Radio mirror (Jan-Oct 1923)

RADIO DI GEST May 12, 1923 Single Circuit Receiver Easily Tuned Local Broadcasters Cut Out by Simple Receiver Most Radio men regard the single circuit receiver as being very inefficient. I have given both the single and the three-circuit hook-up to men who were building WORKSHOP KINKS? EARN A DOLLAR— THERE are many little kinks worked out at home that would aid your fellow Radio worker if he only 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 securing 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 West Madison St., Chicago, HI. their first tube set, and found that the single circuit was best for the beginner, because of the ease in tuning. The signal strength of a single circuit set is greater than a three-circuit set. Now then we will come to the part that gives us the trouble. After the Radiophan has the single circuit set in operation for some time he finds that he is bothered with local interference, or in other words when a local broadcasting station is going he cannot hear the distant stations. The usual way to direct him is to buy two variometers and change his set to a three'-eircuit tuner. This circuit is more or less complicated to operate and does not give the same results at first that the single circuit set did, and our friend thinks he has been fooled. I have had this very thing put up to me ever since broadcasting began and I have found a solution to this problem. With the parts as given in the material list a single circuit set can be built that will be found very selective. MATERIAL LIST 1 Moulded variometer 1 23-Plate vernier condenser 1 3-Plate variable condenser 1 Rheostat 1 Tube socket 1 Variable grid condenser 8 Binding posts 1 6xl2x ■''., Inch formica panel By referring to the hook-up you will note that the variometer has been disconnected so that the stator windings can be used independent of the rotary windings. The stationary winding forms the main inductance and the rotary winding forms the tickler or feed-back inductance. The ordinary single circuit hook-up is used except that the 3-plate condenser is connected across the main inductance. The aerial binding post should be connected to the stationary plates of the variable condenser to reduce the capacity effect. If this is done and the variometer is a good moulded one it will not be necessary to shield the panel. % |,LtpA~ BATTERY Another important item is the variable grid leak. Be sure and use a good one. In operating this set tune in some distant station and adjust the B battery and the grid leak until the best results are obtained. After this is done it is only necessary to tune the variable condensers and the variometer, and the grid leak will not need adjustment in tuning, if the music you are listening to does not sound just right tune in another station and see if they are not better, sometimes the trouble is in the broadcasting station and you will only get your set out of adjustment by trying to clear them up. If these directions are followed out carefully you will find this a wonderful set, so be sure and read the article carefully before building the set. — John H. Boos, Jr., St. Louis, Mo. Simple Long Wave Set In the illustration is shown how to make connections in an aerial system for re ceiving long wave signals. With this hook-up I can plainly hear NSS. The diagram is self-explanatory. — Fritz Franke, Chicago, 111. The Idle Battery Storage batteries which are to stand idle for a month or two should be fully charged before being put away. If the battery is permitted to stand for any length of time in a discharged condition, the plates will become white, an indication that sulphate is forming, which is very harmful to the cells. PHANTOM-CIRCUIT Build Your Own. This marvel of mystery, using do loop, no aerial and do ground, brings in music instead of Interference. We have heard stations 950 miles distant on one tube. By using WD-11 tube set can be entirely self contained. Very easy to build from our Instructions, use your own spare parts, nothing complicated like radio frequency or super regenerative. Only one tuning control. Complete instructions, with hookup and photo of circuit mailed to you for 60 cents. Stamps accepted. VESCO RADIO SHOP. Box 0-704, Vacaville, Calif. CDTOCDIL CO. PROVIDENCE Built First to Last Care of Storage Battery The following pointers will be helpful in keeping your A battery in proper condition: Do not allow the battery to become completely discharged. Always maintain the level of the electrolite (acid and water) above the tops of the plates, usually % inch. Keep the battery well charged at all times, as it is difficult to revive a dead battery which has been standing idle for a long time. Do not allow the electrolite to bubble over on to the tops of the cells. If this happens, reduce the charging rate. Keep the top clean to avoid leakage loss. Determine the gravity range of your particular battery and keep it within proper limits by frequent tests with a hydrometer. Rubber Tube in Shaft Shields Variometer In your March 31st issue under the Question and Answer department you informed Number (2150) HCH, Charleston. W. "Va., that there was no practical means of reducing body capacity except by shielding the panel of the receiving set. The accompanying sketch shows the methods employed to eliminate body capacity. The condenser and coupler are set back 0ESIR.ED LENGTH from the panel and the shafts are made short with a piece of hard rubber tubing connecting them. — Judson C Sullivan, Akron, Ohio. WD 11 Hook-Up positively free of body capacity also giving selectivity, sensitivity and record distance, postpaid for 25 cents, or complete set of parts for $13.50. C. W. KAUTZ Box No. 362 Lancaster, Pa. BETTER LOUD SPEAKERS $9.85 3 ^BJI^C T-T-.T ?:?r TRUE CABINET TYPE, like the finest >0»tWfe modern phonographs, with all their beauty 4fr>* bSS anc1 perfect tone. Makes your two-step set a real ENTERO^JH TAINER for family and friends. SPIROLA DUPLEX uses any W| W headset. SPIROLA SIMPLEX uses Baldwin or other unit. ^^^^^ Either type, black with nickeled fittings, $3.85; mahogany finish with bronzed throat, $4.85. T ,T w-!tC5 or postpaid (C. O. D. if preferred). Absolutely guaranteed. T,. H. DONNEIJ, MFG. COMPANY. Dept. P. Box 70. ANN ARBOR. MICH. WILLARD WILLARD RADIO COMPANY Dept. R. D., 291 Broadway, New York City "The Best for Less" FLEWELLING CIRCUIT EVERY PART COMPLETE 2 honeycomb coils. 1 2-coil mounting, 2 coil plugs, 3 .006 condensers, 1 variable grid leak, 1 grid leak, 1 23-plate .0005 MFD. variable condenser. 1 Vernier rheostat, 1 tube socket, 8 binding posts. 20 feet bus bar wire, 1 high-grade panel ALREADY DRILLED AS PER DIAGRAM, 1 3" dial and the Radio Digest Booklet on Operation and Construction of Circuit e Dinning posts, $11.00 Two-Stage Radlr> Fremienry Amplifier— Parts complete in every detail for this Circuit— $11.00. 3 Plate 13 Plate 23 Plate 43 Plate CONDENSERS Variable; value, $3.50.... , $1.05 ... 1.35 13 Plate 23 Plate 43 Plate VERNIER: value, $5.50... VERNIER; value, $6 00 VERNIER; value, $6.50... ... 3.75 ... 4.25 VARIOCOUPLER — Celeron Condensite and Iatz Wire Wound Secondary; Value $4.50. Special $2.95 AUDIO FREQUENCY TRANSFORMER — Designed for use with W. D. 11 Tubes, list, $4.50; price $2.75 Honeycomb Coils, 50 turns mounted. $0.95 Honeycomb Coils, 75 turns mounted. 1,00 Double Coil Mountings 2.45 Triple Coil Mountings 3.35 Reinartz Coils and Mounting 1.75 BALL BEARING INDUCTANCE SWITCH— value 75c, special $0.30 V. T. SOCKETS— Nickeled, brass sleeve, composition base value, $1.00; special at.. .50 EXTRA SPECIAL— Telephone 3000 Ohms Headsets: $9.00 value; reduced to $3.50 ALUMINUM LOUD SPEAKING HORN— Nickel plated, highly polished; $8.00 list $3.75 A BEAUTIFUL "SALRITE" PENCSL FREE With every order of $12.50 or more. Made of beautiful Mahogantte Rubber, about five Inches long. Equipped with vest pocket clip, 10 extra leads and eraser. Will write like a charm and last a lifetime. Only a limited supply available — so rush your order now. BEST QUALITY 1ACKS, Single Circuit; value, 65c; special at 30 Double Circuit; value. 90c; special at 45 MULTIPLE POINT INDUCTANCE SWITCH with Knob and Dial (15 switch Points) 1.75 LIGHTNING ARRESTERS approved by underwriters $0.90 THREE-INCH DIALS — Unbreakable — heat resisting composition— high finish: special. .$0.30 TWO-INCH DIALS — Same design — for rheostats and potentiometer; speoial at $0.25 FILAMENT RHEOSTAT— Condensite base; value. $1.10; special at .70 FILAMENT RHEOSTAT value. $1.50; special at. with 2'/a" dial; TELEPHONE PLUGS ■ 60 FRESHMAN VARIABLE RESISTANCE LEAK and MICON CONDENSER Combined .75 REINARTZ CIRCUIT EVERY PART COMPLETE ,,,5? ,^ST?ound cml 1 tube socket, 1 rheostat, 1 23-plate .0005 MFD. variable condenser. 1-13-plate .00025 MFD. variable condenser, 3 Inductance switches. 16 switch points and Duts, i switch stops and nuts, 8 binding posts. 2 3" dials, 1 variable grid leak. 1 .002 MFD. phone condenser, 23 feet bus bar wire, 1 high-grade panel ALREADY DRILLED AS PER DIAGRAM and complete Instructions $10.00 Two-Stare Radio Frenueney Amplifier — Parts complete In every detail for this Circuit — $11.00. Every article advertised above is guaranteed by the manufacturer and by us — Mail orders filled immediately — transportation PREPAID on all orders of $5.00 or over east of the Mississippi River. All others include postage.