[AMRadio] power ratings

Brett gazdzinski Brett.gazdzinski at mci.com
Mon Jul 11 12:18:35 EDT 2005

SSB amps make poor AM amps, partly because they are built for the very small
power output/duty cycle.

I would say AL-811 is good for about 100 watts carrier output tube wise,
but the power supply may not be up for it.
Many amps of that type use voltage doubler or tripler circuits,
and stiff regulation is not their strong point.

A pair of 3-500z tubes will do 400 watts of carrier I think, if the power
can handle it, and with fans, and with a 220 volt feed....

Seems quite silly when you can get 700 watts of carrier out of a pair
of 813's.
Or 300 watts carrier out of a pair of plate modulated 811a's.

If you want to get any clean power out, you likely have to run the rice box
at 15 or 20 watts so you don't get into the ALC stuff, and would need to
for an amp that takes less power to drive.

>From 25 to 100 watts is a big jump, even if 100 watts does not sound like a

I think 100 watts is qrp for AM, unless you work 40 meters in the day, with
a good

On the other hand, the rice boxes make great exciters for class C rf decks!


-----Original Message-----
From: amradio-bounces at mailman.qth.net
[mailto:amradio-bounces at mailman.qth.net] On Behalf Of zuu6k at juno.com
Sent: Monday, July 11, 2005 11:55 AM
To: amradio at mailman.qth.net
Subject: [AMRadio] power ratings

I thought I understood these things, But I have confused me little self.
I need some clear thinking here. I have a rice box rated for 100 watts
SSB or 25 Watts AM. I believe the 100 watts is PEP while the 25 watts is
RMS (continuous carrier). I want to add a linear amplifier to bring the
25 watts AM up considerably. I see the Ameritron AL-811 is rated for 600
watts SSB and 400 watts AM. Is this 400 watts PEP or RMS. If PEP that
means the RMS rating is 100 watts, the same as my DX-100. Also it
requires 75 watts of drive. Is this PEP or RMS. If RMS my rice box at 25
watts won't drive it. I am thinking the 75 watts of drive is PEP and my
rice box with 100 watts PEP in AM will drive it. Can someone clarify this
for me? Thanks.

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