Radio Digest (Oct 1923-July 1924)

RADIO DIGEST — Illustrated March 15, 192. HINTS FOR LISTENER IN Correct Potential Th ">" t0 ■ tube deWith -ults visable to use .Us. high . hard lube will ( 0 45 volts wry. method of regulating ntial by means of shunted across the nla Ivis&ble to use a high t potentiometer for this cure an unlimited tie condi when tuning in distant stations, be . rnier voltage regulation of the detector tube plate is thus obtained. the set to its most sensitive state. For best operation of the detector tube, it is usually pre: to connect the grid return to the positive side of the flint, using as low a plate potential as ■-• for best results. When vacuum tube as an amplifier, it is ■ that the filament rheostat be connected in the negative lead and that the grid return lead be connected to the side of the battery and not to time side of the filament. This places a negative bias on the grid. If more than 40 volts are used on the plate, the negative grid bias voltage thus pro not suificient and an additional Sing battery, or C battery, should be used. When a C battery is used it is connected in the common grid return lead of all the tubes, as indicated in the diagiven in Figure 5. Connect the grid rn terminals on the amplifying transformers by a common wire, connected to the negative terminal of the C battery. The positive terminal of the C battery is connected to the negative terminal of the filament or A battery. The chief advantage of the C battery lies in the fact that it causes a material reduction in plate current and thereby prolongs the life of the B battery. Voltage of C Battery The negative potential which should be applied to the grid of an amplifying tube depends in some degree upon the signal strength and on the B battery voltage used. A 4 Vz -volt C battery will be sufficient with most tubes when plate battery voltage of not over 80 or 90 volts are employed. For plate potentials up to 120 volts from 6 to 9 volts of C or grid biasing battery will produce best results. When employing audio frequency am (Continued on page 24) FERBEND An Easy Way to Cut Out Interference Add a Ferbend Wave Trap to Your Set It isn't hard to receive nowadays on most any good set from stations all over a country as big as the United States— if the nearby station doesn't interfere. Even then, if your set is extremely selective, and if you have the right antenna, and if you are an expert at tuning — and if you have good luck — you can perhaps tune out the offening transmitter. Do not be misled by Imitations. The FERBEND WAVE TRAP is the first Inductive as well as the Original Wave Trap. It is not assembled haphazardly from standard parts, but is made up of special parts designed and manufactured by us for the sole purpose for wkicb they are used The FEBBEXD WAVE TRAP is mounted on formica panel In mahogany finished cabinet 6i5i6 at $8.50 or unmounted at $6.00. °STOP3 INTERFERENCE THE FERBEND WAVE TRAP MAKES YOUR SET SELECTIVE READ THE EVIDENCE! It happened that Wm. L. Mann, of 767 N. Fortieth St., in Philadelphia, didn't have all these things— so he just bought a FERBEND WAVE TRAP, and now he says he has no trouble tuning out any of the four big Philadelphia stations. The same thing can be done (probably is being done) in your town. Try it! ANY NIGHT is "SILENT NIGHT" with a FERBEND! Wonderful Selectivity for You with a FERBEND WAVE TRAP on your set. You will be surprised at the ease and sureness with which you can tune out that troublesome interfering local station that is always breaking in every time you get some favorite station. The FERBEND WAVE TRAP is guaranteed to tune out any interfering local station. Why wait? Order now. Send No Money Just your name and address, and pay postman $6.00 (plus postage) for the unmounted, or $8.50 (plus postage) for the mounted Wave Trap. If you prefer, send cash in full with order and we will ship postage prepaid. You take no risk, so order today. "The Orijtinal Wave niter" Ferbend Electric Company ANY NIGHT U "SILENT NIGHT" with a FERBEND! Dept. 3 IS East South Water St., Chicago PEERLESS RADIO, 349 Fulton St. BROOKLYN, N. Y. Parcel Post prepaid on all orders above $5.00. Express Money Order, Certified Check, Bank Draft accepted; also C. O. D. Guarantee with all merchandise. LOUD SPEAKERS Maanavo* (new type) $27.25 Music Master 25.45 Path* (new type) 16.50 Dictogrand 15.25 Stromberg Carlson 17.75 Mercury with Baldwin Unit... 9.95 Natl. Baldwin Type C Unit.. 4.85 Manhattan Electric 22.50 Brand** Table Talker 9.95 Accuitieola Phonograph Unit 9.45 VARIABLE CONDENSERS II PL Admiral or Signal $1.35 17 PL Admiral or Signal 1.60 23 PI. Admiral or Signal 1.65 43 PI. Admiral or Signal 1.75 II Pl.Mantrvse Vernier Cond . . 2.55 17 PLMeetreee Vernier Cond.. 2.75 23 Pl.Meatrete Vernier Cend.. 2.85 43 PLMeatrese Vernier Coed.. 3.65 II PI U. S. Tool 3.35 23 Pi. U. 8. Tort 3.65 43 PI. U. 8. Tool 4.10 HEATH'S RADIAN VERNIER CONDENSERS 13 Plate $4.75 23 Plate 5.25 43 Plate 5.95 VARIOCOUPLERS Fisher, 180° $2.35 Shamrock 2.65 Sleeper, no taps 3.75 Workrite 2.95 Gillflllan, small 5.95 Gillflllan, large 7.45 Path* 3.25 Genuine All Wave 5.35 Cockaday Coil |.85 Unxld, 180°, Bakelite 1.95 VARIOMETERS Fisher, large, 600 meter Shamrock 2.65 Sleeper 5.95 Workrite 2.95 Gillflllan, small 495 Gillflllan, large 7' 45 Pathe 2'.85 PHONES Neroo $2.35 Pacent 3.45 Brandes Superior 4.85 Federal 4.95 National Baldwin Type C 7.95 Dr. Seibt, German Phone, 6000 ohms 5.85 Western Electric 8.85 Ambassador 3.50 Potter Precision 4.25 Wiener Phones 3.95 TRANSFORMERS Acme Audio and Radio $ 3.90 AllAmerican (all ratios) 3.90 Federal No. 65 5.95 Modern 495 Thordarson 3^5 Erla Reflex and Audio 4.45 Akxacy 3.35 Modern Push-Pull 10.75 Como Push-Pull 10 75 Rasla Transformers 3.95 CYCLONE BATTERI Snail 22'/i Volt Largo 22'/2 Volt Medium 45 Volt... Large 45 Volt Large 22'/2 Volt Eveready Battery Large 45 Volt Eveready Battery. Small 22'/* Volt Eveready Battery Eveready "C" Battery, 4'/; Volt. ES .$ .75 . 1.75 . 2.30 . 3.45 . 2.35 . 3.65 . 1.15 . .55 HARD RUBBER PANELS X 10 X 12 X 14 X 18 x 21 x 24 ► .70 .90 1.00 1.40 1.65 1.85 MAHOGANY CABINETS 7 X 10 $2.45 7 x 12 2.66 7 x 14 2.80 7 X 18 3.05 I * J' 3.35 7 X 24 3.65 Bell Socket, Bakelite Panel Mounting , Antes 6 ohm Rheostat Amsco 20 ohm Rheostat '""see 30 ohm Rheostat Amsco 400 ohm Potentiometer, Cutler-Hammer 6 ohm Rheostat. Plain Cutler-Hammer 6 ohm Rheo. ■ -ILECTRAHOT Solder Iron... ew improved Cockaday Coil., $ .69 .95 1.15 1.25 1.40 .95 1.20 2.50 5.50 MISCELLANEOUS Path* Pulsiformers $8.50 New Improved Cockaday Coils, silk wound 5.50 Cutler-Hammer 30 ohm Rheostat, Plain 1.20 Cutler-Hammer 400 ohm Potentiometer 1.20 Filkostat 1.85 Bradleystat or Bradleyieak 1.70 Bruno 14 Tap Inductance Sw.. .70 Sta-put Phone Plug 35 Phone Plus for 6 pr. Phones.. 1.25 Phone Plug for 2 pr. Phones.. $ .60 Single Circuit Jacks 35 Double Circuit Jacks 45 V Dials, Fada Type , , .45 3" Dials. Fada Type 3a Triple Sockets. Fada Stylo! 2 65 Marked Eby. Bind. Posts. Ea. .17 Ambassador Coil 5.95 Shelton Midget Vernier 1.40 Freshman Grid Leak & Cond. .75 The New Genuine Guaranteed "Shepco" "All Wave" Jr. Trade-Mark Patents Granted and Pending Non-Radiating DX Coupler Combination Flat and Bank Wound All the SELECTIVITY of TUNED RADIO FREQUENCY at a SMALL FRACTION OF ITS COST. Like its companion, the 3000 meter Capitol "All Wave" Coupler, Sr., it may be used in a single circuit with the added feature that it may be used in a double or triple circuit. Used in the "All Wave" triple circuit, the "All Wave" Jr. is guaranteed not to radiate and to bring in distant stations clear and loud on one tube. Log your stations and get them at the same setting every time. Only one dial to tune. "All Wave" Sr. "SHEPCO" " ALLWAVE " Jr. $7.00 150 to 3000 Meters Guaranteed Wave Length Eliminates use of all variometers, variocouplers and loading coils. Permits building most efficient, sharp toning, load, long distance receiver at lowest cost. ^*«uj*r "All Wave" Jr. $6.00 150 to 2000 Meters Guaranteed Ware Length READ THESE RESULTS OBTAINED WITH "ALL WAVE" COUPLERS F. S. Thompson, De Kalb, Mo. "Picked up London, England, so it could he heard through two rooms." J. VV. Sutcliffe, Providence, R. I. "Got KFI, Los Angeles, Cuba, Porto Rico and Nebraska. Convinced of quality of your product." J. M. Bleuvelt. Dallas, Tex. "For selectivity it is the goods. I can tune out and in any station." Set of six efficient hook-ups packed with every "All Wave" Coupler or mailed on receipt of 10c in stamps to cover cost of mailing. On sale at all dealers in standard radio parts or sent direct on receipt of price. ABSOLUTE MONEY BACK GUARANTEE. Shepard-Potter Co. INC. Plattsburg, N. Y. The Prices Quoted Below Deliver Goods to Your Door HOW TO ORDER — Write your order plainly; stile number, description and price of it<>nis wanted. Send Poet Office or Express Money Order, personal check or bank. draft. REFERENCES: Dun's. Bradrtreet's or Cera Exchange Bank. JACKS AND PLUGS a, Jacks are polished nickel constructed with pure silver contacts. D118 One spring open circuit $ -39 D119 Two spring closed circuit ■^S D120 Round plug as illustrated .O Audio Frequency Transformers The following transformers are guaranteed standard makes, and will produce very efficient results. D63 Dietzen 3 to 1 Ratio $3.95 064 Dietzen 5 to 1 Ratio 3.95 D65 Dietzen 10 to 1 Ratio 3.95 066 Acme Audio. $4.25 D67 Amortran 5.95 D 68 General Radio • 4.65 D69 Modern Audio 4-1 4.65 HONEYCOMB COIL MOUNTINGS D140 2-coil mounting $2.85 D141 3coil mounting 3.79 D142 Single coil mounting 40 D143 Receptacle for single coil mounting 50 DIETZEN SUPER HEADSET D181 2200 Ohms $2JS Reg. Price, $5.00 per Pair. Since we are wholesale distributors for this wonderful headset we pass this bargain on to you. The Tone quality is of unusual volume. These phones can be used as a loud speaker unit. Sold with a money back guarantee, if not satisfactory. MISCELLANEOUS DI63 Spashettl Tubing, per yd % .99 D 164 Synthetic Crystal 30 D 1 65 Ground Clamps 17 DI68 Black Rubber Binding Posts 05 DI67 Nickel Plated Binding Posts. 2 for 05 DI68 No. IS Annunciator Wire, half pound coil .39 DI69 6 ft. Phone Cord with Tips 79 DI70 20 ft. Extension Cord with Tips 1.95 DI7I Wall Insulators. Porcelain 05 DI72 Tubular Porcelain Lead-in Insulators. 6-in. .10 D 173 Relnartz Coil 1.45 0174 Cockaday Coil 2.45 DI75 2 in. Dial and Knob 25 D 176 3 in. Dial and Knob S5 DI77 Switch Arm. Tapered Knob... 19 VARIABLE AIR CONDENSERS These condensers are nude of Leery aluminum plates, high grade bakelite ends. DUO— 21 PL. .0005 Mfd.$l.7S Dill— 11 PL, .00025 Mfd. 1.25 01 12 — 3 PL, .00005 Mfd. .99 0113 — 13 PL. .001 Mfd. 2.23 Vernier Variable Condensers These condensers axe made of a.eiry aluminum plates, high grade bakelite ends. DU4— 14 Plate Vernier with knob and dial $2-95 DllS— 26 Plate Vernier with knob and dial 3.4S DllS— 43 Plate Vernier with knob and dial 3.JS INDOOR LOOP AERIAL D7C. Can be assembled by anyone in five minutes; all wood parts, wire and binding posts included, complete, while quantity lasts 79c DOUBLE PHONOGRAPH ATTACHMENT This attachment fits all phonographs: will take any headset. It converts your phonograph into a load ker. D132 Double attachment % JSS D180 Single attachment fits any single phone unit to be used on phonographs 49 RADIO CABINETS Highest grade Mahogany piano finish Cabinets. Hinged top. These cabinets are being sold at less than one-half regular value. D57 Wood Cabinet: r '.!>". Each $2.95 058 Wood Cabinet: panel , 3,45 D59 Woo. 060 Wood .. 4.45 ... 4^5 D62 Wo.-. .. a.75 v above cab.. xH. 7x10. 7x12. .25e .30* ,vv 71 Cortland t Street NEW YORK, N. Y. America's Greatest R^dio Mail Order Houi ELEVEN NEW YORK STORES