----- Original Message -----
From: "k7fm" <k7fm@teleport.com>
To: "jeremy-ca" <km1h@jeremy.mv.com>; <andy@gd0tep.com>; "'amps'"
<amps@contesting.com>
Sent: Wednesday, April 02, 2008 11:10 PM
Subject: Re: [Amps] 4pr1000 bias question
> "Thats 1200W idle current for AB2!
>
> Eimac recommends around 500-600W. Are you looking at the PP pair AM
> modulator spec?"
>
> I suppose the good news is that someone reads the stuff I write. I should
> waht I send out, since 1200 watts indeed exceeds the plate dissipation of
> the 4-1000. I can plead that I was simply a scrivener, reporting the
> facts typed out in the 1972 Radio Amateur's Handbook. There are
> footnotes, but none apply to the data quoted. So, nothing says two tubes,
> but it would have to be. However, with Carl's data and mine, it appears
> that the original question can be answered. Bias voltage should be
> around -60 volts and would then be set for 150 ma, which is the 600 watts
> Carl mentioned. The -200 volts on cw would be cutoff (or it could be
> higher) on standby.
>
> Less plate voltage will require less negative voltage to set the proper
> bias. Old tubes may require less negative voltage.
>
> Good catch Carl! Wonder why the ARRL is giving us data for a 3 KW
> modulator, and where is the 6 KW am rig construction article.
I would have buzzed right buy it except having built many one and two holers
for customers in the days good pulls were freebies 2 or 4 at a time from
local 5KW BCB rigs.
The 2 holer articles were in the W6SAI books until they got pressured to
stop.
Carl
KM1H
> 73, Colin K7FM
>
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