Radio broadcast .. (1922-30)

RADIO BROADCAST ADVERTISER IN A HUDDLE? Yes!— But it's not a Football Signal They're looking at the NEW WESTON TRIPLE-RANGE A. C. VOLTMETER for measuring theA.C. supply and tube voltages in connection with A. C. RECEIVERS Model 150/8/4 volts THIS new A. C. portable voltmeter— the latest addition to the famous Weston line of Radio Instruments—has been eagerly awaited by the entire fra- ternity of radio interests, experimenter and set owner alike. With the advent of the new A. C. receivers, everywhere one heard the question—"What kind of an instrument do we need now?" And here it is, an exquisite design, typically Weston in construction and performance. The highest quality, yet moderately priced. See your dealer and place your order now. Get in ahead of that inevitable rush when Weston an- nounces a new development. WESTON ELECTRICAL INSTRUMENT CORPORATION 179 Frelinghuysen Ave. Newark, N. J. WESTON RADIO INSTRUMENTS PRINCIPLES OF RADIO COMMUNICATION. By J. H. Morecroft. Second Edition. Published by John Wiley & Sons, Incorporated, New York. Pages, looi. Illustrations, 831. Price, $7.50. M 'ORrXROF T has gone into a second edi- tion. The revised volume calls for a sup- plementary review, for after the lapse of six years (the first edition was issued in 1921) much that was important is slipping into desue- tude, and technological fancies have become engineering realities. The ordinary engineer, called on to review Morecroft's monumental work, is placed somewhat in the position of a parish priest ordered to review the Bible. It is safe, however, to quote Professor Morecroft himself in his outline of the changes made in the new edition: The new material incorporated in this edition so increased the size that it was thought advisa- ble to delete much of the first edition. A consider- able part of the chapter on Spark Telegraphy has been taken out, therefore, and two chapters of the earlier edition have been deleted. The chapter on radio measurements, and that on experiments, have been omitted. Notable additions to the older edition occur in Chapters II, IV, VIII, and X. In Chapter II many new data on coils and condensers at radio frequencies are given. In Chapter IV, dealing with the general features of radio transmission, new material on field strength measurements, reflection and absorption, fading, short-wave propagation, etc., has been introduced. In Chap- ter VIII (radio telephony) a great deal of ma- terial on voice analysis has been added; the per- formance of loud-speaking telephones, frequency control by crystals, etc., has been discussed. In Chapter X, dealing with amplifiers, the question of distortionless amplification has been thor- oughly dealt with, some of the material being given for the first time. The questions of radio- frequency amplification, balanced circuits, push- pull arrangements, etc., have been explained. Principles of Radio Communication is a com- prehensive textbook of radio engineering. The author, a Professor of Electrical Engineering at Columbia University, and a Past President of the Institute of Radio Engineers, is one of the outstanding opponents of guesswork in radio technology. When the publishers in their circular describing the book refer to it as the "most complete, accurate, and authoritative book on radio available" they are simply telling the truth. But in justice to the author, who has put a considerable number of years into this job, it should be stated that when the publishers con- tinue: "—for Designers, Engineers, Service Men, Distributors, Dealers, Salesmen, Teachers, Students, Operators, Set Owners," they talk like hasheesh addicts. I hope that Wiley sells as many copies of Morecroft as the publisher of Durant's Story of Philosophy has managed to dispose of, to his own and his client's en- richment, but I feel bound to warn Distrib- utors, Dealers, Salesmen, and Set Owners that, with negligible exceptions in their ranks, the only portions of Principles of Radio Communica- tion which they can hope to understand are the articles and prepositions. Not that it is an excessively abstruse work; any student of mathematics through the calculus can follow the demonstrations, and any student of radio en- gineering can read the whole thousand pages with vast profit. But it is a work in radio en- gineering. Its precise virtue is that dealers, salesmen, and the generality of set owners will not understand it. How radio has grown! Here is a book of a thousand six-by-nine pages, and yet it is largely an outline of principles. If you consulted it for the actual design of a line equalizer or a lo-TU Free 1928 Radio Guide The big Barawlk Radio Guide book is used by hundreds of thousands of radio enthusiasts. It's the handiest and most reliable radio reference guide, and a big money-saver. Keep up to date by utilizing Barawik service. 4OOO Radio Bargains It shows pages replete with reliable informa- tion about the newest and most advanced ideas in A-C radio developments. It will keep you posted on what's up to date. Lowest Prices on Parts Standard Discounts to Dealers, Set Builders, Agents. It will pay you to get our prices for complete parts for the popular circuits featured in RADIO BROADCAST and other magazines. Whenever a new circuit appears for which you want complete parts, write or wire us and they'll be on their way to you quickly. We know what parts to send you. Simply give name of circuit and we'll take care of the rest. We guarantee you a big sav- ing on every order. Send for Free Copy Now! Get our new radio cata- og to-day before you spend another cent on radio Just mail the coupon and free copy will be sent you. Dept. 833 Chicago. U. 8. A. Mall Tills Coupon Now! For Free Copy Name Address TO 'RADIO DEALERS/ The R. B. Laboratory Informa- tion Sheets have been appear* ing in RADIO BROADCAST since June, 1926. They are a regular feature in each issue and they cover a wide range of infor- mation of value to the radio experimenter and set builder. We have just reprinted Lab. Sheets Nos. 1-88 from the June, 1926, to April, 1927, issues of RADIO BROADCAST. They are arranged in numerical order and are bound with a suitable cover. They sell at retail for one dollar a set. Write for dealers' prices. Address your letter to Circulation Dept., RADIO BROADCAST Garden City, N. Y.