Category: Magazines

On the Cover The Eimac X-1, a developmental triode from May, 1942, using the bulb and base of a 250T, with new anode and heavier filament taking 25 anps instead of 10.5. In this issue

Hisashi Ohtsuka (right), enjoying his 2009 Schrader Award plaque with Dr Yukawa, museum director of the University of Electro_Communicationon Tokyo. Photos: Hisashi Ohtsuka   In this issue

On the Cover Eduard Willi, Swiss tube-history author (see p. 2, depicted with a Signum G 2 H 34 rectifier. In this issue

The mount drawing for the now-eBaygenic “single-plate” 2A3 audio triode, with its 20 filaments. This original version carried a reputation for being hard to amke in terms of equal tension on the filaments, and was soon superseded by new designs. The note about the tensioning springs testifies to this diffuculty. Image: RCA Standardizing Notice 3-1-2A3,...

On the Cover The vanishingly rare GL-8009, a version of the 880 triode with two extra posts for the grid leads, introduced by GE in 1942. While “intended for television service’ on prewar tv channels, its frequency rating for full power was no more than that of the 880, or 25 MHz. In this issue

On the Cover The Eitel_McCoullough 4-250A tetrode of 1948. In this issue

On the Cover The Eitel-McCullough X-7 triode of mid-1942, one of many exploratory designs that eventually yielded the 527 radar tube. In this issue

On the Cover The base-branding machine in the De Forest Radio Co. plant, ca. 1929. The five-pin basses rotate into contact with the branding die – the white object at lower center above the pipe elbow. Heated by a gas flame just below, it burns the De Forest script logo into the base. In this...

The Western Electric 7C22, a packaged push-pull radar oscilator. See story on p. 16   In this issue

Daniel Stocks, Australian microwave-tube expert, left visits Ron Lawrence and his “Radio Heaven” display in North Carolina. Photo: Robert Lozier.   In this issue