Radio Digest (July 1924-Apr 1925)

18 RADIO DIGES T— Illustrated July 19, 1924 Questions and Answers Super-heterodyne (S417) WRV, Hensler, N. D. I have built a super-heterodyne and can't get it to work properly. I can only get a faint sissling and a squeel by turning up the rheostat. I've checked everything, but O. K. When hooking the phones and a "Pi-volt C battery in series I can get a click most anywhere, but mostly by touching the common — , and the 45 and 90 + . Should this be possible when not connected to any batteries and no filament lighted? Also this frying remains when filaments are turned off. When touching a micadon about, .002 mfd., should there be a click when making and breaking the contact? These are all foolish questions, but one can't ask the first man that comes along on the farm for this the reason of asking you. Thanks for some real information how to make it •work. A. — We have carefully noted action encountered in operation of your superheterodyne receiver. The click heard when connecting phones and battery in series is normal and due to capacity effect between wiring. The frying sound would indicate a defective transformer, condenser or tube socket. It will be necessary to test each unit for possible opens, shorts or leaks. It is quite impossibile in your failure to submit a diagram of circuit to determine definitely the source of your limitations. The circuit in question in all of its modifications is some task for the average layman and skill both of construction and operation are essential to realization of its superior attributes. PATENTS Procured. Send sketch or model today for examination, prompt report and advice. No charge for preliminary advice. Write for free Booklets "How to Obtain a Patent" and "Invention and Industry" and blank form on which to disclose your idea. Highest references. Promptness assured. Clarence A. O'Brien, Registered Patent Lawyer, 2002 Security Bank Building. Directly across the street from Patent Office, Washington, D. C. Don't You Get Tired of only hearing LOCAL stations on your Crystal Set? There s musio on Four aerial every night from stations f ar'away. f you want to'hear i t without buying a tube eet, WRITE ME TODAY. LEON LAMBERT 601 South Volutsia Wichita, Kansas ill f ~ ! DURHAM I Variable Grid Leak Ac dealers, or postpaid Durham &. Co., 1936 Market St.. Phila. You Can Also Charge "B" Batteries at Home! APCO "B" Battery Charger i a worthy ally to the successful APCO Charger for "A" batteries. Renews any 24 or 48-volt wet "B" battery in ten hours — without disconnecting set. It's noiseless, clean and easy to hook up as an electric iron. Complete with wires ready to use, $10. Write for interesting circular and nearest dealer's name. APCO MFG. CO., Or St, Providence, R. I. v * j** v^t^rft v * v Two tubes do the work of five Shamrock-Harkness set does this. Send 10 cents for booklet SHAMROCK MANUFACTURING CO. Dept. 21-A, Market St. Newark, N. J. **** V^*£* ^*T* * Choke Coil (8293) DEH, Bellefontaine, Ohio. As I am a weekly reader of the Digest I would like to have you tell me how much wire must be used, what direction must each winding be wound, what size and shape core, and other data for the construction of a one and one-half henry choke coil, to be used on a ten Watt Transmitter? A. — In the construction of a one and one-half henry choke coil it will require a core 2 inches square with 4,000 turns of number 26 wire. Resistance Coupling' (8508) ERS, Montreal, Can. Thank you for your kind reply to my letter number 08151. The request was briefly this: If a twostage audio frequency amplifier can be converted into a two-stage Radio frequency resistance coupled amplifier, please give me full instructions how to re-connect as in connection with 3-coil circuit. If you could give me the full circuit I would be obliged, also how to wire the two-stage amplifier. Pleased to say Miloplex King III with "CRYSTAL Sets Tested 600 Miles." You can now get a genuine Lambert Long Distance Crystal Radio Set for only $4.98. Partifulars free. Leon Lambert, 501 Volutsia, Wichita, Kansas. SELL Coal in Carload Lots. Side or Main line. Experience Unnecessary. Earn week's pay in an hour. Liberal drawing account arrangement. WASHINGTON COAL COMPANY, 945 Coal Exchange Building, Chicago. OSCILTONE RADIO TUBES GUARANTEED for 1000 Hours Life Replaced irrespective of purchase place. All types. UV-199 on Stand and Socket. No Special Adapter or Socket required. If Dealers cannot supply, apply direct distributors. R-C MILLS RADIO CORF. 303 FOURTH AVE. NEW YORK CITY Sales Agents Wanted CFiVes* Titektanlelourffe%&l/fralS JL^JjtCjjfJCQ fOn Crystal Sets' t Results truly amazing". Everyone aston. I" ished. H. Harryman, Opdyke, 111., says: "I have.heard 26 stations, most distant 825 miles, Schenectady." H. Lapsley, Council Bluffs, la. , says: "Second night I got KDKA, _ E. Pittsburgh." You can't doubt your own 1 ears. Listen in on STEINITE at my risk. *50c Each or 3 for $1.00 STEINITE opens up new possibilities for crystal Beta. Don't delay the Radio treat in stora for you. Send Dollar Bill today for 3 Crystals and! free hookups. None genuine unless stamped "S" Two big Atchison Banks guarantee prompt refund If not delighted. Literature FREE. STEINITE LABORATORIES 9 Radio Bldg., Atchison. **»—>mf ULTRADYNE TRANSFORMERS 1 Input Transformer and 3 Intermediate Transformers Oscillating Coils, $20.00 $4.00 Tuning, per pair. Full instructions and Blue Prints furnished with each Kit. Absolutely guaranteed. These transformers are suitable for any Super-Heterodyne circuit. Put up in handsome Kit display box. Special discount to dealers. Prompt delivery. Write for special circular. SYPHER MANUFACTURING COMPANY 1524 Fernwoocl Ave., Toledo, Ohio iiiiiiiimmMiMiMimiMiiiiuiiMiiiiiiuiMiiMiiiiiiiiiiiiiiiiiiiiiiiiiiiiimiiiiiiiiimiiiiiiiii The Dubilier Duratran The radio-frequency transformer that amplifies uniformly over all broadcasting wave lengths. Made to satisfy the man who knows radio. DUBILIER CONDENSER AND RADIO CORP. 43 "West Fourth Street, New York IIIIIIIIUIIIIIIIIIMIIIIilllllllllllllllllllUllltllfllllllUlllllllllllillUIIIIIUIIIIIIIIIIIIIIUIIIIIII two stages is still the pride of the neighborhood. Can you also supply value and character of inductance between variometers, Q. & A. 6927, Kopprasch circuit, March 22? A. — We do not recommend resistance coupled Radio frequency as the amplification per stage realized in the method is so small. Tuned Radio frequency amplifier as indicated in circuit of your inquiry is superior. The inductance coil between the variometers of the Kopprasch circuit is a forty PATENT Attorneys. Patents. Booklet free. Highest references. Best results. WATSON E. COLEMAN, Patent Lawyer, 644 G Street, Washington, D. C. FREE — Log Book with each purchase FACTORY GUARANTEED MDSE. BY MAIL Genuine New Radiotron or Cunningham Tubes UV-199— 200— 201A—WD-11— 12 d»Q no C299— 300— 301A— Cll— 12 «J>«3 . UO Fresh Burgess or Eveready "B" Batteries 22% Volt large size $1.68—45 Volt $5.00 size $3.33 Write for Complete Price List STONE ELECTRIC CO.. 714 Pine St., St. Louis, Mo. All Mdse. F.O.B. St. Louis, Mo. Dept. D Super Crystal New Non-Metallic Housing Eliminates Scratches & Squealing Wonderful new crystal — has millions Of sensitive spots — long life — cannot short circuit. FITS ANY STANDARD DETECTOR At your dealer — otherwise send purchase price and you will be supplied postpaid. Ask for reflex circuit 120. rtjas. Freshman (o. Inc. \%ccx//ol Condenser s&oducts 106 Seventh Avenu«, New York City ' I » ■ t » » iiiiii ■ » « Bankrupt Stock Cunningham Regenerative one tube long range sets $9.00 Each Formerly sold at $32.50 No Circulars. Order from This Ad. This set with tube, phones, all batteries and aerial complete, <t01 C\C\ ready to use, for «P^.±.W Prepaid while they last. S. A. TWITCHELL 1925 Western Av., Minneapolis, Minn. fJhe^raffic Cop of the JHv-Z^ He arranges in orderly fashion the mass and jumble of Broadcasting Stations that are seeking entrance to your set and brings 'em in, one at a time, so you can enjoy them! Never reduces, but nearly always increases volume. Add a Ferbend Wave Trap to your set and "Police" your reception. Regulate the Traffic! Guaranteed to tune oat any Interfering station. The price 1 3 $8.50. Shipment la made parcel post C. O. D. plug a few cents postage. If you prefer, send cash Id full with order and we will ship postage prepaid. Send as your order today. „„orvm FERBEND FERBEND ELECTRIC €77^ t COMPANY ta/ve JAah> 23 e. south J Water St. Chicago, 111. 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 new 1024 Model F I The new "Red-Head" Jr. $f5 ^O Per Pair QK OH Per Pair *4>O.OU Complete I «pi>.WU Complete "Red-Heads" sent prepaid on receipt of price if you are unable to get them at your dealers. THE NEWMAN-STERN COMPANY DEPT. R. D., NEWMAN-STERN BUILDING. CLEVELAND, OHIO turn coil number 22 dec. tapped at every tenth turn and is wound on a tube to fit easily on stator opening of variometers, as it rests upon them. "We are congratulating you upon your Miloplex, King III, receiver and its popularity. YOU NEED NAMES! I've had letters from 50,000 Radio fans. Can furnish names in any number and from any state or city desired. Write for prices. Leon Lambert, 501-F Volutsia, Wichita, Kansas. FREE Attractive Radio Catalogue Just write your address. You need not Include stamps. NOVICK RADIO CO. 1522 Charlotte St. Bronx, New York City What About It? Isn't it about time to stop experimenting with multiple control circuits and build one that, combining ease of assembly and operation, loudness, clarity and selectivity of signals, as well as beautiful appearance, is excelled by none? THE ELGIN SUPER-REINARTZ RADIO RECEIVING SETS Embodies all the advantages of the well known Elgin Keinartz (the set which was largely responsible for the popularity of this wonderful circuit) and many others. It Is much louder, more selective, reciuires no storage battery, and can be used with excellent results on a short or loop aerial. It has brought in 2LO England, and California stations two thousand miles from Elgin, clearly and without interference on a loud speaker with only one tube, and that while our powerful local station was broadcasting three miles away. Could you ask for more. Send 2-cent stamp for circular giving one, two and three bulb hookups of this remarkable circuit. ELGIN RADIO SUPPLY CO. 207 East Chicago Street ELGIN, ILLINOIS KEYSTONE RADIO LIGHTNING ARRESTERS $1.50 At All Dealers Buy your Keystone Arrestor today — install it according to instructions supplied, and forget about lightning. Made of Bakelite — weather-proof. No vacuum to lose. Approved by Underwriters. At all Dealers, $1.50. Manufacturers of over a million Lightning Arrestors ELECTRIC SERVICE SUPPLIES CO. 17th and Cambria Streets, Philadelphia 53 W. Jackson Blvd., Chicago 50 Church St., New York a