Hi John,
There is nice little 1954 paperback from CQ that precedes Stoner's book,
which the latter borrowed heavily from when he wrote his "New Sideband
Handbook"...I believe it's called "Single Sideband Techniques".
I have it downstairs in my radio library, & yes, it is probably THE
definitive article I've yet found re. the use of the 304 tube in a
grid-driven RF power amplifier.
~73!~ Eddy VE3CUI - VE3XZ
************************************
----- Original Message -----
From: "John Lyles" <jtml@losalamos.com>
To: <amps@contesting.com>
Sent: Monday, September 07, 2009 10:37 AM
Subject: [Amps] 304TH, 304TL, 813
> I picked up an old copy of Don Stoner's (W6TNS) New Sideband Handbook,
> dated 1958, CQ Technical Series, at a hamfest last month. Interesting
> reading, the Heathkit SB10 adapter was hot stuff then, along with the
> Central Electronic 10B and lots of Command set conversions.
>
> The amplifier chapter is fun reading. There is a section on using
> surplus tubes, such as the 304TL and the Western Electric 701A radar
> pulse tube on the low bands. For the TL in GRID Driven application, the
> drive power is said to be 15-20 watts PEP for 550 watts output. It has a
> step up input resonant circuit and a link coupled output with split
> stator cap. Classic stuff! The book has excellent references in each
> chapter, with a footnote pointing to Leary's article in Jan. 1955 QST,
> "Grounded Grid and the 304TH".
>
> An interesting section includes grid-driven 813 amplifiers using a clamp
> tube such as 6L6 or 6Y6 on the screen, the ZL1AAX and G2MA amplifiers.
> This stuff seems to have gone away for the most part, along with the
> need for neutralization circuits. Stoner wrote that 813 could take up to
> 3000 VDC with adequate bias voltage.
>
> 73
> John
> K5PRO
>
>
> >> Sent: Saturday, September 05, 2009 5:32 PM
> >> To: amps@contesting.com
> >> Subject: [Amps] The H&K 304H
> >>
> >> 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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