Radio age (Jan 1927-Jan 1928)

RADIO AGE for April, 1927 41 LECTOl CE NC ■^ TRANSFORMERS " TESTED MATCHED GUARANTEED Designed by E. H. Scott, whose famous receiver, the WORLD'S RECORD SUPER, established FOUR world records for long distance reception. HIGHEST AMPLIFICATION FINEST TONE QUALITY SELECTONE Untuned Transformer — B400 — haB specially designed closed Iron core, which limits interstage coupling and is impregnated in a vacuum so that all characteristics of coil remain constant. The coll design gives an extremely high amplification. Caa be used in any circuit requiring a long wave transformer. PRICE $6.00 PERFECTLY MATCHED GREATEST SELECTIVITY SELECTONE Tuned Stage Transformer — K410 — is air core. The matching of these filters is so perfect that where extreme selectivity is desired, two can be used and are guaranteed to match perfectly. PRICE $6.00 Either 199 or 201A Tutes Can Be Used I"? D 17 17 Send for illustrated literature w* t\r,r, describing Selectone Trans ******* formers and tests they undergo. If your dealer cannot supply you, order direct SCOTTi TRANSFORMER CO. 7620 Eastlake Terrace, Chicago, 111. MFD. Modelg-5 . ie, Roberts i mi! ,-.. r',, ,■:,..):-■. Price Sl.OC A Blight turn obtains c frequency circuitB. N Drake. McMurdo Silver'* capacity range 1.8 to 20 r ' Model * With grid clips obtains the proper grid capacity on Cockaday circuits, nlterfand intermediate frequency tuning in .heterodyne and positive grid biaa in all sets. ity range: Model G-l .00002 to .0001 Model G-5 .0001 to 0005 MFD. Mode I PriceSl.SO ti'Post thumb, insert wire, 7ire is firmly held. Price 15c. Also furnished seven to a strip. Nicely marked in white with seven standard markings. Price $1.50 FREE Wiring Diagrams showing use in most popula sent on request. Write today. X-L RADIO LABORATORIES 2424 N. Lincoln Ave. Chicago, HI. Releases instantly us m •?>>' builders, you will want this a book on Camfield's Super-Sell /e Nine the greatest receiver e'er built. The wonder of the season. Big profits are in s 'or you. Send 25c today— no\ "AMFIELD RADIO MFG. CO. 161 E. Ohio St., Chicago, III Transparent Steel Recently Obtained THIN sheet-steel, as transparent as the clearest glass, has been recently obtained by a German physicist. This new method of making sheets of metal of unprecedented thinness seems likely to prove of farreaching industrial as well as scientific importance. Test plates, such as are used to determine the transparency of optical glass, and which were ruled with cross-lines 2500 to the square inch, were photographed thru such a metal sheet and, when enlarged to 400 diameters, the scale lines showed distinctly with no trace of distortion. This absence of aberration proves conclusively that the structure of the film was perfectly even and equal in all directions. The delicate sheets are made by depositing an extremely fine film of the metal on a smooth surface by means of an electric current, then separating the film from the foundation on which it is fixed. The metal film or sheets are so thin that atoms will penetrate them without impediment, yet so strong that when fastened in a frame they may be bent by blowing to the extent of one-sixteenth of an inch without rupture. Such sheets will have an important place in many kinds of scientific and industrial research since they may be used as membranes for the separtaion of gases, or lend themselves to the progress of television and telephotography. PETER J. M. CLUTE. A Time-Saving Hay Rack This hay rack was built with the end against the barn so it could be filled directly from the mow. A fence runs close to the outer end, yet there is room enough to fill the rack from a wagon rack during the summer. The particular advantage, however, lies in the fact that during the winter months it is not necessary to hitch up a team, throw the hay onto the hay rack and haul it to this rack. Instead hay can be thrown down from the mow and out the side door and into the rack, as needed Lowest Priced QUALITY "B" Eliminator Outstanding quality confirmed by lasting good performance on over 50,000 sets. The following interesting endorsements are but a few out of thousands — but actually your best means of verifying our claim of "singular value" in the good Ferbend "B" Eliminator. FROM MELROSE, MASS. If radio fans only knew the wonderful kick that can be obtained from your Eliminator, they would'nt waste anv more money on "B" Batteries.—C. S. Merrill. RICHMOND, VA. Your Eliminator has got it all over any that I ever used and I tried several different makes costing much more. — Wm. H. Bryant. DULUTH, MINN. I have used your Eliminator for over a year and it is one of the best investments I ever made.— L. W. Peters. NILES, OHIO The Eliminator I purchased from you a year ago has given results that could not be surpassed regardless of price. I have logged KFI, KGC, KFON,CZE,and6 KW.— F .I.McGuirk. Original cost less than half of any equipment of sini lar qu ali ty; low est main tenance cost Model Ill, for all set. using 90 Volts. $ 12 .50 Model IV, for extremely large sets and sets using power tubes; delivers up to 180 Volts, 50-60 Cycle, A. C— $17.50. MONEY BACK GUARANTEE _ m . not only in opera ECfUal tO Any tion, but in workmanship, quality, durability and appearance. Sooner or later you will change to "B" Socket Power. Why pay more? Approved and passed by the rigid laboratory tests of Radio News and Popular Radio. See your Dealer — or Send Direct Shipment made direct on receipt of price, or C. O. D. if preferred. Use for 10 days to convince yourself — if unsatisfactory write us within that time and purchase price will be refunded. Send Coupon TODAY. FERBEND ELECTRIC COMPANY 43 1 W. Superior Street Chicago, Illinois s'FERBEND — B ELIMINATOR /P FERBEND ELECTRIC CO. { 431 W. Superior St., Chicago, 111. ( ) Send $12.50 model. ( ) Send $17.50 model. ( ) Send at once. Payment enclosed. ( ) SendC. O. D. ( ) Send Literature. Name. . . Address. UjCity.... -J