QST . The Big Six of Amateur Radio: 4-65A,4-r25A, 4-250A, 4-400A, 4X150A, 4E27A ^^ Whats New with the Electron, a brochure distributed at the I.R.E.show discussing Eimac tube developments of the
Handbook of Amateur Tube Uses : Raytheon Production Corp. : Free Download, Borrow, and Streaming : Internet Archive