Radio Broadcast (May 1928-Apr 1929)

300 RADIO BROADCAST ADVERTISER For Better, Clearer Radio tiion AGAIN CeCo blazes the /\ trail in radio engineering achievement by introducing the popular Screen Grid Tube in an A. C. type: — the AC22. The CeCo line of A. C. tubes is most complete, embracing practically every existing type. CeCo Tubes are carried in stock by dealers everywhere. Write us for unusual and interesting booklet entitled "Getting the most out of your Radio" CeCo MANUFACTURING Co., Inc. PROVIDENCE, R. I. (Continued from page 304) The Elements of Radio-Communication. By O. F. Brown, with a Foreword by Admiral of the Fleet Sir Henry B. Jackson. Oxford University Press. New York, 1927. 216 pages. S3. 50 TN HIS foreword Admiral Jackson recommends this text on radio communication to -I those who, like himself, have no mathematical abilities. It is not intended for radio specialists as much as for those outside the profession who wish to gain some knowledge of radio operations through the study of a moderately technical work. The danger in all such efforts is that the results will seem slight to the serious radio engineer, even when the text used may present grave difficulties to many of its students. Sir Henry thinks that Mr. Brown's book should appeal "to the public generally who wish to know how broadcasting works without having to study mathematical formulae." It seems 'to the reviewer that the book is too technical for this audience. Sir Henry's thirty-odd years in radio work lead him to minimize many difficulties which exist for people without his background. Chapter 1 contains some historical treatment of the subject which, to critical American readers, will appear somewhat over-simplified, insular, and not inclined to give full credit to the work of German and American pioneers. The following chapters discuss such subjects as high-frequency alternating currents, transmission of damped and continuous waves, thermionic valves, radio telephony, and directional reception, with considerable clarity and about the same degree of detail with which a college text on physics tackles the problems of mechanics and optics. This entails some faults of omission, as in Chapter 8, where the author, after itemizing the defects of commercial carbon microphones, turns abruptly to condenser transmitters, apparently ignoring the existence of high quality carbon microphones. In his chapter on "Short-Wave Transmission and Reception" Mr. Brown includes a graceful compliment to the amateurs, whose work he calls "extremely brilliant," and he goes on to say: "There is little doubt that the remarkable results of these men had in no small measure the effect of causing other experts to investigate and consider seriously the possibilities of short waves." The last chapter, on the " Nature and Origin of Atmospherics," contains an interesting account of the research work of Watson Watt and E. V. Appleton and should be read by engineers interested in this special branch. — Carl Dreher. Something to Omit IF I were a Radio Commissioner, which God forbid, the first stations which I should banish from theair arethosewhich announce grandly at the beginning and end of each transmission period that they maintain their assigned frequency with a quartz crystal standard. That is as if you went to some Vice President and asked him to give you a job because you clean your teeth every morning with dental floss and come to the office without poisoning policemen's horses or assaulting shop girls. A radio station is bound by law to stay on its assigned frequency. How it does it is surely none of the public's concern. It can do it, for all the listeners care, by hanging a piano on the aerial or uttering prayers. The act requires no more mention than any other act of public decency. The listeners want entertainment; the correct functioning of the transmitter may be taken for granted. To argue otherwise indicates a strange misunderstanding of the normal proprieties. — Carl Dreher. Eicitisivety [rrenjed by Tecn8it*yne Car oora'.ion under U. S Patents Nos. 1553558 1034 103, 1034 104 Control Your Volume! T0NATR0L Complete line of Volume Controls OBSERVE this caution in building your receiver. Make sure you can control the volume smoothly and easily by incorporating Tonatrol in the circuit. Tonatrols are the highest development in volume controls and are designed in types to meet the special requirements of all A.C. or conventional battery circuits. Also furnished with filament or power switch) attached. Electrad specialises in a full li?ie of controls for all radio purposes. Write for FREE descriptive circulars. Dept. M-9, 175 Varick Street New Tork ELECTRAD Do You Use AC Tubes? Then you should read John F. Rider's new book "AC Tubes . . . . How to Use Them" The first book devoted to AC tube problems encountered by the AC tube user . . . Are you having trouble with your AC receiver . . . with your AC power amplifier. No matter what your AC tube problem, you'll find the solution in this book . . . It will protect your AC tube investment . . . Learn how to use AC tubes .... They are as good as their DC brothers, if correctly used. Read this book and save money. Price $1.00. Write for list of other books RADIO TREATISE CO. 270 Madison Ave. New York City MAIL THIS COUPON Here is my $1.00 for the "AC tube . . . How to Use Them" book by John F. Rider, to be mailed postpaid in U. S. and Canada to Name Address City . State.