Radio Broadcast (Nov 1926-Apr 1927)

314 RADIO BROADCAST ADVERTISER The New Hammarlund-Roberts "Hi-Q" Receiver Embodies the Latest Hammarlund Developments The coils and variable condensers specified by the twelve nationally-known designer-engineers of the remarkable Hammarlund-Roberts "Hi-Q" Receiver are typical of Hammarlund advanced design and precision manufacturing methods. These instruments are of standard design and may be used with assurance of satisfaction in any other circuit of similar characteristics. The "MIDLINE' Conden'ser Gives better separation of wave lengths than previous types. Has a fullfloating rotor with removable shaft, adaptable to any scheme of single control, multiple condenser operation. "HAMMARLUND, JR." A high ratio, shielded midget condenser for use wherever small variable capacities and fine tuning are required. Base-board or one-hole panel mounting. Knob included. Some Other New Circuits in Which Hammarlund Products are Officially Specified COCKADAY "LC27" SARGENT "INTRADYNE'' LACAULT "LR4" HENRY-LYFORD ST. JAMES SUPER VICTOREEN SUPER MORRISON "VARION" NEW HARKNESS CARBORUNDUM PACENT "ULTIMAX" BROWNING-DRAKE POPULAR SCIENCE MONTHLY "POWERFUL' LOFTIN & WHITE The "AUTO-COUPLE " A scientifically correct tuned radio frequency assembly of Space-Wound Coil, "Midline" Condenser and Aluminum Shield, providing automatic graduated primary coupling at every condenser setting. We shall be glad to refer to the proper authorities any inquiries regarding the above receivers EQUALIZER A compact, efficient variable condenser of small capacity, for neutralizing or balancing radio frequency circuits against undesirable oscillations on the low wave-lengths. HAMMARLUND MANUFACTURING GO. 424-438 W. 33d Street, New York I lx 3<>^BiL£te/L Radio Ma m ma rlund P H C C tS /ON PRODUCTS Why not subscribe to Radio Broadcast? By the year only $4.00; or two years $2.40. Send direct to Doubleday, Page & Company, Garden City, New York. 5.00, saving F. D. PITTS COMPANY INCORPORATED 219-C Columbus Avenue, Boston, Mass., U.S.A. "Pioneers in the Distribution of Radio" DEALERS — Send for large and profusely illustrated catalog on the products of nationally advertised radio manufacturers. Wholesale Exclusively MERCHANDISING RADIO SINCE 1919 R343. Electron-Tube Receiving Sets. Receiver Radio Broadcast. Nov., 1926. Pp. 35-42. R. B. Lab. "Constructing the R. B. 'Lab.' Receiver," J. B. Brennan. A four-tube receiver, employing the Rice method of neutralization, is described. The volume is said to be sufficient to operate a loud speaker. The entire panel layout, and the method of assembly, are so planned as to give the shortest possible ieads. The latest parts are incorporated throughout. R210. Frequency; Wavelength. Frequency, Popular Radio. Oct., 1926. Pp. 534-fF. Wavelength. "Wavelengths to Frequencies," J. O. Perrine. The writer discusses at some length the advisability of using the term frequency instead of wavelength when speaking of the ether vibrations and the oscillations in radio circuits. It is brought out that, in using frequency, an equal division is always obtainable, which is not the case when speaking of wavelength. Charts for converting from frequency to wavelength, or vice versa, are given. 11800(347.7). Patent Practice. Patents, Radio Broadcast. Nov., 1926. Pp. 19-22. Radio. "The Radio Patent Structure and What It Means," F. Strother. It is stated that the radio industry at present is tied up with over 2400 patents, interlocking and meshing in a way which only extended patent litigation can untangle. Materials, ideas, methods, combinations of ideas and methods, are all subjects of patents. Of all of these probably the vacuum tube is in the greatest difficulty. Also the neutralization patents are a bone of contention at present. The belief is prevalent that, with the rapid advance of the art, the control of a basic idea does not rest in the basic patent, but rests in the patent upon some more recent refinement of the basic patent, or upon some new method of manufacturing the device. R090. History. History, Radiobroadcast. Nov., 1926. Pp. 28-31. Radio, "Looking Back Over Thirty Years of Radio," G. Marconi. Senatore Marconi gives a resume of the history of wireless Irom the time of his early pioneering and experimenting in the commercial wireless field, to the present dav when shortwave low-power beam transmitters are replacing those of longer waves and higher power. His discoveries in 1895 led to the erection of larger and larger stations which finally transmitted with enough power to consistently reach across the Atlantic Ocean. The importance of the discoveries of Fleming, DeForest, Langmuir, Armstrong, and others, have brought radio to its present high standing. R351. Simple Oscillator Transmitters. Transmitters, Radio Broadcast. B Battery. Nov., 1926. Pp. 32-34. "High Efficiency B-Battery Transmitters," l\. Henney. This article supplements the one appearing in the April issue of Radio Broadcast for 1926 (pp. 678 ff.) arid shows some of the transmitters which have been built by readers of Radio Broadcast. Each set is described, with comments on construction and operation. In tuning the set, a variety of curves are presented which aid greatly in determining what to look for when desiring maximum results. R343.5. Heterodyne Receivers. Super-Heterodyne, Radio Broadcast. Nov., 1926. Pp. 54-56. Shori"A short-Wave Super-Heterodvne Receiver," Wave G. J. Eltz, Jr. A short-wave receiver is described, which does not use the common regenerative method of reception, but the super-heterodyne principle. Since c.w. is supposed to be received with this set, the problem of distortion is not considered of paramount importance. An intermediate frequency of 22 kilocycles is used. The action of the receiver, which is a five-tube set, is summarized as follows: [. Approximate tuning to the incoming frequency by the first detector tube (which is also an oscillator) and the creation of a 22-kilocycle note. 2. Amplification of the 22-kilocycle note. 3. Detection of the beat note with: (a) Straight detector for telephone: (b) Oscillating detector for c.w. 4. Amplification at audio frequency. 5. One-dial control for the entire action. A description of the entire set is given with comments on construction and operation. Broadcasting, Regulation of. R5;o. Broadcasting. Radio Broadcast. Nov., 1926. Pp. 57-59. "A New Plan to Regulate Radio Broadcasting," C. Dreher. A solution of the problem of broadcast-wave allotments is suggested. The opinion is expressed that competition for the much-desired licenses be the method used in rationing them out. The question of merit, when a license to broadcast is desired, shall be decided by a check-up on program, power, and quality of transmission. In summary, the points to be considered are as follows: 1. Establishment of a suitable commission with power to rate broadcasting stations as to public service value or capacity, and facilities for determining the same. 2. Allocation of wavelengths on a population basis and with due regard for technical limitations. 3. Evaluation of hours of each day as to relative importance lor broadcasting. 4. Distribution of available time and wavelengths to applying stations according to individual ratings and values assigned to hours, exchange of hours to be permitted, subject to ratification by the commission. 5. Modification as necessary to secure flexibility and aptimum service to listeners. 6. Provision for judicial review of major decisions. R343. Electron-Tube Receiving Sets. Receiver, QST. Oct., 1023. Pp. 0-15. All-Wave. "Covering All Wavelengths," John M. Clayton. In an attempt to do away with a multitude of receivers to cover all I he radio frequencies from the 1;= to the 20,000-kc. band. Mr. Clayton has designed a receiver using plug-in coils in the Weagant circuit, with two stages of audio amplification. In order to take care of the variable capacity at this wide range of frequencies, a double condenser is used. I he complete layout and data concerning the plug-in coils are given. tAc Examined and approved by Radio Broadcast -fa