On the Cover A pre-prototype leading to the Eimac 304T, from an affidavit filed by Ronald H. Gordon, laboratory glassblower. He certified having made the tube “before1940.” The objective was to contest, successfully, a claim of inventing a “plurality of grids in an envelope” in a patent application by Harold Zahl of the Signal Corps....
On the Covers Two halves of a composite four-tube photo, from the De Forest Radio Co. A 10-1/2 X 19-1/2 print of this image turned up in the recent Boyer Estate auction conducted by the CC-AWA group. This is quasi-historic stuff: spired article in Raadio News, May, 1930. In this issue
On the Cover A reproduction of De Forest catalog art: images of the 500 and 504A triodes. The artist’s originals can be yours, via the CC-AWA auction planned for March. See p. 1 for details. In this issue
On the Cover The Eimac X-4 developmental triode of June, 1942; one of many versions that finally led to the 527 radar tube. The anode is from the 250T. Filament drain is 7.5v@30A. In this issue
On the Cover The RCA VHF receiving tetrode of 1935. See editorial page for details. Photo: Boyer Estate, courtesy of Robert Lozier. Drawing: RCA Standardizing Notice 3-1-839, in Dowd-RCA Archive, a holding of the AWA Museum.
On the Cover The beginning of a product line: William Housekeeper of the Western Electric Co. enginneering staff holding a 100-kW developmental tube made with the knife-edge copper-to-glass seal that he had patanted in 1919. In this issue