Radio Digest (July 1924-Apr 1925)

August 2, 1924 RADIO DIGEST -Illustrated 15 A Homemade Six Tube Superdyne Receiver Part I — Hook-Up and Instructions for Winding Coils By M. C. Williams +i ff ~i 1 1 it +J-i i i i i i i i i + 1 ntnlll'rn'T1'1'1 /\_ 6V 2 2KaV HOMEMADE coils are used with this set and they are of the ordinary kind. The secondary or stator should be 4 inches in diameter and wound with 25 turns of number 22 dsc. wire The coil is run on at one end, beginning ROTOR 13 TURNS "22 D S C STATOIE 25 TURNS "Z.'Z. O S . C PLATE INDUCTANCE 2,0 TURNS *ZZ DSC % inch from the rotor shaft and % inch rom the lower end of the tube. The rotor is of the round ball type wound with 25 turns' of number 22 dsc. wire, commencing at the outer edges and winding toward the center, leaving a space at the center for the shaft. The "Goode" Two o-One Le Ton d'argent c a v. a s BY MAIL ONLY 239 Postpaid QUARTER AMPERE AMPLIFIER— DETECTOR RADIO TUBE GUARANTEED SATISFACTORY $2.39 6.42 All "GOODE" Tubes Sold Direct to the Consumer — No Dealer Profits ONE — "Goode" Detector-Amplifier THREE — "Goode" Detector-Amplifiers (Ail postage prepaid) The "Hondo" Two-o-One A Tube amplifies or detects. It is a quarter ampere, aix volts, standard baso silvered lube. >8 or postal money order or New York draft to The Goode Tube Corporation Incorporated EVANSVILLE INDIANA 67W.V. AA — Aerial wave length condenser for balancing. After it is once adjusted for the particular type of aerial it need not be touched again. Many use the small fixed condensers after the one best suited has been tried out. A — Variable condenser, .0005 for wave length of station to be tuned in. B — Special coupler, stator has 25 turns of number 22 dsc. wire wound on Vz inch from bottom edge and rotor shaft. Tube is 4 inches in diameter. C — Rotor (feed back stabilizer) 18 turns on each side of number 22 dsc. wire connected on the inside in series leaving space on outside between windings. P — Plate inductance. Pour-inch tube with 30 turns of number 22 dsc. wire, starting at' y2 inch from the top edge and rotor holes if an old variocoupler tube is used. D and E — Rheostats. G — Variable grid leak. I — Fixed condensers, .002. j — Transformers, same ratio, 9 to 1. K — Push and pull transformers. B'^bV Similar in design and size to the stator mentioned wind a coil of 30 turns of number 22 dsc. wire, commencing about Vz inch from the top. The illustration shows these coils. Very good results should be ob'tained by connecting the loop to the aerial and ground binding posts through a small fixed condenser. Better results, however, may be obtained by grounding the negative side of the filament and connecting a small aerial strung across the room to the stationary plates of the first variable condenser. Tubes may be arranged in any manner to suit the fancy of the builder, but re HAKSEN BIRD CAGE LINE 4-TUBE PORTABLE RECEIVER '.50 COMPLETE "Don't forget that this is not an ear phone — but a loud speaker portable." Here is the "NIGHTINGALE PORTABLE" in a fine case ready to walk away with. Take it with you on your Vacation, Auto Trip or to your Summer Camp or Home. When you come back with it, take it out of the case and use it as a home Radio Receiving Set. It is complete in all details including aerial, batteries and collapsible loudspeaker. It is only 16%x9V£x8V& inches in size and weighs 25 pounds. It is ready to operate when you get it and costs $92.50 NIGHTINGALE— 4-Tube Radio Receiver without accessories 32.50 MOCKING-BIRD — 6-Tube Indoor-Loop Radio Receiver without accessories 90.00 Write for Literature Dealers — A wonderfully attractive proposition JOBBERS — We want one responsible and activo distributor in each state. ^National Distributor DISTRICT DISTRIBUTORS United Auto Supply Co Columbus. Ohio Reins & Meiss Co Cincinnati. Ohio Penn. Niqhtinnale Co Bellovue. Pa. Badger Radio Co Milwaukee, Wis. Phil Gross Hdw. Co Milwaukee, Wis. Colliding Mfg. Co Milwaukee, Wis. member that the leads which carry Radio frequency current must be very short and direct. The wiring of the filament Ttnd other parts at more or less ground potential should run near the front of the panel and the rotary plates of the variable condensers should be as near to ground potential as possible to reduce stray capacity from the hands of the operator. All wires from the grid and plate circuits should be far back from the panel and separated from themselves and everything else as far as possible. A great deal depends on the construc UIIIIUIIUUUIIUIUUIIIIIIIIIIIIIIIIIIIIIIIMIIUIIIIIUItlUIIUIUIUUIIIUIUUIIUIIIIIIUIUUH 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 IIIIIIIIMIMIIIMIIIIIIUINIIinilHIIIIUHIIUIIIIIMIHIIIIllIIIMlllIIIIIIMIIIIIIIIIIIIIIMtlllllMII Charges 120 Volts of "B" Battery IN SERIES Up to 120 Volts "B" battery in series, 6 Volt Radio "A," and automobile batteries can be economically charged with the F. F. Battery Charger. Simple and durable. No costly bulbs used. There are many other interesting features you should know. PRICES: Type AB, $20.00: Type 6 for "A" or Auto Batteries, $16.00; each slightly higher west ot the Kockies. Write for literature THE FRANCE MFG. CO. 10321 BEREA RD. Cleveland, 0. PARTS REQUIRED 1 Special Coupler, 1 Plate Inductance, 5 Rheostats, 4 Fixed Condensers, 1 Variable Grid teak, 6 Sockets, 1 Cabinet, 7 x 26, 1 Panel, 7 x 26, 2 Variable Condensers, .0005, 2 Transformers, 1st and 2nd Stage, 3 3-inch White Dials, 7 Engraved Binding Posts, 1 Input Push and Pull Transformer, 1 Output Push and Full Transformer, 2 Jacks, Necessary bus-bar and spaghetti. Total cost about $60.00. tion of this stage, whether it really beats a regenerative detector and two-stage audio or not. The main thing to remem (Continuned on page 16) r Success Comes in Cans, Failure in Can'ts Roosevelt or Bryan or somebody pointed out "that the fellow who said it couldn't be done was continually being awakened by somebody going and doing it." Millions of people night after night, at home, in camp, on vacation trips and other places are enjoying their Radio sets — they know that it can be done. There is a definite place in everybody's life for Radio summer and winter. It's no longer a question of do you need Radio — it's how can you get along without it? KEYSTONE RADIO LIGHTNING ARRESTERS $1.50 At All Dealers Buy your Keystone Arrester today — install it according to instructions supplied, and forget about lightning. Made of Bakelito — weather-proof. No vacuum to lose. Approved by Underwriters. At all Dealers, $1.50. Manufacturers of over a million Lightning Arresters ELECTRIC SERVICE SUPPLIES CO. 17th and Cambria Streets, Philadelphia 53 W. Jackson Blvd., Chicaso 50 Church St., New York