Many thanks to all who took the time to respond to my query about the old
Heintz & Kaufmann 304H (their version of the Eimac 304TH, per Lud's note to
me)...
Well, research into my radio shack library here revealed that the 304H is most
certainly NOT a good candidate for grounded-grid service: a piece in a 1954(?)
issue of QST described just such an arrangement, & stated that for a kilowatt
(approx.) input, a single g-g 304H would need 120-watts of drive!
Hardly promising.
However, I did take heart when thumbing through my 1980 edition of the ARRL
HANDBOOK: there's an interesting low-band "junker" design listed therein that
incorporates a grid-driven 833A. The article makes mention of the possibility
of using a 304TH in its stead, & published specs say that such an arrangement
would need but 30, or so, watts of drive...ideal.
As I mentioned to Lud, I could lash together a robust enough filament voltage
provider that would easily power up either an 833A, or a 304H: then, with the
filament "sockets" paralleled, and allowances made for room, I could run either
tube in the circuit, as dictated by availability & interest...
...One tube at a time, of course!
~73~ Eddy VE3CUI - VE3XZ
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