. Range due to simplicity of set and only one tuning control. Easily and cheaply built by any novice. Dry cell tubes may be used. All instructions, blueprint panel layout, assembly photo, etc. Postpaid, 25c. Stamps accepted. VESCO RADIO SHOP Box D-II7 OAKLAND, CALIF. No more antenna— just the Ducon in a lamp-socket. Amazing results with the DUCON WITH just the Dubilier Ducon in a lamp-socket the threetube neutrodyne set of G. W. Weston of the Kansas City Electric Club picks up Havana, and other distant stations. "I am amazed at my results," says Mr. Weston. "I see no reason at all for an outside aerial." 400,000 satisfied users. Price $1.50. At good dealers. Money back if unsatisfactory after five days' trial. Dubilier Condenser and Radio Corp. 48-50 West Fourth Street, New York Radio Frequency Set for Only $3© Send $30 today and receive prepaid this fine & non-regenerative Radio Frequency Set. Results guaranteed equal to sets costing three or lour Times as much. Four rube assembly — detector, 1 radio, 2 audio Irequency Only one simple adjustment lor wide range ol wave lengths. Perlcci modulation No howling or squeaking Large, complete production in out own lacier) makes this wonderkul value possible Make vj iiiaiMO nil? ..uimtllUI VdlUC JJvK»U»lC JVldJvt? «J 8 draii or money order payable to ClEVELAiND S § APPARATUS COMPANY. GRAFTON. OHIO ^ (rue NIGHTINGALE 1