Radio Broadcast (Nov 1926-Apr 1927)

434 RADIO BROADCAST ADVERTISER USE THESE COILS AND IMPROVE ANY RADIO RECEIVER INDUCTANCE UNITS Tuned Radio Frequency Kit $12.00 Replace your present inductances with this Aero Coil Tuned Radio Frequency Kit. It will positively improve the performance of your receiver. Special patented Aero Coil construction eliminates radio frequency losses. You will notice instantly, a tremendous improvement in volume, tone, and selectivity. This kit consists of three matched units. The antenna coupler has a variable primary. Uses .00035 condenser. Coils are uniformly air spaced. No dope is used. Consequently they tune into resonance on a "knife's edge." FREE with Each Kit Eight-page color circuit, layout and instruction sheet for building the super-sensitive 5-tube Aerodyne Receiver, packed with each kit. Extra copies — 75c each. Instructions include insert showing how to wire up for a power tube if desired. Get these coils from your nearest dealer. If he can't supply you, order direct from the factory AERO PRODUCTS, Inc. Dept. 109 1772 Wilson Ave. Chicago, 111. j; Bradjgyometer \ ^ THE PERFECT POTENTIOMETER J| jjj Uses graphite disc resistors which are ■C noiseless and not J« affected by atmos■" pheric conditions. ■B Metal parts are nickel '■plated. One hole mounting. Finish ".and knob match Ji Bradleystat. Made in + 200 and 400 ohm •fi ratings. > ^gn-Biai^ Ca < mm Electric Controlling Apparatus J" 2 78 Greenfield Avenue Milwaukee, Wig. J* THE "RADIO BROADCAST" INFORMATION SERVICE to Write jor I echnicat Lnfot' mation — The Scope of This Service AS WAS announced in the June Radio /-\ Broadcast, all questions which were formerly sent to "The Grid" will now be handled by the Technical Information Service, Radio Broadcast Laboratory. That service is maintained under the following rules: 1. All questions from subscribers to Radio Broadcast will be answered free of charge. 2. Non-subscribers to Radio Broadcast will be charged a fee of One Dollar for the Laboratory Technical Service. 3. All questions will be answered by mail and none will be published in Radio Broadcast. The Technical Information Service of the Laboratory feels that it is important to define the scope of its service to readers. Although the Service is of very general help to our readers, there are certain demands which can not be met. The Technical Information Service: 1. Cannot make comparisons between various kinds of receivers or manufactured apparatus. 2. Wiring diagrams of manufactured receivers cannot be supplied. This information can be secured from the various manufacturers. 3. Complete information cannot be given about sets described in other publications, but in all cases (wherever possible), inquirers will be referred to a source of information where the data can be obtained. In this connection, the monthly department in Radio Broadcast "The Best in Current Radio Publications" should be of great help, and should be consulted. That department records the most important constructional, technical, and general radio articles which appear. 4. Special receivers or circuits cannot be designed by the Technical Service. 5. Those who ask questions which cannot be answered in the scope of a letter will be referred, if possible, to sources where the information can be obtained. TECHNICAL INFORMATION INQUIRY BLANK Technical Service, Radio Broadcast Laboratory, Garden City, New York Gentlemen: Please give me fullest information on the attached questions. I enclose a stamped addressed envelope. □ I am a subscriber to Radio Broadcast, and therefore will receive this information free of charge. □ I am not a subscriber and enclose $1 to cover cost of the answer. j^ame Address R. B. F. "Radio Broadcast" Booklets HOME constructors who wish to obtain complete blueprints and constructional information on the R. B. Impedance-Coupled Browning-Drake receiver as described in this magazine for September, 1926 can secure a set by fowarding their order, together with remittance for $1 to Radio Broadcast, Booklet department, Garden City, New York. Other blueprint sets which are sold at the same price are those on the four-tube Roberts receiver, and the "Aristocrat" receiver. MODEL 100 TUBE TESTER Tester is still as popular as ever and in use by many thousands of Radio dealers and jobbers. It will give all the usual tests in determining whether tubes are good or not, and with a minimum of time. List price, with full instructions, #35 Send for booklet, "Hoyt Meters for Radio" B-2 Burton-Rogers Company Sales Dept. for Hoyt Electrical Instrument Co. Boston Mass. Save Wto50% FREE RADIO CATALOG Get the lowest rock-bottom prices on radio parts, sets, kits. New free Radio Catalog and Guide brimful of standard, reliable, guaranteed goods. 164 pages of latest hook-ups and illustrations. Be sure to get this thrifty book before you buy. It puts money in your pocket. Saves you as much as half on a set. Also please include name of radio fan. Send letter or postal NOW for newest 192 7 edition. THE BAR AWI K COMPANY 540-549 Monroe St., Chicago, TJ. S. A. Why not subscribe to Radio Broadcast? By the year only $4.00; or two years 56. 00, saving $2.40. Send direct to Doubleday, Page €s? Company, Garden City, New York. WORLD S FINEST LOUD SPEAKER, — GENUINE — "ENSC0"3^C0NE KIT ONLY v& ONLY $10 NO THE SOLUTION OF THE PERFECT DISTORTION LOUD -SPEAKER PROBLEM FIDELITY Choice of {kodingTngmeers Make Your Own Three Foot Cone Speaker In Less Than An Hour Complete parts furnished in kit form. We guarantee this speaker the equal of any manufactured cone speaker at any price. With this THREE FOOT CONE SPEAKER you hear all the tones. It brings out the true depth and beauty of orchestral and instrumental music. Can be operated softly for living room music or full volume for dancing, and without trace of distortion. Kit includes famous "ENSCO" cone unit, the only direct-drive, distortionless unit for large cones; Alhambra Fonotex for big cone, with brass apex, two Sepia Prints showing cabinet or stand, wall, or roll type construction for cone speaker. All necessary instructions. Buy this wonderful speaker under our absolute guarantee. 1'oiir money back if you are not convinced that it is the finest reproducing medium obtainable at any price. II works on any set, with ordinary Tubes or with Power Output.* SEND NO MONEY! Write your name plainly as indicated Del mail and complct then will be forwarded to you. Just pay postman $10.00 upon delivery. Name Address ENGINEERS' SERVICE CO. 85 Church St. Desk X New York City