Radio Digest (Oct 1923-July 1924)

February 16, 1924 RADIO DIGEST — Illustrated More Details on Selective Tuning Coil Results Obtained Are Satisfactory to Many Since the appearance of the special tuner and hook-up in the January 12 issue of the Radio Digest, many letters have been received by the author of the circuit, commenting on the work it will do 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 and asking for further details. Many fans have built this tuner and have had unusual success with it. A letter from "W. J. Gilmore, of Derby Line, says: "I have built the special tuner described in Radio Digest and it works fine and I am getting great results. What is the circuit, single or what?" Others who have built the tuner and hooked it up with a detector tube alone want to know how to add amplification. The diagram herewith gives details of the tuner and how to place it in the circuit with two stages of audio frequency amplification. A UV-200 tube is used for the detector and UV-201A's for the amplifier. There is no question but what HOOK-UP IN WHICH COIL IS USED TO OTHER ROTOR BEA.RIN6 -=1TM I'lTh b 9o-ieov 10 TARS EVERY "7aTUre.N CORRECTION FOR FRIDAY TUNER For the benefit of fans who have tried Mr. Friday's circuit, described in your magazine of January 12th, under the heading, "Three Tube Set Does the Work of Five," I would like to point out two confusing mistakes in the printed circuit. First, in describing his coupler, he tells that the taps are taken off on the primary next to the secondary, while in the hookup he has them on the extreme end. Second, the tickler leads must be reversed. If one studies the circuit that will be seen at once, for as he depicts it, the windings are directly opposed to each other. I have constructed this coupler and I know whereof I speak. I crossed over the antenna lead to the second tap switch and connected first switch and secondary switch to ground. My greatest trouble, which was my own fault, was in the tickler. I used a 180 degree rotor from another coupler and failed to reduce the windings to the number stated,' but after I corrected my error I am getting wonderful results. I live 30 miles from Pittsburgh and bring in KDKA in loud speaker volume on detector alone. I get Chicago, Omaha and New York stations on loud speaker with two stages of amplification using WD-ll's throughout. — Roy N. Hill, Leechburg, Pa. the small dry cell tubes can be used with equal success. Radiophans building their own sets desire a more selective tuner and the one illustrated comes pretty near to being perfection in that respect. While this tuner works especially well In the circuit III Improved again/ The MAGNATRON DC-201A— even better than it was before! It and the MAGNATRON DC-199 are the two outstanding per*formers among tubes today. At the new list price of $S, these tubes are also out Stan ding values. You can no longer afford to use inferior tubes. Your Dealer Has Them! CONNEWEY ELECTRIC LABORATORIES 309 Fifth Avenue NEW YORK CITY 'Z01STURNI 1WTUKN PRIMARY AND SECONDARY WOUND IN THE SAME DIRECTION <j> G 4) shown, it can also be used as a standard variocoupler by using the secondary windings as a primary and the rotor as a secondary, or it may be used as an inductive variometer tuner similar to the Paragon circuit. The author is using one in a super-heterodyne with regeneration, and will say that it is so selective and the tuning so sharp that stations are difficult to find. In making the tuner, the primary and secondary windings are all wound in the same direction. A formica or bakelite tube is preferable for both stator and rotor windings. If you cannot obtain tubes of either of these materials and must use a cardboard tube, handle it very carefully so that it will not get out of shape. Coat it with collodion or paraffin before winding The Dependable Radio Receiver FADA "ONE SIXTY" with the NEUTRODYNE CIRCUIT The PADA "One Sixty" is the four-tube 'N'eutrorlyne radio receiver that in selectivity, volume, distance and clarity equals the best results of any five-tube set of any type or make. Owners say. "If we don't get 'era on the loud speaker, we don't count 'em." Consistent performance on loud speaker from, stations 1500 to 2000 miles away and sometimes much further. Price $130 at dealers Extra for tubes, batteries and 'phones F. A. D. ANDREA, Inc. 1S81 Jerome Ave., New York City x=* -^v. r> i <z> No. 804 $15= complete with Baldwin Type C Loudspeaker unit. "> At Last! tKe true, pure voice of RADIO >j The "Madera" Die-cast Wood "CLEARSPEAKER made from an artificial wood, twice as dense as natural wood, with acoustic properties that will give your radio set a power and tonequality you never dreamed possible. If your Dealer does not have it, write us, giving his name and address. American Art Mache Co. 347 West Austin Avenue CHICAGO BEARING FOE ROTOR. SHAFTS BETWEEN SECONDARY COIL on the wire. This keeps the moisture out. The windings may be coated also with the same material, but this is not necessary. Never use shellac. The rotor tube must be as large in diameter as possible, provided it will rotate inside of the 4-inch tube. This will make the rotor windings come close to the secondary windings and is the secret of Radio frequency with this tuner. The rotor end of the tube should be /S WE REPAIR THE FOLLOWING RADIO TUBES Dealers and Agents write tor Special Discount Mail Orders Solicited and Promptly Attended to WDII ? WD-I2S OUR SPECIALTIES S5 WATT (TRANSMITTERS UV-199 $3.50 UV-200 2.75 UV-201 3.00 UV-201A 3.50 WD-11 3.50 DV-6 3.00 UV-299 3.50 C-299 $3.50 C-30O 2.75 C-301 3.00 C-301A 3.50 WD-12 3.S0 DV-6A 3.S0 H. & H. RADIO COMPANY P. 0. Box 22-A Clinton HiU Station NEWARK, N. J. The New MCircuit* & Columbia cMoulded Variometer This variometer, moulded in genuine black bakelite, represents the latest advance in construction for reason that it permits ALL of the new hook-ups of present and future. Stator is moulded in two halves with no metal bearing post in front nor in rear. Green silk wire used throughout. Silk pig-tail connections. Latest suggested hook-ups with each instrument. <i»C PA No. C109A 3>D.DU COLUMBIA RADIO CORPORATION 15S N. Union St. Chicago, 111. JIP^ w Good Rules to Observe in Building a Receiver eap parts with poor electrical qualities and sloppy workmanship which add resistance and cause leaks in the circuit are responsible for virtually every failure In Radio. An amateur should exercise every effort in hooking up a set, so as to make a good job of it. Use good parts, arrange them neatly and efficiently in the cabinet, keep all wires well separated and exercise great care in soldering connections. If those rules are followed, success is almost certain. toward the detector tube in order to have short leads. The wires for the plate of the detector tube and the first transformer, or phones, are fastened to the plates or rotor shaft bearings between the secondary windings on the outside of the 4Tinch tube. The taps on the primary and secondary are taken off the top, bottom or side of the coil where it will be most convenient in the make-up of the set. Follow the diagram closely and you will be surprised at its action. There is nothing secret or extraordinary about this tuner. It gives unusual selectivity by having both primary and secondary tapped and by placing the usual condenser across the secondary. Perfect volume control is obtained through the balanced rotor windings and close coupling of the secondary. I would be gratified by hearing from those who try this tuner and circuit, what success they have. If you are not successful, perhaps I can help you out. — W. L. Friday, 9530 S. Robey Street, Chicago, 111. TEN REALBIG REASONS WHY YOU, Yes, YOU Should TODAY ORDER and ALWAYS USE WHERE I GO BY RADIO The New Radio Record Book Now Being Used Every Night Everywhere 1. It is Handy, Complete, Convenient. 2. Shows at a glance When, Where, How and What You Heard. 3. Every line a complete record, giving Date, Hour, Weather Conditions, Station Call Letters, Location, Kind of Program, "Tuning In" Combinations, etc. 4. How to Measure Distances and Get Best Service. 5. Accurate Official List of Broadcasting Stations corrected to November 15th. 6. Special copyrighted symbols make recording easy. 7. Enable you to keep permanent records of everything interesting you hear, such as when Lloyd George. Woodrow Wilson, President Coolldge spoke, etc. 8. Supplies at Small cost what every "Ra-Ow!" has long been wanting. 9. Endorsed and used by both amateurs and professionals Everywhere. 10. New, Unique Radio Record System, with an Idea that appeals. It's the Idea and not just the number of pages, each 8x11 inches, that makes It worth while. Now "Listen In" on This. The names and addresses of the First Person from each of the First Ten States, and the Last Person from each of the Last Ten States, received by us to February 9th. inclusive, sending $1.00 for one Holiday, or two copies Popular Edition of Radio Record Rooks "Where I Go by Radio," will be published later in this Faner. This Is a test of the "pulling power" of this advertisement. Why Not Be First and see YOUR name in print? RADIO BOOK DEPT. PROGRESS PRESS Union, South Carolina, U. S. A. >|85 A EACH A. H. Halloran, editor of "Radio," tested the Bradleyleak, and writes: "I have made several tests on the Bradleyleak. It is the only variable grid leak I have tried that really varies," All the leading radio authorities praise the Bradleyleak. It has solved the grid-leak problem. Try one on your radio set, tonight. ALLEN-BRADLEY CO. 290 Greenfield Ave., Milwaukee, Wis. Mfrs. of the Universal Bradleystat Brad^deok THE PERFECT GRID LEAK.