Radio Broadcast (May 1927-Apr 1928)

244 RADIO BROADCAST ADVERTISER Ionized Heliuni *Jhe Secret of afh EFFSCI ENTT l BE. nnHOUSANDS of radio users X know the satisfactory service given by Raytheon Long Life Rectifying Tubes, but few know the reason. The filament in the ordinary tube deteriorates while it is emitting electrons. In Raytheon, ionized helium gas, eighty times more conductive than copper, is used in place of a filament. This ionized helium supplies, over and over again, millions of electrons per second, with no deterioration to the helium. Thus, in Raytheon, each helium ion veritably becomes an endless chain of power. As a result, a Raytheon tube has a far longer life and affords sustained voltage throughout. Raytheon Manufacturing Co. Cambridge, Mass. When purchasing a /$<0® F0R "S^W/^ batteryeliminator.look t&-r% t_ W for the green seal (-f KciytneOn =7 which marks it as being v^. t ' Raytheon equipped. ^SJJJi/fe na\n\*t^ ^ The Heavy Duty Rectifier for B power service. Maintains a constant flow of smooth, silent power, at full voltage through TYPE BH ?ut its life' TyPe BH is standard in those units designed to supply the type 171 Amplifying tube. Rating: 125 m. a. at 300 V. Price $4.50. The tube that has made practical the elimination of A, B rr,~r T1 . and C batteries.The Raytheon1 Y I t. J3 A. equipped eliminator provides a noiseless constant flow of power. 350 m. a., 250 volts, $7.50. ^Raytheon1! ^ 10NG LIFE RECTIFYING TUBE ^ Manufacturers* Booklets Subjects Obtainable Free With the Accompanying Coupon JDEADERS may obtain any of the booklets listed below by use* ing the coupon printed on page 254. Order by number only. 1. Filament Control — Problems of filament supply, voltage regulation, and effect on various circuits. Radiall Company. 2. Hard Rubber Panels — Characteristics and properties of hard rubber as used in radio, with suggestions on how to "work" it. B. F. Goodrich Rubber Company. 3. Transformers — A booklet giving data on input and output transformers. Pacent Electric Company. 4. Resistance-Coupled Amplifiers — A general discussion of resistance coupling with curves and circuit diagrams. Cole Radio Manufacturing Company. 5. Carborundum in Radio — A book giving pertinent data on the crystal as used for detection, with hook-ups, and a section giving information on the use of resistors. The Carborundum Company. 6. B-Eliminator Construction — Constructional data on how to build. American Electric Company. 7. Transformer and Choke-Coupled Amplification— Circuit diagrams and discussion. All-American Radio Corporation. 9. Volume Control — A leaflet showing circuits for distortionless control of volume. Central Radio Laboratories. 10. Variable Resistance — As used in various circuits. Central Radio Laboratories. 11. Resistance Coupling — Resistors and their application to audio amplification, with circuit diagrams. DeJur Products Company. 12. Distortion and What Causes It— Hook-ups of resistance-coupled amplifiers with standard circuits. AllenBradley Company. 15. B-Eliminator and Power Amplifier — Instructions for assembly and operation using Raytheon tube. General Radio Company. 15a. B-Eliminator and Power Amplifier — Instructions for assembly and operation using an R. C. A. rectifier. General Radio Company. 16. Variable Condensers — A description of the functions and characteristics of variable condensers with curves and specifications for their application to complete receivers. Allen D. Cardwell Manufacturing Company. 17. Bakelite — A description of various uses of bakelite in radio, its manufacture, and its properties. Bakelite Corporation. 19. Power Supply — A discussion on power supply with particular reference to lamp-socket operation. Theory and constructional data for building power supply devices. Acme Apparatus Company. 20. Audio Amplification — A booklet containing data on audio amplification together with hints for the constructor. All American Radio Corporation. 21. High-Frequency Driver and Short-Wave Wavemeter — Constructional data and application. Burgess Battery Company. 46. Audio-Frequency Chokes — A pamphlet 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. 49. Bypass Condensers — A description of the manufacture of bypass and filter condensers. Leslie F. Muter Company. 50. Audio Manual — Fifty questions which are often asked regarding audio amplification, and their answers. Amertran Sales Company, Incorporated. 51. Short-Wave Receiver — Constructional data on a receiver which, by the substitution of various coils, may be made to tune from a frequency of 16,660 kc. (18 meters) to 1999 kc. (150 meters). Silver-Marshall, Incorporated. 52. Audio Quality — A booklet dealing with audio-frequency amplification of various kinds and the application to well-known circuits. Silver-Marshall. Incorporated. 56. Variable Condensers — A bulletin giving an analysis of various condensers together with their characteristics. General Radio Company. 57. Filter Data — Facts about the filtering of direct current supplied by means of motor-generator outfits used with transmitters. Electric Specialty Company. 59. Resistance Coupling — A booklet giving some general information on the subject of radio and the application of resistors to a circuit. Daven Radio Corporation. 60. Resistors — A pamphlet giving some technical data on resistors which are capable of dissipating considerable energy; also data on the ordinary resistors used in resistancecoupled amplification. The Crescent Radio Supply Company. 62. Radio-Frequency Amplification — Constructional details of a five-tube receiver using a special design of radiofrequency transformer. Camfield Radio Mfg. Company. 63. Five-Tube Receiver — Constructional data on building a receiver. Aero Products, Incorporated. 64. Amplification Without Distortion — Data and curves illustrating the use of various methods of amplification. Acme Apparatus Company. 66. Super-Heterodyne — Constructional details of a seven-tube set. G. C. Evans Company. 70. Improving the Audio Amplifier — Data on the characteristics of audio transformers, with a circuit diagram showing where chokes, resistors, and condensers can be used. American Transformer Company. 72. Plate Supply System — A wiring diagrani and layout plan for a plate supply system to be used with a power amplifier. Complete directions for wiring are given. Amertran Sales Company. 80. Five-Tube Receiver — Data are given for the construction of a five-tube tuned radio-frequency receiver. Complete instructions, list of parts, circuit diagram, and template are given. All-American Radio Corporation. 81. Better Tuning — A booklet giving much general information on the subject of radio reception with specific illustrations. Primarily for the non-technical home constructor. Bremer-Tully Manufacturing Company. 82. Six-Tube Receiver — A booklet containing photographs, instructions, and diagrams for building a six-tube shielded receiver. Silver-Marshall. Incorporated. 83. Socket Power Device — A list of parts, diagrams, and templates for the construction and assembly of socket power devices. Jefferson Electric Manufacturing Company. 84. Five-Tube Equamatic — Panel layout, circuit diagrams, and instructions for building a five-tube receiver, together with data on the operation of tuned radio-frequency transformers of special design. Karas Electric Company. 85. Filter — Data on a high-capacity electrolytic condenser used in filter circuits in connection with A socket power supply units, are given in a pamphlet. The Abox Company. 86. Short-Wave Receiver — A booklet containing data on a short-wave receiver as constructed for experimental purposes. The Allen D. Cardwell Manufacturing Corporation. 88. Super-Heterodyne Construction — A booklet giving full instructions, together with a blue print and necessary data, for building an eight-tube receiver. The George W. Walker Company. 89. Short-Wave Transmitter — Data and blue prints are given on the construction of a short-wave transmitter, together with operating instructions, methods of keying, and other pertinent data. Radio Engineering Laboratories. 90. Impedance Amplification — The theory and practice of a special type of dual-impedance audio amplification are given. Alden Manufacturing Company. 93. B-Socket Power — A booklet giving constructional details of a socket-power device using either the BH or 313 type rectifier. National Company, Incorporated. 94. Power Amplifier — Constructional data and wiring diagrams of a power amplifier combined with a B-supply unit are given. National Company, Incorporated. 100. A, B, and C Socket-Power Supply — A booklet giving data on the construction and operation of a socketpower supply using the new high-current rectifier tube. The Q. R. S. Music Company. 101. Using Chokes— A folder with circuit diagrams of the more popular circuits showing where choke coils may be placed to produce better results. Samson Electric Company. 22. A Primer of Electricity — Fundamentals of electricity with special reference to the application of dry cells to radio and other uses. Constructional data on buzzers, automatic switches, alarms, etc. National Carbon Company. 23. Automatic Relay Connections — A data sheet showing how a relay may be used to control A and B circuits. Yaxley Manufacturing Company. 25. Electrolytic Rectifier — Technical data on a new type of rectifier with operating curves. Kodel Radio Corporation. 26. Dry Cells for Transmitters — Actual tests given, well illustrated with curves showing exactly what may be expected of this type of B power. Burgess Battery Company. 27. Dry-Cell Battery Capacities for Radio Transmitters— Characteristic curves and data on discharge tests. Burgess Battery Company. 28. B Battery Life — Battery life curves with general curves on tube characteristics. Burgess Battery Company. 29. How to Make Your Set Work Better — A nontechnical discussion of general radio subjects with hints on how reception may be bettered by using the right tubes. United Radio and Electric Corporation. 30. Tube Characteristics — A data sheet giving constants of tubes. C. E. Manufacturing Company. 31. Functions of the Loud Speaker — A short, nontechnical general article on loud speakers. Amplion Corporation of America. 32. Meters for Radio — A catalogue of meters used in radio, with connecting diagrams. Burton-Rogers Company. 33. Switchboard and Portable Meters — A booklet giving dimensions, specifications, and shunts used with various meters. Burton-Rogers Company. 34. Cost of B Batteries — An interesting discussion of the relative merits of various sources of B supply, Hartford Battery Manufacturing Company. 35. Storage Battery Operation — An illustrated booklet on the care and operation of 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. Why Radio Is Better with Battery Power — Advice on what dry cell battery to use; their application to radio, with wiring diagrams. National Carbon Company. 53. Tube Reactivator — Information on the care of vacuum tubes, with notes on how and when they should be reactivated. The Sterling Manufacturing Company. 54. Arresters — Mechanical details and principles of the vacuum type of arrester. National Electric Specialty Company. 55. Capacity Connector — Description of a new device for connecting up the various parts of a receiving set, and at the same time providing bypass condensers between the leads. Kur7-Kasch Company. 69. Vacuum Tubes — A booklet giving the characteris ' tics of the various tube types with a short description of where they may be used in the circuit. Radio Corporation of America. (Continued on page 254)