Radio Broadcast (Nov. 1925-Apr 1926)

264 RADIO BROADCAST ADVERTISER DIAMOND-WEAVE (TRADE-MARK REGISTERED Aug. 4, 1925) SICKLES COILS For the "Aristocrat," Browning-Drake, Roberts, Craig, and Hoyt Circuits (Patented Aug. 21, 1923) Our Coil Set No. 25 is specifically designed for the new "Aristocrat" Circuit, already very popular. Compactness of form, rigidity of construction, and the supremely efficient Diamond-Weave method of winding are well-known characteristics of Sickles Coils. These refinements of design and construction result in low distributed capacity, low dielectric losses and large range of frequency with small variable capacity. There are Sickles Diamond Weave Coils for all leading circuits. Sickles Coil Set No 18A for Roberts Circuit. $8.00 per set. Sickles Coils for the "Aristocrat" Circuit, designed upon new scientific discoveries, set highest standards of efficiency. COIL PRICES No. 18A Roberts Circuit No. 24 Browning-Drake Craig Circuit Acme Reflex Knockout Reflex Hoyt Circuit "Aristocrat" Circuit No. No. No. No, No. 20 19 8 21 25 $ 8.00 set 7.50 set 4.50 set 4.50 set 4.00 set 10.00 set 8.00 set Send for descriptive catalog The F. W. Sickles Co. 132 Union Street SPRINGFIELD, MASS. The Hit of the Show 99 At the recent Radio Shows in New York — wherever it has been shown or demonstrated— the Furnell Taper Coil Condenser aroused a veritable furore of interest. Mechanically and electrically, professionals claim that the Furnell offers in the simplest, most practical form, the correct solution of the straightline frequency problem. By the use of the Furnell Condenser, the crowding of low-wave stations is entirely done away with. Regardless of wavelength, all stations are tuned in with remarkable ease and clarity, over a complete revolution of the 360 ° dial, furnished with each condenser. Write for Literature No matter what type or model you build, buy, or sell, you can't know its best performance until you use this wonderfully improved type of condenser. In three capacities, single and multiple. THE FURNELL MANUFACTURING CORP. 24L Scott St. Newark, N. J. Only two plates are used, each plate being in the form of an evolute coil, like an unwound clock spring. The rotor coil is tapered and made to mesh and align perfectly with the stator coil, through a sliding motion, on a spiral worm rotor shaft. The unique method of meshing the rotor and stator coils, affords a wonderful smoothness of operation and a precision in tuning, impossible with the old type of condenser, while it eliminates all necessity for a vernier. And to insure its permanent accuracy and precision, the Furnell Condenser is entirely enclosed in an attractive, strong, transparent Pyralin case. This shield insures absolute protection against dust, moisture and damage. FURNELL 360° TAPER COIL CONDENSERS Do It Yourself — It's Easy Manufacturers FLASH tubes during the process of building them. In doing so, they boil out the thorium with which the filament is impregnated and deposit it on the surface. This permits the filament to function at less heat and less A'battery consumption than when a tungsten filament alone is used — as with the old style tubes. As the tube is used in the set, the thorium coating gradu' ally drops away. FLASHING will boil out some more the rium to the surface of the filament and bring the tube back as good as new. YOU CAN DO IT YOURSELF WITH A FL/ASHE.R Send for pamphlet "Save a Life" Burton & Rogers Mfg. Co. 755 Boylston Street, Boston, Mass. 400 CENTS RESISTANCE is the subscription price to Radio Broadcast for one year. This is less than the cost of a good low loss variable condenser. Let us enter your subscription to begin with the next issue. Send $4.00 with your name and address to Radio Broadcast, Garden City, N. Y. ■k Tested and approved by Radio Broadcast ir