Radio Digest (Oct 1923-July 1924)

March 29, 192 % RADIO DIGEST — Illustrated 27, Single Circuit Using Dry Cell Tubes Portable Set Carried On an Automobile Trip THE little UV-199 dry cell tube, since its introduction a few months ago, has come into quite general use, but has not always given the results that were expected of it. This is due in most 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 cases to the way in which the tube is used, rather than to any defect In the tube itself. The writer has had considerable experience with these tubes and has found them satisfactory both as a detector and amplifier. They are not at all critical as to either plate or filament voltage, though, of course, they should be operated at the proper filament voltage to insure satisfactory life. In spite of the fact that the filament is small, the tubes are very rugged and will stand as much rough treatment as any tube on the market. During the past summer the writer took a three tube portable set on a 350-mile automobile trip through the Adirondacks, on several occasions traveling roads that were almost impassable. Though the UV-199 tubes were in their sockets all the time and the set rested on the floor in the back of the car, they came through safely and furnished nightly entertainment during the trip. Dealers! A BRAND NEW CATALOG! Just out — crammed full of everything you want in high quality radio supplies— the most complete display in the Middle West — the biggest stocks, best discounts, quickest shipments. This book will be sent ONLY to dealers. Ask for A1002. No others need apply. WkKtM&M?LAUGHUN««c 22S E. I lli nois St., Chicago eVEREADy Radio Batteries -they last tonget Conspicuous for vitality and endurance — the right batteries by test and proof for every radio use. NATIONAL CARBON CO., Inc, Headquarters for Radio Battery Information New York San Francisco Canadian National Carbon Co., Limited Factory and Offices: Toronto, Ontario TWO STEPS OF A. F. IN HOOK-UP The secret of the successful operation of these tubes is to follow closely the instructions on the printed slip packed with each tube. As stated in the instructions, when the tube is used as a detector, the grid return should be to the positive terminal. In all cases the rheostat should be in the negative lead. This, of course, is good practice with any tube. The plate voltage is not at all critical, and the tubes will detect well with from 20 to 45 volts. The writer has seen two of these tubes which operated very well as a detector with 90 volts on the plate, but this is exceptional. As a rule, 45 volts is very satisfactory. When used as an amplifier the grid return should be to the negative side of the A battery, and not to the filament. To get the best results from your amplifiers, use 90 volts on the plate, and insert a grid bias of 4% or 6 volts in the grid return. This will give amplification that will compare favorably with that obtained from storage battery tubes. Another point to remember is that these tubes are decidedly microphonic, and should be mounted on pads of felt or sponge rubber. It is also well to make connections to the socket with very flex Wavelength in meters ISO 300 3SO *K) 4SO 500 SJO> The Dubilier Duratran The radio frequency transformer that amplifies uniformly over all broadcasting wave lengths. Price $4.00 at good dealers. Dubilier Condenser and Radio Corp. 44-50 West Fourth Street, New Vork Guaranteed Head-Sets RED-HEADS" are guaranteed radio phones. You run no risk when you buy them. Money back if, after 7 days' trial, you're not satisfied that they're the best receivers on the market at the price. Why not act right now and get a pair? It'll mean getting the maximum from broadcasting from the day you put them into use. NOW READY The i.ew 1924 Model P Sfi «%0 Per ralr *0.3V» Complete I The new "Red-Head" Jr. •cc; on p«p«'r •P3,uu Complete "Red-Heads" sent prepaid on receipt of price if you are unable to get them at your dealer's. THE NEWMAN-STERN COMPANY Dept. R. D., Newman-Stern Bldg., Cleveland ible wire, as stiff bus wire connections will make cushioning useless. The hook-up given is of the single-circuit feedback variety and shows the proper connection of grid returns and bias battery. The single rheostat for all three tubes is entirely satisfactory with these tubes, and for three tubes should have a resistance of 10 to 15 ohms. The two steps of amplification shown will give good volume on a loudspeaker for home use. — Lee M. Klinefelter, Norfolk, Va. Keep Direction Sheets Do not throw away the direction sheets or booklet that came with your set and with the tubes. Read all such material carefully now and then. If you have lost the direction sheets, write to the dealer or manufacturer for another. These sheets will answer most of the questions which have been puzzling you and preventing you from getting the best out of your set. Don't insert vacuum tubes in sockets unless absolutely certain rheostats are turned off or at the proper setting for normal position. WHERE I GO & BY RADIO I ! >— 31&-71K tt.l Used in 41 States & 7 Provinces, 2 Foreign Countries Within 4 Months After First Issued "WHERE I GO BY RADIO" Unique System. E'ery Line Com IDEAL PIete Be«>rd When. Where. How and What You "Tuned in." also RADIO Accurate List Radio Stations. Other useful features. Popular RFCORD Edition, space 800 Records. 2 for V $1.00. BOOK Holiday Edition, space 700 Rec ords, only $ 1 .00. Get at any Newsstand, Bookstore or Dealers, or send $1.00 direct Now to Radio Book Dept., Progress Press Drawer R Union, South Carolina, U. S. A. s\ WE REPAIR THH FOLLOWING RADIO TUBES Dealers and Agents write for Special Discount Mail Orders Solicited and Promptly Attended to WD-11, WD12, Our Specialties WD-11 $3.00 WD-12 3.00 UV-200 Z.7S UV-201 3.00 C-308 2.75 C-301 S.00 DV-6 3.00 DV-1 3.00 DV-Z 3.00 DV-6A $3.00 UV-199 3.00 C-299 J.00 UV-201 A 3.00 C-S01A 3.00 Marconi 3.00 Moorhead 3.00 C V. Plain Det.. 2.75 < V. Plain Amp.. 3.00 H. & H. RADIO COMPANY P. 0. Box Z2-A Clinton Hill Station NEWARK. N. J. Vernier Tube Control With Horseshoe Magnet A novel vernier which may be added to any set is shown in the illustration. The horseshoe mar the electrons in side the detector tube, and with proper adjustment, it Is not necessary to burn the HORSE SHOE n aon t FRONT VIEW SIDE VIEW detector tube filament so high. Consequently, this is a form of vernier which not only gives tine control, but serves another purpose as well. — J. B. Owen, Blair, Okla. It is more difficult to tune out local stations when a long antenna is used than when the aerial is fairly short. There la, however, a decrease in volume on the short aerial. RADIO "B" BATTERIES At Factory Prices Greatest Radio "B" battery on market. Full number voltage tapis; QUALITY GUARANTEED: LOWEST PRICES; brings in concerts LOUDER AND STRONGER; will work on any tube or loud speaker. Order by number TODAY with cueck, money order or pay postman C. O. D. No. 322B— 22'/j volt, variable, *i CO reoularly $2.25 $I.D£ No. 322A— 22"; volt, variable. (1 OS regularly $3.00 $1.03 No. 345A — 45 volt, 8 taps, «»? OCT reoularly $5.50 yo»£.0 AYRES BATTERY CORPORATION, Cincinnati, Ohio DEALERS* PROMPT SHIPMENTS LIBERAL DISCOUNTS Erla Selectoformer As Usual We Are First With the Latest Send in your name so we can send you our complete catalog on all the standard lines. Tlfrtfi.!! J>WeJ*i/n.tf (TUxHE !I'hm:bcW 123 W. Madison Jt.Chica