Category: Magazines

On the Cover The inner structure of the ill-fated 6AE4 magnetron In this issue

On the Cover The Eimac XM15 developmental power triode, ca 1947 In this issue

On the Cover The NT57T Silica Valve In this issue

On the Cover When did you last see an LRS Relay, let alone two in the same room? 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 A Western Electric 240A with the radiator and anode cut away to show internal construction. Note that the water inlet and oulet fittings are displaced from each other, presumably to induce a spiral flow of the colling water. Photo from the late Bell Labs Historical Museum. In this issue

On the Cover The Eimac X-O from early 1942, first of a numbered line of “X” developmenta types that eventually ran into the low thousands, and one of the umpteen possibilities that eventually yielded the 527 radar triode. It appears to use th eduel stacked anode assembly and grids from the VT-158 Zahl tube, in...

On the Cover A bit of De Forest Radio Co. art from ca. 1931. It appears to be allegorical: the young Lee De Forest, being inspired to invent his Flame Audion, and the resulting, perfected S-bulbed triode. Of course, this month marks the 100th anniversary of successful tests of the first vacuum audions. In this...

Front Cover, Rear Cover Upper, & Rear Cover Lower Just Qvistad, LA9DL, and part of his tube collection. Various European receiving Tubes. The front row has the Lorenz DF41W at left, and a group of rare RFT (East German) miniature “gnome” types: EAA171, UCH171, UB171, etc. Rear row: three Loewe multi-unit tubes at left, two...