Radio Broadcast (May 1929-Apr 1930)

RADIO BROADCAST ADVERTISER. KEEP PACE WITH THE NEWEST! EVE READY RAYTHEON TUBES FOR TELEVISION AND TALKING PICTURES Eveready Raytheon Eveready Raytheon FotP'CeU ARE OF PROVED DEPENDABILITY AND PERFORMANCE The Eveready Raytheon Kino-Lamp for television reception is the first tube developed commercially which will work with all systems. With its uniform glow over the entire plate . . . tested performance . . . long life . . . perfect reproductive qualities . . . the Eveready Raytheon Kino-Lamp is a great step forward in television. The Eveready Raytheon Foto-Cell is a long-life transmitting tube for television. Used also for talking pictures. Made in two sizes, either hard vacuum or extra-sensitive gasfilled. Correspondence is invited from everyone interested in television. Foto-Cells to special specifications will be made at reasonable prices. NATIONAL CARBON CO., INC. General Offices: New York, N. Y. Unit oi Union Carbide and Carbon Corporation ^The Spirit of Accuracy SETTING standards is half the work of science. The standard of length — a platinum-iridium bar; the standard of time — stars passing the hair line on a lens. And in radio — the standard of reception. This is the ultimate goal of the radio engineer. Progress toward that standard depends upon the uniform excellence of the tubes used for tests. The Spirit of Accuracy enters into every Arcturus Tube and is manifest in each test, check and process of manufacture. Oxides filtered through sieves that hold water... gauges that detect the fraction of a hair's breadth... a vacuum that approaches nothingness— all contribute to the standard the engineer demands. Radio engineers use Arcturus A-C Tubes with the sincere assurance that these tubes are as fine and uniform as it is humanly possible to build them — a new standard in radio tubes. BLUE Ioi&Sji* TUBES ARCTURUS RADIO TUBE COMPANY, Newark, N. J. COPERNICUS From the Tainting by Otto Brausewetter A Complete Line of Quality Volume Controls ■ Superior workmanship, smooth operation and long life characterize the ELECTRAD TONATROL Made in a var^^T^I^I^^^^ iety of values suitable for most circuits. One of the most popular of the many Electrad Voltage Control devices TONATROL IH with manufactur '' ers, cus tom-set builders and experimenters. Supplied U. S. Pats. M ■ , with or without fila 1593658 I ment switch. List, 1034103' X| | $1.50 to $3.00. HU HH The Super TONATROL— the remarkable new Electrad Volume Control for use in high-voltage receivers. Entirely different in construction and design. Easily dissipates 5-watts. Resistance element fused to an enameled metal base. Pure silver floating contact gives amazing smoothness. Seven typeswith uniform ortapered curve. List, $2.40 to $3.50 .COUPON1-___ ELECTRAD, Inc., Dept. RB8> 175 Varick St., New York Please Ncml TONATKOL ami SuperTONATROIi Literature. Name Address ELECTRAD • AUGUST 1 9 29 • Jenkins & Adair Level Indicator Panel Type B (Calibrated) For Broadcasting, Electrical Recording, and Power Speaker Systems The Type B Level Indicator Panel is designed for direct reading of the voice level on any 500-ohm telephone circuit, the range being from minus 10 TU to plus 2 0 TU, in steps of 2 TU each. The parts consist of an accurately built input transformer, a specially designed potentiometer, a filter retard and condenser, and direct current galvanometer calibrated for this work. The use of this panel is essential wherever a specific level must be maintained. The calibration is highly accurate, and cannot alter while the tube constants remain normal. The potentiometer is built up of nichrome wire units, held to an accuracy of 1 /10 of 1%. The panel is extremely simple in operation, is direct reading in TU's, and minimizes the change of load on the measured circuit when the level settings are changed. This last feature is a great improvement over present types. The dimensions of this panel are 19 x IVz in. It is of 5/16 in. black sanded bakelite and weighs, complete, IS lbs. It operates on 12 volt A battery and 135 volts B battery, and requires a 102E tube (not furnished by us). The parts of this panel are NOT sold separately. Bulletin 8 gives a more complete description and will be mailed on request. The net price in the United States and Canada is §250.00 t o. b. Chicago. J. E. JENKINS & S. E. ADAIR Engineers 1500 N. Dearborn Parkway Chicago U. S. A. Manufacturers of Recording Amplifiers EVEREADY RAYTHEON