Radio Digest (July 1924-Apr 1925)

dy 26, 1924 RADIO DIGES T— Illustrated New Flewelling Super Portable Set Loop Made by Winding Wire Around Cabinet Using the diagram shown a set can be built very cheaply and is quite efficient. This set has a -very good range as I have picked up long distance on a loop antenna 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 inter ested 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, 510 North Dearborn St., Chicago consisting of eight turns of number 20 dec. on a 2% -foot frame. The hook-up is self-explanatory, but if, after it has been hooked up and the tube turned on, it fails to oscillate, which may be told by the squeals or frequency whistle peculiar to the super sets, change the connections to the plate coil. LI is the loop antenna, which may be wound around the cabinet for a portable set or it may be an ordinary loop as described before. D2 and L3 are honeycomb coils of 75 and 50 turns. Spider web coils of 35 and 25 turns may be used instead. It is best to have these coils variable but it is not absolutely necessary. CI is a variable condenser of .00025 mfd. or 11 plate capacity. C2 is a fixed condenser of .012 to .5 mfd. C3 is a variable grid leak and condenser. C4 is a variable condenser of .0005 mfd. While this condenser is not absolutely necessary it is a great aid for sharp tuning. A "WD 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 iimummiiiiiMiuuiiiiiiiiiiiiiiiiiiiniiiiiii iiiimiimiiiiiiiiiiiiiiuiiiiiiiimiiiiiiiiii The Dubilier Duratran The radio-frequency trans* former 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 mil miniiMimiuiitmii m imiiMn inn mil minium ilimimilMHiiimiitiilllllllimillllli LONG DISTANCE ONE-TUBE CIRCUIT HP no c2 \\ -mm\m- 12 vacuum tube was used by the author but the type UV-199 would probably be preferred for a portable set. There is very little to say regarding the operation of. this set. With the set operating at the high pitched whistle vary the grid leak until the whistle is almost inaudible and then turn the condenser CI. If there is anything in the air it will come in. This set is really simpler to build and operate than a common regenerative set. As to the volume a station 25 miles away comes in so loud that the signals are plainly audible with the phones lying on the table. — Lee H. Bolen, Hamilton, Montana. Simple One-Tube Hook-Up With the hook-up shown I have obtained better reception than any person in my neighborhood. The coil is wound with number 24 dec. wire. The condensers are CONNEU/EY ELECTRIC LABORATORIES 3Q9 Fifth Avenue new YORK CITY METAL Crystals of Quality Trade Mark Reg. U. S. Patent Office. The B-METAL Loud Talking Crystal was the first really standard crystal offered under a reliable "complete satisfaction guarantee," and it sprang into immediate popularity, remaining at present in its third season, the best seller of any standard priced and quality crystal. B-METAL has kept pace with developments and has constantly been improved by the use of purer base materials, scientific treatment, and more care in inspecting and testing. The quality has gone up 100% and the price is still 50 cents. No premiums are offered to sell BMETAL, nor can Genuine B-METAL Crystals be bought at less than standard price. If your dealer cannot supply you, send to us. We will send one only to anyone writing us and agreeing to pay promptly jf satisfied. we want every Radio owner to know what B-METAL Crystals are. Write today. . Dealers and Jobbers please gel our proposition mZlMNlvTMMmXBm DETROIT. MICHIGAN (iD (§jj) # (jfij) «i< m is! i 45 TO 67 VOLTS. 11-plates each. Both are quite important in this hook-up, I have an aerial 30 feet above the ground and have heard from 35 to 40 distant stations. — Harold Beardslee, St. Louis, Mo. A speck of dust is sufficient to cause the whole set to stop working if it happens to get in the right place. D^ tie* PHILADELPHIA TO LONDON Quoting from front page of Philadelphia Inquirer, December 26th, 1923: "At about 10:57 o'clock Mr. tuned in 2LO (London)." UNCLE SAM *SS^^ TUNING COILS Brings in Stations You Never Heard Before Ask your dealer or send self -addressed stamped envelope for wiring diagrams and panel layouts of circuits in which the wonderful Uncle Sam Coil can be used. Price $5.50 UNCLE SAM ELECTRIC CO. 217 E. 6th St. PLAIN FIELD, N. J. Panel Mounting Shaft For a Spider Web Coil Procure a brass rod A 7% inches long and 3/16 inch in diameter and bend it at a point 4 inches from one end to an ang-le of 90 degrees, as shown in the illustration. Flatten the short end to about 1/16-inch thick and drill a 3/16-inch hole through the flattened part. Procure a collar with a set screw B, SSPJDEI? WEB COIL N a spring C and a brass bushing D. Drill a M,-inch hole in the panel and insert the bushing, put on the dial, tighten the tension spring and it is ready for use. It is best to mount the stator coil on the end of the cabinet with the tickler coil next to it. I have a set in which I use two of these coils, and it may be used on three coils as well. — George Sherwood, St. Paul, Minn. •Dealers Need This 200% Profit The new FAHNESTOCK Display Case Will stimulate your sales of Fahnestock Badio Products. 14 of the most popular styles and sizes are included. Shows the purchaser instantly the correct piece for his set. A constant invitation to buy Fahnestock Products. Dealers are offered 200% profit on each case, an unusual offer on standard merchandise. Price to Dealer $17.50 West of Mississippi 18.50 Transportation prepaid when money order or check accompanies order. Subsequent orders at regular price of $20.00. Contents Retail for $51.50 Refills will be supplied at the regular 100 lot prices, shown in catalogue, which comes with case, less discount shown on enclosed sheet. Send cheel! or money order, today. FAHNESTOCK ELEC. CO. LONG ISI.AND CITY NEW YORK #rumi£r It will pay you to keep your eye on PREMIER this season. There will be some new surprises that will make you "Sit up and take notice." PREMIER PARTS will be verv much heard from and talked about so keep "tuned in." Send for latest Bulletin No. 94! Ask your dealer fremitr Jjteririr famp&ny 3810 Ravenswood Ave. CHICAGO