Radio Digest (July 1924-Apr 1925)

16 RADIO DIGES T— Illustrated July 19, 1924 THIRTY-MINUTE A-B-C (Continued from page 13) Figure 167 shows a popular type of tuned circuit. Another popular type is indicated in Figure 16S, employing an untuned aerial circuit. Probably the circuits of this general kind in use today are a large portion of all the sets in the United States. The form shown in Figure 168A re-radiates, as is typical of all such circuits. Figure 169 shows another form of such a circuit. One way to stop re-radiation is to use loose coupling between the circuits, as shown by figure 170. A sensitive capacity coupled circuit is pictured by Figure 171, and a variation of this type is Shown by Figure 172. Circuits with Crystal Detector Added One way to add a crystal detector of tlie fixed type is shown in Figure 173, and ether circuits utilizing the amplifying ability of one tube are shown in Figures 17 1, 175, 176. Figure 174 also illustrates a well known way to neutralize the tube capacity between the filament and grid of a vacuum tube. A neutralizing condenser of small size is connected to an opposing coil so that the tendency of the tube to self oscillate is stopped. Neutralizing Circuits The neutralizing circuit can be in the plate circuit as indicated by Figure 175. Figure 176 indicates how tuned feedback can be employed after the tube capacity has been neutralized. The output of such circuits can go to additional stages when desired. (Reflex combinations, link circuits, super one-tube circuits and possible one-tube circuits will continue next week. — Editor's Note.) Keep all Radio antennas and wiring away from electric light and power wires. HETERODYNE Pfanstiehl Oscillator $600 Postpaid or at your dealers It corrects the usual cause of failure by adjusting the strength of the oscillations to that of the incoming signal. Pfanstiehl Radio Service Co. Highland Park, 111. Chicago: 1001 W. Washington St. Haymarket 8010 DISTANCE! That's what every Radio fan strives for, and the thrill of getting a station thousands of miles away is worth all the time and trouble it takes to build your set properly — And to get that Distance choose your panel wisely — it must be of the best. JHAEK RADIO PANELS (all standard sizes) insure the minimum in surfaceleakage and power loss, and the maximum in volume. They can be bought at all the better Radio stores at — 25 to 50 % Less than any other standard panel Drilled correctly — with a sharp drill and slight pressure — they are unsurpassed, like all the other "Sote" products introduced by THE PANTASOTE CO., Inc. JOBBERS AND DEALERS Write for our interesting proposition. M. M. FLERON & SON, Inc. Exclusive Sales Agents for Electrasote Radio Panels OPERATION TROUBLE (Continued from page 8) the corners, turn the panel back and examine every wire carefully to see that there are no broken wires. Do not forget that your results will very largely depend on your aerial and ground connections. Try and secure the very best of each that you possibly can under the circumstances. Do not think that just because the rheostat lights the tube that you turn it on just as you would an electric light. Do not turn it on too far, because it will paralyze your tubes, and you will get no signal at all. You will quickly find out just where the proper point is. After the aerial and ground wires have been used sometime, the wires, themselves, may break inside of the insulation. Test this by running it through your finger and thumb to see if you can locate it. It is a good plan to try changing the tubes around the various sockets. Sometimes'a tube will work better in one position in the circuit than in another. sS\.""""..~ Broadcasting from Atlantic Coast, Mexico, Hawaii, Canada and Cuba heard in California by users of CROSS COUNTRY CIRCUIT. Range due to simplicity of set and only one tuning control. Easily and cheaply built by any novice. Dry cell tubes may be used. AH instructions, blue print panel layout, assembly Photo, etc. Postpaid 25c. Stamps accepted. VESCO RADIO CO. BX D-117 OAKIAWD, CAL. MlfHb Crystals of Quality Trade Mark Reg. UTS. 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 if satisfied. We want every Radio owner to know what B-METAL Crystals are. Write today. Dealers and Jobbers please get our proposition iM^m^T^mmmmm 14 "if I. 52& WOODWARD AVENUE PETR0AT.Mi€ai6AN Trenton New Jersey To Each Purchaser World Battery A 24Volt ' ^"Storage Batterypositivelygrlven ' FREE with each purchase of a WORLD "A" Storage Battery. The WORLD Battery is famous for its guaranteed quality and service. Backed by yeara of Successful Manufacture and Thousands of Satisfied Users. You save 60%. j Prices That Save and Satisfy Auto Batteries Radio Batteries 6-Volt, 1 1 Plate $12.25 GVolt, 80 Amps. Sio.oo G-Volt 13 Plat A 1A?« 6-Volt, 100 Amps. 12. SO .!. J' »«.ZS 6-Volt. 120 Amps. 14.50 12-Volt. 7 Plate 17.00 6-Volt, 140 Amps. 16.00 Shipment Entrees C. O. D. subject to examination. 0 per cent discount for caah in full with order, 2-Yr. Guarantee Bond in Writing With Each World Storage Battery proves satisfactory World performance. Mall this ad with yoor name and address — wo wlllnhlp battery day order Is received; and (five you your choice of B' ' Storairo Eattery ora handsomenlckle finish Auto Spotllte. FREE. Write TODAY. WORLD BATTERY COMPANY 60 E. Roosevelt Road Dept. L, CHICAGO, ILL. This FREE "B" Storage Battery takes the place of dry cell "B" batterlei. Can be recharged and will last indefinitely. To be sold retail for $6.00. It Ij Lhe only battery of Its kind equipped with nolid rubber case— and Iniuranco avalnst acid and leaksjre. Take advantage of this remarkable Introductory offer NOW. (To those who_prefcr It. we will send FREE a handsome nickel finish Auto Spotllte, instead of the "B" Battery. Be sure to specify which Is wanted.) GIVEN FREE To introduce this new and superior World "B" Storage Battery to the Public Miladys Knitting Needle It may seem a simple suggestion, but in my experiments I have found many uses for the common celluloid knitting needle around the Radio set. They are very inexpensive, from 10 to 15 cents each, and range in size from % to Vi-inch in diameter and as much as 14 inches in length. For cutting down body capacity they are just the thing for the variocoupler and variometer shafts, and for the radiating spokes of a spiderweb cell they are the "berries." By heating them slightly they may be bent to any desired shape. Be careful when heating these needles that you do not hold them near a flame. The best way to do this is to place them in hot water for a short while.' M*any uses may suggest themselves to the experimenter.— Arthur L. Kaser, Mishawaka, Ind. C\ WE REPAIR THE FOLLOWING RADIO TUBES Dealers and Agents write for Special Discount Mail Orders Solicited and Promptly Attended to WD-11, WD-12, Our Specialties WB-11 $2.50 WD-12 2.50 UV-200 2.50 UV-201 2.50 C-300 2.50 C-301 2.50 DV-6 2.50 DV-1 2.50 DV-2 2.50 DV-6A $2.50 TJV-199 2.50 C-299 2.50 UV-201A 2.50 C-301A 2.50 Marconi 2.50 Moorhead 2.50 6 V. Plain Det 2.50 6 V. Plain Amp 2.50 H. & H. RADIO COMPANY P. 0. Box 22-A Clinton Kill Station NEWARK, N. J. a lAURd tube Neutrodyne Receiver You can assemble one in a few hours. For distance, selectivity and loud speaker volume there's nothing better. The FADA 5-tube Neutrodyne outfit No. 167-A contains everything needed — the finest Neutrodyne parts that can be purchased. The FADA "How to Built It" book makes everything as simple as A, B, C. Buy the original FADA No. 167-A in the sealed package, $65.60. F. A. D. ANDREA, INC. 1581 Jerome Ave. New York JJEl J^a d i o =jjpggglp= ^iiiiiKuiinmiiiBiffmW ) TKIJACK TRI-JACK is a dustproof, solderless, super-compact jack with practica-lly zero capacity — the greatest improvement in jacks so far. Solid bakelite! It costs only $1.25. TRI-COIL Radio Frequency Transformer has done wonders in the one tube reflex circuit. Sells for $2. Write for the FREE construction booklet. BROOKLYN METAL STAMPING Corfc n8 Atlantic Ave., Brooklyn, M.Yj . TRK<H TKI? "■■■■■■II IHIHffllfl Loud Speaker Rattles The problem of rattling sounds from a loud speaker is one of the hardest to overcome, especially if a telephone receiver is used for this part. The fact that the noise is produced by the vibration of this diaphragm inside of the receiver is responsible for this, because when the vibrations get too strong the diaphragm will hit the little magnets inside, thus giving an entirely different tone, and one which is usually not pleasing. On the other hand, running the set below its fullest capacity will frequently give an excellent tone from the speaker, simply because the telephone receiver is running at a point nearer its proper point Overcomes Static^ and Re -radiation/ YoQutsideWim orlijf,mwj<ji/m/mJfee Why pay $10.00 or more to have an aerial spoil the appearance of your home ? Antenella eliminates all unsightly wiring, lightning arresters, etc., and precludes the possibility of dangerous grounding on a power line. It also stops "canary bird" reradiation from nearby oscillating sets interfering. ANTENELLA is not only a real distance getter, but also overcomes troublesome static. At your Dealer, otherwise send purchase price and you will be supplied postpaid. for Circular A-40 § SS8adio\ Gt i reshmc.nfo.lncJ Condenser Woc/ucts _ 106 Seventh Ave., New York ave at Modell's Some of Our Many Bargains LOOP AERIAL D76. Can be assembled by anyone in five minutes; all wood parts, wire and binding posts included, complete, 69c RADIO SOLDERING IRON Indispensable for the man who builds his own seta D 109 $ 1 .95 DI33 — Soldering Paste, tube 25 PLATE CIRCIUT "B" BATTERIES D80— 22V2 Volt Small $1.15 D8I— 22V2 Volt Medium 1.45 D82— 22 V2 Volt Large 1.95 ^ The highest grade of PfPiwSaM battery made a prices JlllllllllIllIilBiilB lower than they ever ill!!!^^» were sold before. D83— 45 Volt Medium 1.95 D84— 45 Volt Large 2.50 D85 — 45 Volt Extra Large 3.50 D86— 360 Hour 1% Volt Twin Double Duty "A" Battery '. 75 WOOD CABINETS Highest grade Mahogany finish Cabinets. Hinged top. These cabinets are being sold at less than one-half regular value. D57 — Wood Cabinet; panel size 7"xl0", eaoh....$2.50 D58 — Wood Cabinet; panel size 7"xl2" 2.75 D59 — Wood Cabinet; panel size 7"xl4" 3.00 D60— Wood Cabinet; panel size 7"xlS" 3.50 D6I — Wood Cabinet; nanel size 7"x21" 3.75 D62 — Wood Cabinet; panel size 7"x24" 4.00 Baseboards (Mahogany Stained) for use with above cabinets 7xX0 25c 7x14 35c 7x21 45c 7x12 30c 7x18 40c 7x24 50c America's Greatest Radio Retailers * (91 FULTON *7I C0RTLANDT BROOKLYN Cor. Church Near Washington **8I Flatbush Ave. •14 CHURCH ST. 15 Whitehall St. Post Radio Elec. Cor. Cortl. Cor. Stone St. Corp. '*0pen Sat. Ev'os)*»24l W. 42d St. ("Open Ev'g) Bet. 7th & 8th Aves. MAIL ORDER DBFT. 58 Church St. NEW YORK CITY