Radio age (Jan-Dec 1925)

34 RADIO AGE for June, 1925 The Magazine of the Hour Radio Age Institute Manufacturers' Testing Service A/f EMBERS of the staff of RADIO AGE will be pleased to test devices ■'■»■'■ and materials for radio manufacturers with the object of determining their efficiency and worth. All apparatus which meets with the approval of various tests imposed by members of the technical staff of RADIO AGE will be awarded our endorsement, and the seal shown to the right will be furnished free of charge. Materials for testing should be sent to RADIO AGE INSTITUTE 504 N. Dearborn Street, Chicago, 111. DEVICES displaying this seal have been tested and approved by the RADIO AGE INSTITUTE. Apparatus illust r a t e d and described below has successfully passed our tests for June, 1925. Test No. 59. THOROLA Low Loss D o u g h n ut Coils. Manufactured and submitted by the Reichmann Company of I Chicago. These coils embody a new type of winding, which p ro d u c e s a very good ratio of resistence to inductance, which is a true measure of coil efficiency. This winding minimizes energy losses in inductance. Due to a unique and scientific shape employed in this coil, called "doughnut" or toroidal, selective operation is easily secured, and there is no undesirable "pick-up" as in open coils. The coil submitted for tests was found to satisfactory pass the tests and requirements of the RADIO AGE institute over the period in which it was used in our laboratory. Test No. 60. The UNIVERSAL AERIAL MAST FITTINGS, manufactured and submitted by the Universal Mast Company of 3215 Montrose ave., Chicago, 111. These fittings come complete in one box and are a welcome surcease from the bother of making new aerial supports every time a fan wishes to erect a new aerial, after moving, etc. The material for masts using these fittings should preferably be 2 x 2 in. cypress or yellow pine. The bases can be attached to such masts very easily. The guy attachment, also contained in the kit, is fastened one-third up from the bottom of the mast. The ends of the base plates may be flattened down to give additional bearing surface. These fittings were tested both on wooden and on apartment building roofs, and were found practicable for both, besides being unusually firm against the wear and tear of wind, rain. etc. Satisfactorily passed the tests and requirements of the RADIO AGE Institute. Test No. 61. RADION BUILT IN LOUD SPEAKER HORN, Manufactured and submitted by the American Hard Rubber Co. of II Mercer St., New York City. A unique horn barely a foot high, which can be built in a portable or other receiving set, and a standard headphone unit attached to its base. May also be used for a loud speaker in a hotel room, etc., where intense volume is not desired. Instead clear and sweet tone is produced. The horn is made of RADION, the American Hard Rubber Company's material, also used for radio panels, etc. The horn sent to this magazine was tested both for portable and built-in sets, and in every way satisfactorily passed the tests and requirements of the RADIO AGE Institute. Test No. 62. SONORA RADIO SPEAKER, with concealed horn. Submitted by the manufacturers. The Sonora Phonograph Company of New York. This loud speaker, besides being of unusually attractive design, produces very clear and deep tone; in fact, the tone is almost identical with that produced by high class phonograph, having been designed after that style and with that end in view. A patented all-wood horn, the same as used in the Sonora Phonograph, and a Sonora tone arm and radio reproducer, are encased in the beautiful cabinet, which blends with the furniture of any home. The speaker is small enough to be placed on a table, mantel or on the radio set itself. Satisfactorily passed the tests and requirements of the RAD'O AGE Institute. Test No. 63. MICA FIXED CONDENSER, manufactured and submitted by the Sangamo Electric Company of Springfield, 111., makers of electric meters. This condenser is guaranteed accurate within 10 per cent of the marked capacity and to sustain its original accuracy under all conditions. Their accuracy is likewise not affected by the heat or acid used in soldering. These condensers show up best in reflex circuits because of their accuracy. The condenser is sealed in a smooth brown bakelite case, making it impervious to atmospheric changes. Also presents a neat appearance. Satisfactorily passed the tests and requirements of the RADIO AGE Institute. Test No. 64. RADIO PLUG submitted by Pacent Electric Co., Inc., 91 Seventh Ave., New York City, N. Y. A plug for connecting either a loud speaker or a headset to the output jack of any receiving set. It is well made, having firm grip for the telephone or loudspeaker tips. Tested and approved by RADIO AGE Institute. Test No. 65. Metallized Grid Leak, submitted bv Durham and Co.. Inc., 1936 Market St., Philadelphia, Pa. Consists briefly of a glass rod of small and uniform diameter, coated with a metallized high resistance material by means of a high temperature and gas process. Resistance then impregnated in a nonhydroscopic insulating fluid, and after an aging period, is cut and assembled in the air tight cartridge The end caps are soldered to the resistance unit instead of using low melting alloy. Tested and approved by RADIO AGE Institute. Test No. 66. SILVER "'TWO-TENS" and "TWO-ELEVENS." Long wave transformers. Supplied in sets of 2 or 3 2 1 0s (iron core interstage and one 211, (filter for input or output) with identical peaks and separate curves. The feature of these transformers lies in the fact that the makers plot the curve in their own laboratory and record them directly on a tag attached to each transformer before it is placed on sale. Tests to determine the accuracy of these charted and matched transformers were conducted in this magazine's laboratory and in every instance the tag attached to each transformer was found to have the correct curve. Manufactured and submitted by Silver-Marshall, Inc., 105 S. Wabash Ave., Chicago. Satisfactorily passed the tests and requirements of the RADIO AGE Institute. Test No. 67. The Remo RADIO TUBE REACTIVATOR. Manufactured by the Remo Corporation of Meriden, Connecticut. An instrument selling at a reasonable price for reviving weak or old tubes and bringing them back in volume as good or better than new ones. Designed for standard amplifying tubes of the UV201A type or UV199 tubes. Three UV201A or two UV199 tubes can be accommodated at once. Detector tubes of the UV200 or WD12 type cannct be revived. The Remo Reactivator is used only with regular 1 10 volt 60 cycle AC current and is furnished with cord and plug. While such a device is comparatively new in the radio field, the Remo Reactivator satisfactorily passed strict tests of the RADIO AGE Institute in the tests for which it was used. Test No. 68. 1926 MODEL NEUTROWOUND RECEIVER. A new principle — incorporated in the Neutrowound Radio Receiving Set — enables the operator to "tune in" near or distant stations, and operate at the highest peak of radiofrequency amplification — at all wave lengths — insuring consistent reception, over very great distances with the maximum selectivity — free from outside interference. The all-metal case not only serves as a sturdy protection for the vital parts of the receiving set, but also acts as an electro-magnetic shielding against outside interference. Howls, noises and distortions are eliminated. Satisfactorily passed the tests and requirements of RADlO AGE Institute. Test No. 69. VALLEY BAT. TERY CLIP. Submitted by the Valley Electric, Company of St. Louis, Mo. This clip is of the conventional type in use for A battery connections, having firm, toothed jaws for gripping the positive or negative posts on batteries. A screw is provided for making firm contact with the wire. Satisfactorily passed the tests and requirements of RADIO AGE Instrtute.