Radio age (Jan 1927-Jan 1928)

kajjiu ALrH for April, iyz/ These Coils Improve Any Radio Receiver ! T. R. F. KIT— List $12.00 THIS set of supersensitive Aero Tuned Radio Frequency Coils has never failed to improve the performance of any radio receiver. Tremendously increased power, extreme selectivity, and improved tone quality are sure to result from their use. This kit of Aero Coils has a much lower high frequency resistance than other types of inductances. You should use them in any circuit, if you want the best possible results. TRIPir Big 8-page 4-colored layout system ■* *VL.J-» (actual size blue prints) and complete instructions for building the 5-tube AeroDyne Receiver free with eaoh kit. Also insert showing how to wire for a power tube if desired. Extra copies, 75o each. Get these Aero Coils from your dealer. If he is out of stock, order direct from the factory. AERO PRODUCTS, Inc. Dept. 106 1772 Wilson Ave. CHICAGO, ILL. IpPsiSS! BIG NEW 1927 CATALOG-FREE Dealers, Agents, Set Builders -get ear big 1927 Catalog — 225 nationally advertised lines. Lowest pricea in America! Largest, most complete stock. Radio's latest developments. It's FREE— send for your copy now. AMERICAN AUTO & RADIO MFG. ~~ 1S7S AMAZING INVENTION FOR ANY RADIO Why confine your radio programs to a few local station! when the expensive concerts, dance music and leetures ef hundreds of big cities aro ready you? Connect this DM— B GETTER to yew tune according to lastructlons and presto — not* the distant programs roll Inl Satisfaction Guaranteed Yiur money instantly refunded If you are not satisfied. The article on proper tuning, furnished FREE with each Distance Getter, alone is worth the price. Galloway of I writes: "Results beyond all expeei thru locals like a knife." Heme* ef , i, HI., says: "Send three more for mj taW Is. I get Denver and California easily." ^eV MAIL COUPON TODAY1 HAZLETON LABORATORIES 4SM Maiden St.. Dept. RA, Chleai*. III. Send me Distance Getter, postpaid. Xhelosed find $1.00 (M. O., stamps or check). Send C. O. D. plus small postage added. Address An Improved Refuse Burner The burner shown in the accompanying picture has two or three advantages which anyone with a garden will appreciate. It consists of a twenty inch length of a hot water boiler sawed off and attached to a three inch pipe which is set vertically in the ground. The pipe was attached to the box by cutting a hole through the box of the right size, inserting the upper end of the pipe through and then spreading the pipe to hold it solid. There are several holes through the side of this box to promote combustion. Refuse which is raked up at intervals about the place is placed in here and set afire. If the day is windy a sheet of screen is laid over the top to prevent flying sparks. Thus the fire burns out with no harm whatever and the ashes can be removed once or twice a season Higher Tones Easier For Ear to Detect THE reason why the notes of a cornet can be heard farther away than can the notes of the bass horn has just been elucidated by B. A. Kingsbury, an experimenter of the Bell Telephone Laboratories. The shrill notes of the higher-pitched instruments "carry" better, musicians say, than do tones lower in pitch. The secret does not lie, however, in any difference in the carrying power of the tones through the air. It is a matter, Mr. Kingsbury finds, of the human ear; not of the tones or of the air that carries them. Comparative studies of the loudness of different tones, as judged by a number of persons with normal ears, show that high-pitched tones are heard more easily than lower ones. When the same amount of physical energy is present in two tones, one low and the other high, the higher tone will sound much louder to the average ear than does the lower one. RADIO'S LEADING PUBLICATIONS The CITIZEN'S RADIO CALL BOOK is Radio's Greatest Publication. Contains all the latest information of construction so simply told anyone can build superheterodynes as easily as laboratory men. Large Picture section contains beautiful photos of leading station announcers and entertainers. Also contains the most complete list of the World's broadcasting stations — every one — their transmitting schedules, wave lengths, slogan and plenty of space under each to log that station for future reference. Really Radio's Greatest Publication. You'll be delightet. Price only 50 cents postpaid. The CITIZEN'S RADIO AMATBUK CALL BOOK is an international Hit of call letters, names and addresses of the World's amateur transmitters. Compiled from official sources and the moat authentic list obtainable anywhere. Remember, the whole World — U. S., Canada, England, Australia, France, Oarmany, etc. The whole international lift. Also commercial ship and land station*. Price only 75 cent* postpaid. If you are unable to obtain either of the above mentioned publications from your news dealer or radio store, they will be sent postpaid upon receipt ef the amount in U. S. stamps, coin, check or P. O. money order. Citizens Radio Call Book 508 S. Dearborn St. Chicago Illinois Please Mention Radio Age When Writing to Advertisers.