Radio age (Jan-Dec 1926)

RADIO AGE for February, 1926 Carborundum Detector With Stabilizing Device AMONG some of the products of the Carborundum Co., is a stabilizing detector unit, recently released for the j radio trade, which may be used in any crystal detector set or in the reflex type of receivers. The unit, which may be mounted on the panel, electrically controls the resistance of the detector circuit, by varying the potential of a flashlight cell applied to the carborundum crystal; a procedure which will be remembered by old time ship operators, notably those who went to ,sea with the old Marconi receivers with a huge wire potentiometer for altering the bias applied to the crystal. Two advantages noted in the use of changing the resistance are: ability to increase detector resistance to gain selectivity without losing energy transfer from antenna circuit, and to determine the degree of damping of the detector circuit in a reflex receiver, which damping may be made to aid regeneration. The contact on the crystal is permanent, or fixed, while the resistance is the variable factor. Victoreen Intermediate "YTICTOREEN intermediate transform* ers, handled by the George W. Walker Co., have a sharp resonance curve. This resonance feature of the coil permits use of an aperiodic primary, prevents interstage oscillation, makes the set more stable and permits the use of a potentiometer as a volume control. _ Victoreen coils are adjusted to a precision of one-third of one per cent. The wave length used assures less interference by harmonics. The Magazine of the Hour 53 NATIONAL Velvet Vernier DIAL Type B, Variable (Patents Pending) Easily mounted on the any standard type of Positive Control — Easily Mounted YOU control the reduction ratio with this new NATIONAL Type B, Velvet Vernier Dial. And what a difference in the tuning of your set! You'll be astonished. -4 in. shaft of variable condenser. A screw driver is the only tool you need. It has the same velvety smoothness, the same freedom from backlash, the same mechanical drive as the NATIONAL'S famous Type A dial. Write for Bulletin 107 RA NATIONAL CO., Inc. W. A. READY, President 110 Brookline St. Cambridge, Mass. This Aerial Gets Everything But Noise! KANE ANTENNAE COMPANY, DRAY RADIO LABORATORY 6 EAST LAKE ST., CHICAGO Precision Radio Apparatus Tests, December 24, 1925 Gentlemen: As you requested we are enclosing under separate cover a picture of the Kane Antennae you recently installed on the roof of our building, at Lake and State Street, Chicago. As you know, we have never here at the Laboratory been able to get clear reception from distant stations. As soon as we turned on enough power to bring in the DX we of course picked up the electric sign noises, the elevated noises, the telegraph office next door, the street cars, the elevators, etc. Loop sets with their strong pick-Up of local noises were particularly bad. For the la->t couple of months we have been getting letters from our dealers telling us that if we could only figure out some wny to install radio sets near power noises with xune scheme of Antennae that would bring in the distant station with ! ess of the local noises, that they could sell more sets in difficult place-* "here all make of radio-; hud proved too noisy for satisfaction. In many cases these dealers could not give decent demonstrations in their own stores. Finally we heard from Henry Stah I and Son, our dealer at Elkhart, Illinois, that they had eliminated the interurban and power line noi.-es at their store by the use of a Kane Antennae. This was what led us to a-k you to show what you could do for us at the Laboratory. Last night when we tested out your eighty foot transposed antennae and counterpoise, we were very much surprised. We had distant reception of very good quality. We checked back by using the usual type of ground and the ratio of power noises to DQUsio increased several hundred per cent, rendering the reception absolutely unsatisfactory. Then we would switch back again and get very excellent reception. We are enclosing a check in payment of your invoice. We are going to tell all of our dealers about our experience. After all the perfect schemes that we have wasted time in trying, we are glad to grant you the permission of publishing this letter if you care to. Very truly yours, DRAY RADIO LABORATORY. By W. R. Dray. The KANE ANTENNAE entirely eliminates all power noises such as leaky Transformer*. Generators, Motor hums. Delco Plants, etc. Power noises cause more trouble than all other forms of Radio interference. Get rid of them \" i >\Y by ordering a KANE ANTENNAE. Get Facts NOW About The Kane Antennae We will send you working drawing wit n in-irn-'unn for erecting this wonderful Antennae for a dollar bill (a check will do). If, after looking over the drawing, you decide you would rather have a factory-built Antennae than build one yourself, we will take back the drawing and allow you full purchase price on an order for an Antennae. The Special Kane Antennae for Radiola Super-Hefa $10.00 The Regular Kane Antennae for all other sets that use a ground connection 20.00 Working drawing with instructions for erecting 1.00 (Stamps not accepted) Postpaid to any part of the United States or sent C. O. D. when 25 per cent of price accompanies order. THE KANE ANTENNAE CO. Dept. 820B, 3343 W. Monroe St. Chicago, IU. Send 25c for Booklet Telling How to Build the Kj-iammarlund ) oDeris Hammarlund-Roberts, 1182 Bway, N. Y. C. NO MORE LOOSE CONNECTIONS X-L PUSH POSTS A binding post that really does excel, looks, action, service, and conTenlence. Push it down — insert wire — cannot jar loose from vibration. No screwing or danger of shearing off wires. Furnished attractively plated with soldering lug and necessary markings. Price Eath.. — 15 Centi X-L RADIO LABORATORIES, 2424 Lincoln Avenue N. SendNoMoney Jnst pay postman after album and FREE stamps arrive. We prepay postage if you prefer to pay with order. Satis ^*" faction truaranteed MONEY REFUNDED if not DELIGHTED. Send order todayNOW. Postal will do. IDEAL CO., Dept. 2022, 366 Wrigley Blag., Chicago Use the Log-a-Wave Chart Tell them you read it in Radio Age