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...
On the Cover Some “unborn” Kellogg AC tubes. As Alan Douglass describes them: A Friend just presented me with a cigar box containing these four specimens, along with poop sheets for the McCullough and Kellogg tubes. Evidently someone toured the plant and fished souvenirs from the scrap barrel. These look earlier than any finished tubes...
On the Cover “Life tests on continous evacuation of 304TL / March 8, 1943” Shows impromptu test rig at Eimac’s Salt Lake City plant. Subject: 304TL triode is at upper center of photo, attached to a vacuum manifold atop an oil diffusion pump. An ion-guage tube is on the same manifold, to the left. A...
On the Cover The “Liberty Valve” as once sold by the Radio Apparatus Co. of Pottstown, Pa In this issue
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
The RCA “Selling Fool” doll, a retailer display aid designed ca. 1926 by the major cover/commercial artist Maxfield Parrish. The “Fool” replaced the “Radiotron Man” figure as seen on the Feb. cover, although Web postings about the doll often use the “Radiotron” name. RCA’s $5 price for a quqetet of dolls is ironic – this...
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.
Some thermionic jollity for the season, courtesy of Bengt Svensson In this issue