Radio Digest (Oct 1923-July 1924)

192 Jt RADIO DIGEST — Illustrated 21 The Latest in Super-Heterodyne Hook-Ups Part IV— Seven Tube and Filter Circuits IttEG By H. J. Marx 1MEG A FAN writes a long letter asking which is best, the super-heterodyne or the neutrodyne. There is little doubt on the subject, the super-heterodyne circuit when the apparatus is properly designed, constructed and assembled will be far superior to any of the circuits at present known. But the problem of proper design and construction still retains a few kinks for complete solution. In addition, Figure 9. the panel layout. It is a foregone conclusion that when the panel layout is the first problem to be undertaken, the efficiency of operation is neglected. Greater Selectivity In most cases the volume of the superheterodyne will not be any more than that of the neutrodyne, but its selectivity should be infinitely greater. The entire 12,000 OHMS lc\000OHMS Figure 10 the assembly of a set with the numerous tubes required is one of the most difficult problems that the* average fan has ever undertaken. The best procedure is to first assemble the apparatus on a flat board,~ hook it up and make the necessary changes until it is working right. Then start figuring on range of the* two variable condensers should be available for tuning the stations as desired. If the condensers are too large or have too much dead tuning area, the adjustment over its working range is unnecessarily critical. If the capacity is too small some stations can not be received. If the transformers are not Standard Merchandise Only « S. HAMMER RADIO CO. 303 Atkins Ave. Dept. D. Brooklyn, N. Y. Anything and Everything in Radio A New Simple Way to Build a Neutrodyne Set We give you the entire set completely wired in a Genuine Mahogany Cabinet, with the exception of the Neutroformers and Neu C» !■< •■* fifi trodons, which we supply and you mount yourself, for the W »^f 1^"" low price of %J %J ABSOLUTELY GUARANTEED $150 Freed-Eisemann Neutrodyne Model NR-5 Special $127.00 None Shipped C.O.D. $80 Freed Eisemann Parts for 5 Tube. Neutrodyne <£££ f\f\ Set. K. D. 50 ipOD.UU None Shipped C. 0. P. PHONES $ 5.00 Tumey, 3000 ohms..$ 2.75 12.00 Western Electric . . 8.75 6.00 Brandes Superior... 4.75 12. 00 Baldwin Type C 7.95 7.00 Federal 4.85 8.50 N. & K. Phones 6.60 • 5.50 Strombei'K Carlson... 4.50 12,00 Dr. Seibt 6000 ohms. 5.75 RHEOSTATS Fada 30 ohm Federal 25 ohm.. Amsco 6 ohm. . . . Amsco 20 ohm. . 1.00 1.50 l.OO 1.25 1.30 Amsco 30 ohm 1.50 1.50 '.90 1.00 2.00 1.85 1.85 2.00 Cutler Hammer 6 ohm Ver Cutler Hammer 30 ohm PI Klosner 6 or 30 ohm. Patent 6, 20 or 30 ohm Filkostat Bradley-Stat Bradleyleak Ermcostat .90 1.25 .85 1.00 1. 10 1.15 1.15 .80 .90 1.85 1.70 1.70 1.70 LOUD SPEAKERS $30.00 Music Master $24.00 35.00 Magnayox 29.00 30.00 Herald 26.00 10. 00 Brandes Table Talker 9.25 17.50 Pathe 15.25 Baldwin Unit 4.65 Amer. Radiophone Unit ... . 3.95 Geraco Music Master Unit. 9.00 JACKS AND PLUGS Pacent Double Jack 70 Pacent Single Jack 60 Federal Single Jack 65 A 5 TUBE NEUTRODYNE wired complete Mahogany Cabinet; with Genuine Fada Parts i$85 Set, 00 Danstrom 6 Way Plug $1.20 Cico 2 Way Plug 55 Weston Plug 90 4 CIRCUIT TUNER Complete parts for the improved Cockaday 4 Circuit a^ _* ~A Tuner, exactly as ipCKvU specified b y Cockaday . . . iircultA^ m*t llMyra!$55( VARIABLE CONDENSERS ll-PLATE 00 Signal $1-40 50 U. S. L 1-45 80 Amsco I -30 23-PLATE 50 Signal 1-60 75 U. S. L 1-65 30 17 -PI. Amsco 1-65 50 Amsee 1.95 43-PLATE 75 Signal 1.65 25 U. S. L 1.80 50 Amsco 2.75 VERNIER CONDENSERS ll-PLATE 00 Hammarlund 4.95 50 U. S. Tool 3.50 50 U. S. L 3.10 00 Amsco 2.95 23-PLATE 50 Hammarlund 5.65 00 U. S. Tool 3.60 00 U. S. L 3.45 50 Amsco 3.35 43-PLATE 50 Hammarlund 6.25 50 U. S. Tool 4.05 00 Amsco 3.95 50 Amsco 17-P1 3.35 EXTRA SPECIAL!!! # $120 Fada 4 Tube Neu <Cnr*00 trodyne Set No. 160... •P*J3UU None Shipped C.O.D. . $5.50 Amsco 26-P1 $4.10 3.00 Compensating Condenser 2.65 DIALS AND SOCKETS 3" Amsco Bakelite 45 1" Amsco Bakelite 80 Bell Socket 65 Melco Socket •§» Triple Socket 2.50 Bakelite Socket *5 Ckelton Socket 65 TRANSFORMERS 7.00 Federal No. 65 5.35 5.00 Acme 3.85 5.00 AllAmerican 3.85 7.00 Amertran 5.60 4.50 Thordarson 3.75 12.50 Como Duplex 10.00 12.50 Modem Push-Pull.. 10.50 5.00 Erla 4.25 12.00 All American P. P. 10.00 4.00 Duratran R. F 3.35 5.00 General Radio 4.35 POTENTIOMETERS 1.25 Pacent 1. 10 1.50 Amsco 1.25 1.50 Cutler Hammer 1.15 1.50 Klosner 1.25 MISCELLANEOUS Pathe Phusiformers $7.95 Ambassador Coils 5.25 Cockaday Coils, Precision.. 4.50 Cockaday Coils, Eastern... 3.35 AMPLEX GRID DENSER. 1. 10 Lavite Resistances. 48,000 ohms I 10 $2. 00 Re inartz Coil 1 .40 Erla Crystals 95 Brach Lightning Arresters. . 1.75 ALL MAIL ORDERS SHIPPED PROMPTLY. Orders over $5.00 will be shipped prepaid. Money orders or C.O.D. Not insured unless insurance charges included. Write for Price List. properly designed very high or low wave lengths cannot be received without distortion or possibly not at all. It may often be found advisable to remove some of the rotating plates if the capacity is too large. If it is too small it may be easier to add a few turns to the inductance. Seven Tube Circuit A seven tube circuit is shown in Figure 9. This has four stages of super-audible amplification and one stage of audio frequency. Either the three or six volt tubes can be used. Changing the tubes around will soon indicate the arrangement giving the best results. All tubes are not good oscillators — likewise all tubes are not good detectors — so some changing around will help matters decidedly. l.-i is the oscillator plate coil, v.. • turns of number 22 wire on a 3% -inch tube. L-2 is the oscillator grid coil, with 42 turns of the size wire on the same tube spaced about %-inch from the plate coil winding. The pick-up or t-rid coupling coil, L-3, has 18 turns of the same wire on a inch rotor between the two fixed coils. The four super-audible transformers should be of the 6,000 meter type. The oscillator circuit should be well shielded from the rest of the circuit to prevent interference. Once the wave length settings on the tuning condenser are determined — tuning of this receiver becomes a simple matter. The oscillator condenser will have two points for each station. The potentiometer controls the volume of reception. An improvement would be to use a separate rheostat for ftie two detector and the c lator tubes, as the Betting of the single rheostat is somewhat critical. Pilter Circuit A filter circuit developed by Mr. Francis R. Elile of Philadelphia, is shown in ure 10. This is added between the ond detector tube and the primary of the audio frequency transformer. It is desirable to use a separate 22 li -volt B battery for this plate circuit in order to permit a complete elimination of stray impulses into the audio stages. The values of the various component parts are given in the diagram. Keep Lead-in Free from Metal Even though the lead-in wire is insulated, never let it touch against any metal. This means the cornice around the edge of the roof, the metal window screens or weather strip, or any other metal. In spite of the insulation, there will be leakage here, and trouble will surely result. Leakage will be greater during storms or damp weather and considerable difficulty may be encountered tuning in. It usually manifests itself by constant whistling and inability to clear up a station altogether. Schickerling SUPER D X AMPLIFIER-DETECTOR THE LAST WORD IN RADIO TUBES SPECIAL — DETECTOR THE TUBE YOU HAVE BEEN WAITING FOR The ideal "Detector" Tube for any set. Model S 200, 6 volt, V* amp. super detector. A very sensitive gas filled tube, consuming only Yi amp., plate voltage 22-45 THE NEW RADIO FREQUENCY TUBE Model S 800, 6 volt, consuming only Yi ampere. The first tube ever made especially for radio frequency use. Requires 90 to 150 plate voltage. A wonderful tube Ideal for Neutrodyne, Atwater-Kent, Superheterodyne, Grebe, Kennedy, Zenith, Crosley, Freed-Eiseman and all other good sets. $5.00 $6.00 $7 MODEL 700 Power Tube 6 Volt }-i Ampeie For loud speakers of any make. No set worth while is complete without this remarkable power tube, consuming only V4 amp. MODEL S 300 $5 IV2-V0U Dry Cell Tube, Yi amp. For one dry cell use. Fine detector on 22 to 45 volts and amplifies on 45 to 90 volts. MODEL 500 $5 Audio Frequency Super Amplifier 6 Volt }4 Ampere Exceptional volume. Amplifies at 45 to 90 volts. Fine detector on 22 to 45 volts. MODEL S 409 $5 3-volt Dry Cell Tube. 1-10 amp. Works well on two dry cells. Detector and amplifier 22 to 90 volts. All Schickerling Tubes have standard bases. Look for trade-mark: Signature of ConradSchickerling etched on tubes. Mail orders promptly filled. Send money order or check direct to factory, 313 Halsey St., Newark, N. J. No charge for postage. All tubes fully guaranteed and demonstrated at our laboratories and at our authorized distributors and dealers. The newly invented Schickerling Triangle Plate Vacuum Tubes mark a new departure in Radio progress. Sonorous, of magnificent volume, liquidly flexible, of splendid range, it lends itself with consummate grace to the greatest operatic arias, the simplest ballads or the passionate entreaty and faith of religious song. Free of distortion, a perfect revelation — and as you listen the richness of tone, the velvety smoothness of outpouring melody, will bring the singers themselves in all their magnetism and charming personality before you. DEALERS AND JOBBERS WRITE FOR DISCOUNTS Made Under License of United States Patent Rights by Schickerling Products Manufacturing Co. 313 HALSEY ST., NEWARK, N. J.