Radio Broadcast (May-Oct 1926)

442 RADIO BROADCAST ADVERTISER Midget Battery Switch Yasar no.io Efficient Filament Control MANY of the finest factory-made sets are equipped with the Yaxley Midget Battery Switch because of its correct design and superior construction. You, too, will like the positive, easy action of this switch. Never gets out of order. Small in siz;e. Phosphor bronze springs. Pure silver, self-cleaning contacts. One nut mounting in a single 7/16" panel hole. Complete with nameplate, as illustrated. No. 10 — Midget Battery Switch .... 50c Order from your dealer or send his name with your order to YAXLEY MFG. CO. Dept. B, 9 So. Clinton St. * CHICAGO Make any Good Receiver * ^BETTER KE TER Rosin Core Sure ? ■ is Safe and Simple Approved by Radio Engineers . A Genuine Solder Chicago SolderCompany 4222 WrightwoodAve., Chicago, U.S. A. Originators and World's Largest Manufacturers of . Self Fluxing Solder -'ill YOUR DEALER CAN SUPPLY YOU This is a good time to subscribe for RADIO BROADCAST Through your dealer or direct, by the year only $4.00 DOUBLEDAY, PAGE & CO. GARDEN CITY, NEW YORK FAHNESTOCKS NEW SWITCH A new reliable double pole, double throw switch. Binding posts and contacts are made of phosphor bronze. Copper handle with insulated knob. This switch ts made by the makers of the famous Falmcstock Connectors that arc essential for perfect contact FAHNESTOCK ELECTRIC COMPANY LONG ISLAND CITY NEW YORK The Radio Fan's Vade Mecuim HOW RADIO RECEIVERS WORK. By Walter Van B. Roberts, B.S.,E.E.,Ph.D. Published by Doubleday, Page £r Company. 53 pages. $1. THERE has been a demand the last few years for a really comprehensive book dealing with the principles underlying radio reception. The average set builder desires to know the functions of the pieces of apparatus he uses in a receiver, and gradually is inspired to go deeper and deeper into the subject. Most available books either are so elementary as to give one a misconception of the phenomena occuring or else they go into elaborate calculations so that the physical picture of the mechanisms operating are entirely lost. "How Radio Receivers Work," by Walter Van B. Roberts, is a book which fills a long-felt need on the part of many radio experimenters. It gives the elementary electron theory in terms that anyone can grasp, with the help of the mechanical analogies used, and at the same time the ideas conveyed are physically accurate. A few pages are given to alternating current theory in which the function of a coil and a condenser is explained, as well as the circuit which results when inductance and capacity are combined in parallel, to form an oscillatory circuit. This latter circuit is really the foundation upon which any receiver is built, for without it, stations operating on different wavelengths would not be separated, and the word "selectivity" would drop out of our electrical vocabulary. Antenna systems of various types are discussed, and one theory of fading is given which, though interesting, does not seem to explain some of the phenomena which are so readily taken care of by the assumption of the existence of a "Heaviside Layer". Those who have wondered why a vacuum tube can be made to operate as either an amplifier, a detector, or a generator of alternating current, should read the third chapter of Mr. Roberts' book, where the principles of the tube, "The Aladdin's Lamp of Radio" — are discussed in everyday terms. The latter part of the book deals with modern types of receivers, discussing different methods of radio frequency amplification, including the super-heterodyne and super-regenerative principles, as well as regeneration. Audio amplification, under the headings of "Impedance and Resistance Coupling," "Transformer Coupling, " and "Push-Pull Amplification," are discussed. Thus, the important parts of the receiver, the r. f. amplifier, the detector, and the a. f. amplifier, are discussed as separate units, giving the reader the proper prospective on the complete receiver. It should be apparent from this brief resume that here is a book that the experimentally inclined radio fan can well afford to own, one that is a welcome addition to that only too small existing library of authoritative simplified radio texts. Glenn H. Browning. Another Radio Show TO OUR list of radio shows scheduled for the coming season (this list was printed in the August Radio Broadcast), should be added the Omaha Radio Show. This latter will take place during the week of September 6th to 1 1 th, and is being held under the auspices of the Omaha Radio Trade Association, in the Omaha Auditorium. Manager, Chas. A. Franke. Tested and appro"»d h« F./nto Broadcast -A"