Radio Broadcast (May 1927-Apr 1928)

RADIO BROADCAST ADVERTISER 251 Selected for Cooley Rayfoto It is significant that the S-M 220 audio transformer was selected before all others for the Cooley Rayfoto telephoto apparatus. This logical selection bears out past performance — for authority upon authority has made the same selection until 220's are used in more popular receiver designs than any other transformer. Any number of unbiased laboratory tests show the 220 to be supreme in the audio field and the unofficial report of the testing laboratory of the largest telephone manufacturer rates 220's at the top of the list. Remember, if it's real, true tone quality you want, you can pay out ten or twelve dollars for an audio transformer but you can't possibly get a better transformer than S-M 220's at $8.00 each — for none better have ever been made! SILVER-MARSHALL, Inc. 838-B West Jackson Blvd. Chicago, III. Send for Great Book Compiled exclusively for dealers in radio sets, radio parts, and for set builders. An Amazing Catalog containing the newest things in the world of radio. Unbeatable values in Radio Parts, Kits and Supplies of National Fame. A complete array of Cabinets and consoles, in all latest styles, finishes and popular sizes at Unmatched Prices. The high quality of our products eliminates loss. Large stocks offer you large selection. Our speedy shipments insure your customer's good will and bigger profits for you. Silver Marshall Unipac in stock — all models and types. Fully described and priced in our catalog on page 64. Liberal discounts to the trade. Immediate delivery. Short Wave Section Our catalog contains a section devoted to a showing of the highest grade short wave receiving and transmitting apparatus. Also the finest electrical appliances for use in the home. Shure Service means sure profits. You can take orders direct from our illustrated list price catalog. Whatever your radio needs may be, you will find them in our 1928 catalog. Write for a copy TODAY. SHURE RADIO COMPANY 343P West Madison Street, Chicago. Ill, Announcing THE Beach Relay FOR THE Rayfoto Receiver Approved by A. G. Cooley Available Now, Write L. S. BRACH MSg. Corp. 129 Sussex Ave. Newark, N. J. Faithful Service The function of a power resistance is to control voltage and current — accurately — permanently — silently. AEROVOX PYROHMS used with GOOD equipment make a BETTER power unit. AEROVOX PYROHMS are built to last — are used by more than 20 leading power unit manufacturers. — This is conclusive evidence of their reliabilityaccuracy — worthiness. Made in all values of resistance for continuous duty at 20, 40, 100 and 200 watts. y\£R<?WX_ M \ ^^ft^^^^^qjuOt 'Better" ■ \ 70 Washington St., Brooklyn, N. Y. AERO Corona Coil Used in New Cooley "Rayfoto" Of course the new Cooley "Rayfoto" uses an AERO Inductance Coil. This special coil is designed to meet the exact sped-' fications of A. G. Cooley, whose "Rayfoto" receiver so many experimenters will build. For every inductance requirement AERO Coils are proved best — by experts and amateurs as well. Always specify AERO Coils if you want the finest in radio performance. AERO PRODUCTS, Inc. 1722 Wilson Avenue Chicago, 111. Cooley Ray-Foto Printer Unit The only available recorder for this assembly IJRESTO Machine Products, in close * association with Austin G. Cooley, inventor of the Cooley Ray-Foto Machine, is now manufacturing and accepting orders for the essential recording apparatus required for the complete assemble of this latest achievement in the science of radio. Write for details, prices, etc. Presto Machine Products Corp. 70 Washington Street Brooklyn New York ^3 for COOLEY "RAY-FOTO" We have a modulation transformer conforming to the specifications, for the COOLEY "RAY-FOTO" Apparatus. The Price is $050 Write us for details National Company, Inc. W. A. Ready, Pres. Maiden Massachusetts L I ON A Modulation Transformer