Radio Digest (Apr 1925-Jan 1926)

20 RADIO DIGES T— Illustrated June 13, 1925 TUNED R.F. ADVANCES (Continued from page IS) Such a method is and would be quite satisfactory in addition to its effectiveness were it not for the fact that a method such as this requires an unusual amount of space and for the more pertinent reason that one of their fields would Pig-are 16 also be at rigrht angles to its condenser control, a bad practice. Thus in order to keep all fields in parallel with their separate condenser plates and to conserve space, the angle mounting scheme has cotoe to the fore as being more expedient. Correct Parallel Angles Do not confuse these critical degrees as other than divisions of a circle comprising 360 degrees in place of assuming Figure 17 them as . degrees or divisions upon your tuning dials. Most of the errors occur because the shape, diameter and length of the winding is not considered, or the coil spacing is not taken into account. The experimental builder usually considers the total length of the coil support rather than the winding on and its diameter. Figures 17 and TS picture two examples '///////;. Mm. '■/'. /J'.f'.S/'/ j m I I % I ■/// If J I 1 ■<///, The title y0^j^ tf Radio xtf?///, ■nV-nn^x^n^xS>S^xnxv^nvsn5\ reported. /nn*vv^ YV///////////////////.'//.'//////oy//^>^. ^>r/////, Distance on the phones — with certainty and regularity — on the Crosley one-tube 50. The radio which told the world that the MacMillan Xorth Pole expedition was safe and sound. The radio that kept communication open to Leonard Weeks at Minot, N. D., when all other receivers failed. There is nothing better than the Crosley 50 for the radio beginner. There is nothing to excel it in value; unless it be the larger Crosley sets. Stations always come In at the same plare. For sale by good dealers everywhere. Other modfls priced from the two tube 61, at $18.50, to the Trirdyn Special with sloping panel, at $65. All Crosley Radios are licensed under Armstrong Regenerative U. S. Patent Xo. 1.113.149. Prices quoted are without accessories. Prices Weslof Rockies— Add 10% Write for Complete Catalog The Crosley Radio Corporation Powel Crosley, Jr., Preildent 6492 Sassafras St. Cincinnati. Ohio Crosley owns and operates Broadcasting Station H'LIV £ " : ..■ ....■■:■',...-■..■.■■ — ."■ ML i i k '///■ • /■■/. ■■:■■■ v///„ m II i ■<V' ■y. , of unlike angles, upon the same center to center spacing, one being of the standard 3 u -inch coil mounting, 3 inchs in diameter with a winding 3 inches long, while the other is of exactly the same length of winding, but has a diameter of 21i inches and a total coil mounting length of 4% inches. Each respective pair are mounted at the correct angle in order to secure zero magnetic coupling while the fields cross at right angles yet the angle of mounting is different in each case. Now check back on your tuned frequency receiver and be certain your angles are correct. My fourth article appearing next week will visualize the wheatstone bridge theory and its application to Radio cir Fignre 18 cuits in order that you may not only be conversant with this principle which will make history in ratio this fall, but also have an understanding of the fundamental governing their design and a working knowledge for your own experimentation as this principle and its application to Radio offers easily literally hundreds of opportunities for invention in its manifold ramifications. (TO BE CONTINUED) A. B. C. RADIO COURSE (Continued from page 191 electrical energy, just as coal is a fuel, the chemical energy of which is converted into heat by means of oxygen, a furnace, water and a boiler. When the hydrogen, H2. gives up its positive charge to the positive plate, it is very likels' to cling to the plate and form a layer of hydrogen around it. This accumulation of hydrogen gas on the posi The "Goode" Two-o-One A Le Ton d'srgent Postpaid QUARTER AMPERE AMPLIFIER DETECTOR RADIO TUBE GUARANTEED SATISFACTORY All "GOODE" Tubes Sold Direct to the Consumer — No Dealer Profits $1.89 5.00 ONE — "Goode" DetectorAmplifier THREE — "Goode" Detector-Amplifiers (All posUfe prepaid) The "Goode" Two-o-One A Tube amplifies or detects. It Is a quarter ampere. Are folti, standard base silvered tube. Send express or postal money order — New York draft — or personal check to — The Goode Tube Corporation Incorporated Owensboro (Dept. A) Kentucky tive plate is called polarization. Since hydrogen gas is a very poor conductor of electricity, the presence of the hydrogen causes a marked increase in the internal resistance of the cell. As a result of this increase in internal resistance a larger part of the electrical pressure produced by the chemical action must be used in the cell itself in overcoming the internal resistance, which results in a smaller part of the electrical pressure being available at the terminals of the cell to act upon the external circuit. The electrical pressure due to the chemical action is also reduced because there is an electrical pressure set up between the hydrogen and the positive plate, which acts in the opposite direction to the electrical pressure set up between the zinc and the sulphuric acid. Hence, the electrical pressure between the terminals of a cell decreases in value, for the two reasons given above, as the cell becomes polarized. In order to overcome the polarization of the cell, some means must be provided to clear the positive plate of the hydrogen bubbles. The most common method is to introduce into the electrolyte some chemical called a depolarizer, which has a surplus of oxygen in it. This oxygen then, very easily unites with the hydrogen and forms water. H^O. If the depolarizer is one which acts quickly and gets rid of the hydrogen bubbles as fast as they are formed on the positive plate, the cell may be run continuously without polarizing, and as a result without much decrease in the electrical pressure between the terminals of the cell. A cell of this kind is called a closed circuit cell. If the depolarizer acts more slowly and the hydrogen gradually gathers on the positive plate when the cell is delivering a current the cell can be used only intermittently, in order to allow the depolarizer to combine with the hydrogen and clear the positive plate. A cell of this kind is called an open circuit cell. The ordinary dry cell is an open circuit cell, and if run continuously the effects of polarization are very noticeable. On the other hand if a closed circuit cell is allowed to stand on open circuit, the depolarizer usually ruins the cell by causing certain chemical changes in the electrolyte. For these reasons, it is essential that you use the different types of cells in the circuits for which they are intended. It is not always possible to have the plates composed of pure metals and when there are impurities present, especially in the negative plate, there will be a chemical action which is spoken of as local action, take place which will result in a wasting away of the negative plate and no electrical pressure will be produced between the terminals of the cell as a result of the action. If a cell is capable of producing a current directly from the consumption of some metal such as zinc, it is called a primary cell. If, however, and electric current must be first sent through the cell to bring it to such a condition chemically that it is capable of producing a current, it is called a secondary, or storage cell. The fundamental distinction between a primary and a secondary, or storage cell is that, with the later type the chemical changes are reversible, while with the former type this is not practical even when possible. There are numerous forms of primary batteries, but the one that is used at the present time more than any other is the dry cell. Certain cells are spoken of as dry cells because the electrolyte is held in an absorbent material which will allow the cell to be used in any position. The cell is, however, not dry. Ordinarily the container for the cell is made from a thin sheet of zinc which serves as one plate of the cell. The electrolyte consists of a solution of ammonium chloride, commonly called salammoniac, and zinc chloride. The electrolyte is held partly by an absorbent material that lines the zinc container and partly by a mixture composed principally of ground carbon and manganese dioxide (Continued on page 22) Now! SUB-PANEL MOUNTING TYPE They permit a neater assembly, shortening of leads and concealing' of wiring— as in factory built sets. Same ratiossame prices — as standard type Thordarsons. Order direct if dealer cannot snpply. Makers of sets costing up to hundreds of dollars each are mighty particular to use only the best transformers. Follow the lead of the leaders — build or replace with Thordarsons. For the "Best" 45,000 Cycle SuperHeterodyne, "RADIO" and other leading publications recommend in highest terms the Thordarson 2-1 ratio transformers. Take no others I Unconditionally Guaranteed RDAR Sup** AMPLIFYING TRANSFORMERS Standard on the mtgoritt} of quality sets "Write for free hook-up bulletins. THORDARSON ELECTRIC MANUFACTURING CO. Transformer specialists since 189S WORLD'S OLDEST AND LARGEST EXCLUSIVE TRANSFORMER MAKERS Chicago. U.S.A.—— Thordarson "Super" Audio Frequency Transformers are to be had in three ratios: 2-1, $5; 3%-l, $4; 6-1, $4.50. Thordarson Power Amplifying Transformers are $13 the pair. Thordarson Interstage Power Amplifying Transformer, $8. THE THREE, BLESSINGS OF RADIO Can Only Be*Obtained WITH A KANE ANTENNAE BLESSING No. 1 The Kane Antennae absolutely eliminates all power noises. BLESSING No. 2 The Kane Antennae cuts re-radiating squeals at least 50 per cent. BLESSING No. 3 The Kane Antennae will reduce Static at least 50 per cent. Now that Old Man Static is beginning to get in his usual summer work of ruining radio reception with his discordant crackling noises, wouldn't you like to rap his fingers and make him let up a whole lot? Static and Re-radiating squeals both cut 50 per cent — Power Interference absolutely cut out — Figure it out for yourself! Can you afford to be without a Kane Antennae? Then why not order one today? "I had no idea that an aerial could make so much difference in a set,'* writes Mr. George C. Pratt, Secretary of the Beaver Cove Lumber and Pulp Co.. Ltd., Vancouver, B. C. "I will be glad to recommend this aerial to anyone in this vicinity as the best on the martlet, and I have tried every, kind I have heard of." Mr. Pratt also states. AND WHAT ABOUT OLD MAN STATIC? Gentlemen: Vancouver, B. C, May 16, 192r>. I have received the Kane Antennae shipped a couple of weeks ago, and have installed same as per your instructions. I had no idea than an aerial could make so much difference in a set, as I thought 1 was Betting excellent reception with the old single aerial, but there is no comparison in the present reception of the set with the new aerial, as with the old one. I have been informed by several radio friends of mine that the static has been so bad for the past ten days that they were unable to tune in any exeept local stations, but outside of a very few instances I have not heard static since your Antennae was installed. The antennae is about -15 feet from the ground with the lead-in facing southeast. The counterpoise is about 25 feet beneath the antenna. I have had no difficulty in tuning in KDKA. WCCO, WOC, WEBH, in fart I am getting all the distance I want with very little interference. I will be glad to recommend this aerial to anyone in this vicinity as the best on the market, and I have tried every kind I have ever heard of. Yours very truly. Gee. C. Pratt. ARE YOU GETTING ALL THE DISTANCE YOU 'WANT? We will sell you working drawing with instructions for erecting this wonderful Antennae for a dollar bill. If after locking over the drawing you decide you would rather havo 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-Hets $ 6.50 The Regular Kane Antennae for all other sets that use a ground connection 13.00 Working Drawing's with Instructions for Erecting1, $1.00 (STAMPS NOT ACCEPTED) Postpaid to any part of the United States, or sent C. 0. D. when 25% of purchase price accompanies order. Canadian Orders filled by The Kane Antennae Company of Canada. 1220 Seymour Street, Vancouver. B. C "HEAR AS YOU HAVE NEVER HEARD BEFORE" THE KANE ANTENNAE COMPANY, (D«Pt.c), Hoquiam, Washington The enormous volume of business we are now doing has compelled us to purchase our own factory with over half an acre of floor space In Hoquiam (Indian name, meaning "Hungry for Wood") the most Westerly City in the United States.