Radio Broadcast (May 1928-Apr 1929)

388 RADIO BROADCAST ADVERTISER AmerJkan r Push-Pull Power Stage for Dynamic Speakers For best results, every dynamic type speaker should be preceded by a pushpull amplifier. This is particularly true because they reproduce frequencies as low as 30 cycles and the attendant hum from raw AC on the filaments of power tubes is greatly pronounced unless filtered out by a push-pull amplifier. The AmerTran completely wired push-pull power stage has been specially designed for dynamic speakers. Consists of type 151 input and output transformers (zoo for working out of 2.10 type tubes or type 362. for 171 type tubes). Both the zoo and the 361 have the secondary designed for connecting directly to the moving coil of the speakers. Completely wired with sockets and resistances. Also available for cone type speakers and for both 2.10 and 171 tubes. Licensed under patents owned or controlled by RCA and may be bought with tubes. Price complete (without tubes) $36.00 (slightly higher west of Rocky Mountains) "Write us for hook-up of this remarkable instrument. AMERICAN TRANSFORMER COMPANY Transformer Builders for more than 28 years 283 Emmet Street, Newark, N. J. -against 30 seconds to a minute for other tubes... Arcturus 127 A-C Detector Tube — quickest acting, longestlasting... Proved by test to have useful life far in excess of 1,000 hours... For quicker action, better tone, longer tube life — put an Arcturus A-C Long Life Tube in every socket. ./'Get Action with Arcturus Tubes — quicker, better." Arcturus radio company 255 Sherman Avenue Newark, New Jersey TURU Letters from Readers (Continued from page 386) To the Editor: In a spirit more of sorrow than of censure, I am writing to call your attention to what appears to be a grave discrepancy in a certain paragraph notice contained in the copy headed "Here and There" on page 255 of your September issue. And to think that said discrepancy should occur in the same issue in which the little article "Our Mistake" unfolds its shameful tale, is enough to make any lover of Radio Broadcast break down and weep. However, you evidently said your "prayer to the radio gods" with little or no faith, for, lo, the "letters are already commencing to come in". Which "ain't no way to pray"! Now don't think for one moment that / discovered above mentioned error — for I didn't; I am chronically near-sighted and sadly afflicted with "neglectitis" when it comes to details — how I loathe the word! But one of our Arguseyed announcers (he's lots of other things around here, too) sorrowfully pointed it out to me — "and to think it's in our dear ole Radio Broadcast too," he sobbed. And so, I hurried straightway to my typewriter and decided to call your attention to it immediately, thinking maybe you might wire that Mencken man that you'd found his "million-dollar-a-year proof reader", as that salary would come in right handy. On Page 255 in September issue, you will note, in black and white, that the "cost of broadcasting the Republican National Convention through 42 stations amounted to $77,000, or a little over a dollar a minute." And right there we've got you! You mean seconds, of course. For had the Grand Old Party been on the air 72,000 minutes as you say, it would have sure been some convention, as it would have broadcast 1200 hours or 50 days. Beats the Democratic 1924 record by about 4 weeks solid. Gene Brown, (Station wbal) Baltimore, Md. Furthermore, we ourselves have also discovered a few typographical pecadilloes, which we are not going to mention for the reason that we want to keep our job. Java on the Air CROM George E. Morcroft, Pittsburg, Pa., * comes this interesting news of the new radiotelephone service between Holland and Java: To the Editor: In your September issue (page 256) I noted a little news excerpt in which you told of the opening of a high-frequency radiotelephone system between Holland and Java, but you were unable to give details "as the dispatch from abroad was garbled." If you are interested in further information as to these stations I would like to say that the Dutch station involved is pcll at Kootwijk, Holland, on a frequency of 16,300 kc. with a power input of 32 kilowatts. I have often received this station and have had reception confirmed. The Java end is taken care of by two transmitters which are modulated at the same time, according to a letter I have just received from the Chief of the Radio Laboratory at Bandoeng, Java, confirming my reception of one of these stations, anh. The two transmitters are anh, at Malabar, Java, on a wavelength of 17.0 meters, and ane at Bandoeng, Java, on 15.93 meters. The letter from Java also contains the information that music is broadcast several days a week from ane on a wavelength of 15.93 meters from 1300 G. C. T. to 1750 G. C. T. (8 a. m. — 12:50 p. m. — Eastern Standard Time). The telephone communications are carried on on Tuesdays and Thursdays from 1500 G. C. T— 1700 G. C. T. (10 a. m— 12 noon E. S. T.). pcll at Kootwijk, Holland, also {Continued on page 390)