Radio Broadcast (Nov 1926-Apr 1927)

3-24 RADIO BROADCAST ADVERTISER USE THESE COILS AND IMPROVE ANY RADIO RECEIVER! CO ISITIVE INDUCTANCE UNITS Tuned Radio Frequency Kit £12.00 The Aero Coil Tuned Radio Frequency Kit illustrated above will positively improve the performance of any receiver. Patented Aero Coil construction eliminates radio frequency losses and brings tremendous improvement in volume, tone and selectivity. Kit consists of three matched units. The antenna coupler has variable primary. Uses .00035 condenser. 8 page color circuit, layout and instruction sheet for building the supersensitive 5 tube Aero-Dyne receiver packed FREE with each kit. Extra copies, 75c each. Instructions include insert showing how to wire up for a power tube if desired. Low Wave Tuner Kit #12.50 Completely interchangeable. Adapted by experts and amateurs. Range 15 to 130 meters. Inclu des three coils and base mounting, covering U. S. bands, 20, 40 and 80 meters. You can increase the range of this short wave tuner by securing coils No. 4 and 5. Combined range of 15 to 550 meters. Both interchangeable coils fit same base supplied with short wave kit and use the same condensers. Coil No. 4, price $4.00; Coil No. 5 price $4.00. Get these coils from your nearest dealer. If he should be out of stock order direct from the factory AERO PRODUCTS, Inc. Dept. 109 + 1772 Wilson Ave. Chicago, III. Famous Now Sold on Easu Terms IDial 6 Tube ay Complete With All Accessories Get Agents Price— Save SO",; Great nownl Now owd a famous Mnrwood at the WOrld'nlOweat price for real quality — tind pay on cney tormB. Tin only Ka.lio k..I<] ilirret on cnay torniB— proof Ihiit Uii-Murwo-.d MUST be a womler. A year ahead will. -1 \,w. pxrhiHivo improvements SuperKrl.-.-fivilv. IW.-r-Tube Vnlumo. New KaHV-Tm.iiu: l-rinripli New Ti.no Quality. Have half— uuJ eel u Radio that can't bo bent at ANY prim?. 30 Days Free Trial _ trust you. Pr I I ho lout bu; MARWOOD RADIO CORPORATION 1747mi; Morse Avenue, Chicago, III the storage battery. General Lead Batteries Company. 36. Charging A and B Batteries — Various ways of connecting up batteries for charging purposes. Westinghouse Union Battery Company. 37. Choosing the Right Radio Battery — Advice on what dry cell battery to use; their application to radio, with wiring diagrams. National Carbon Company. Miscellaneous 38. Log Sheet — A list of broadcasting stations with columns for marking down dial settings. U. S. L. Radio, Incorporated. 39. Behind the Scenes in a Broadcasting Station — Operation in general, and specific facts about wkrc. Kodel Radio Corporation. 40. Static — A brief discussion of the disturbances which may cause trouble in a receiver. Sun Manufacturing Company. 41. Baby Radio Transmitter of qxh-cje k — Description and circuit diagrams of dry-cell operated transmitter. Burgess Battery Company. 42. Arctic Radio Equipment — Description and circuit details of short-wave receiver and transmitter used in Arctic exploration. Burgess Battery Company. 43. Short-Wave Receiver of 9XH-9EK — Complete directions for assembly and operation of the receiver. Burgess Battery Company. 44. Aluminum for Radio — A booklet containing much radio information with hook-ups of basic circuits, with inductance-capacity tables and other pertinent data. Aluminum Company of America. 45. Shielding — A discussion on the application of shielding in radio circuits with special data on aluminum shields. Aluminum Company of America. 46. Audio Frequency Chokes — A pamph let showing positions in the circuit where audio frequency chokes may be used. Samson Electric Company. 47. Radio Frequency Chokes — Circuit diagrams illustrating the use of chokes to keep out radio frequency currents from definite points. Samson Electric Company. 48. Transformer and Impedance Data — Tables giving the mechanical and electrical characteristics of transformers and impedances, together with a short description of their use in the circuit. Samson Electric Company. USE THIS COUPON Radio Broadcast Service Department Radio Broadcast, Garden City, New York. Please send me (at no expense) the following booklets indicated by numbers in the published list Name Address (Number) (Street) (City) (Slate) ORDER BY NUMBER ONLY This coupon must accompany every order. RB 127 Physics for the Radio Man PRACTICAL PHYSICS. By Black and Davis. Published by the Macmillan Co. Revised edition, 1925. 572 pages, including supplementary pamphlet, 1926, on "Radio Broadcasting." $80 illustrations. Price, $1.68. THE original meaning of "physics" was "the study of natural philosophy, the science of the principles operative in inorganic nature." The lever, the arch, the windlass, the pulley, and the flow of liquids were the foundations of a branch of human knowledge which to-day has acquired endless ramifications. To-day we cannot think of physics either as "natural philosophy" or as a thing so abstract as "the principles operative in inorganic nature." It is a study of principles, the operation of which surround: us at every moment. The authors of "Practical Physics" have been diligent in bringing home to their readers the practical application of physics in the things of daily life. They have not contented themselves with statements of laws, formulas, and principles. There is hardly a page which does not illustrate some familiar device in general use as examples of the principles expounded in the text. For example, by turning only a few pages, we found clear-cut diagrams of a vacuum cleaner, phonograph, door check, carbon transmitter, automobile speedometer, dry cell and voltmeter, water tap, lawn sprinkler, electric iron, and a steam radiator vent. By this means, its writers have made their comprehensive volume interesting reading, a quality usually lacking in reference books and school texts. I he problem of writing a physics text book is largely one of elimination. To attain conciseness without undue length, yet completeness •jf Examined and approved by Radio Broadcast -At sufficient to be useful, ease of reference, and ' questions and problems for study purposes, in a mere 572 pages, is indeed no small problem. Good arrangement has contributed liberally in making the attainment of these objectives possible. Every section is numbered and headed in bold face for easy reference; questions and problems are distributed in convenient grouping, not only at the end of each of the twenty-four chapters but at each logical point throughout the text, permitting of easy assignment for study; at the end of each chapter is a summary expounding crisply the laws, principles, and conclusions of the entire chapter. To the radio enthusiast, ease of reference is of great importance, for he consults a physics book solely to refresh his mind on some particular fact or principle. He finds a knowledge of many branches of physics enters into his radio problems. A vernier dial is not a radio device nearly so much as it is a mechanical contrivance: the physics of sound contributes its share to attaining good tonal quality; a knowledge of electrical engineering is essential when the storage battery, power-supply device, fuses, chargers, power transformers, and numerous other parts of radio equipment are being considered. A textbook on physics is indeed no intruder in the radio enthusiast's library. In fact, more often than not, the radio devotee is quite unfamiliar with the principles outlined in Chapter XIII, dealing with Magnetism; XIV, Static Electricity; XV, Electric Currents (i. e . units, resistance, its application to series and parallel circuits, battery connections, and numerous practical points in constant use about the radio laboratory); XVI, Effects of Electric Current (describing relations of electricity and magnetism, bells, telegraphs, meters, fuses, circuit breakers, lamps, storage batteries, arcs, etc.);