|[AMRadio] AM Transmitter Advice??|
bbruhns at erols.com
Fri Feb 17 11:23:27 EST 2006
12AX7s have surprised me with their power
capabilities before, but 20 watts output with 30
watts input is 67% efficiency, and that means that
the 20 watts output is the PEP output of the
3-12AX7 linear. I think that the 10W rating with
a 6AG7 is PEP as well.
----- Original Message -----
From: "Jim Candela" <jcandela at prodigy.net>
To: "Discussion of AM Radio"
<amradio at mailman.qth.net>
Sent: Friday, February 17, 2006 7:29 AM
Subject: RE: [AMRadio] AM Transmitter Advice??
> Hi All,
> I recently had a conversation with a ham in
> Antonio (forgot his call), and he told me that
> built a unique linear amplifier for his central
> electronics 10a, and for tubes he chose 3 type
> in parallel grounded grid. He said he could run
> watts input (300v @ 100ma) with no problems, and
> 20 watts out. I find it odd though that a 10a
> 10 watts with a single 6AG7, and 20 watts is
> 3db boost.
> To my way of thinking, a linear amp needs to
> your power at least 6 db (~1 'S' unit) to be
> trouble. For us AM'ers, going from 100 watts to
> watts carrier does not meet the 6 db boost
> and that explains why a good antenna on a DX-100
> better than a average antenna on a Globe King
> Still, as I once posted last year, a dual 304TL
> grounded grid linear seems to fit the bill as a
> 'brick' capable of 400 watts AM carrier output
> 100 watts AM input, or said another way it takes
> watts PEP and boosts it to 1600 watts PEP. There
> an old W6SAI construction project about this
> 304tl GG amp), and I recall that the setup in
> could run 1 kw dc input with over 1 kw rf output
> because of the low gain, and massive amount of
> feedthrough power from the exciter that finds
> to the output. This was a way around the FCC
> rules of the day.
> --- Donald Chester <k4kyv at hotmail.com> wrote:
> > >Assuming one is going to build a linear, and
> > putting aside other issues
> > >such as linear vs plate modulation, why do
> > think it makes a difference
> > >what tube is used? Are you referring to
> > linear at greater than
> > >legal limit?.
> > Well, go ahead and try building a legal limit
> > that runs a pair of
> > 807's in the final.
> > This message was typed using the DVORAK
> > layout. Try it - you'll
> > like it.
> > http://www.mwbrooks.com/dvorak/
> > http://gigliwood.com/abcd/
> > AMRadio mailing list
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