[AMRadio] AM Usage with Linear AMPS

Ed Swynar gswynar at durham.net
Mon Nov 22 08:03:16 EST 2004


A good rule of thumb to follow is simply this: the maximum carrier output
you're going to safely get out of your separate linear amplifier is limited
to HALF of the plate dissipation of your linear's tube(s)...

Example: I sometimes drive my HB 2 x 813 as a linear for AM. Each tube has a
plate dissipation of 125-watts. HALF of that is 62.5-watts, so with 2 tubes,
it'll be 125-watts carrier output MAXIMUM.

I adjust my drive to the linear, watching the output power meter, until
125-watts is achieved. I might "tweak" the plate tuning capacitor after this
is done. It takes some 10-12 watts of AM to get 125-watts out of the 813s.
When speaking into the mic, I always watch the trapezoidal pattern on my
SB-610 'scope, & make sure I have enough audio.

Hope this helps!

~73~ Eddy VE3CUI - VE3XZ

----- Original Message -----
From: "Ralph Daniels" <rbdaniels at msn.com>
To: <amradio at mailman.qth.net>
Sent: Monday, November 22, 2004 7:54 AM
Subject: [AMRadio] AM Usage with Linear AMPS

> Hi all,
> I feel this subject must have been covered many times but I just can't
find it.
> Specifically, I have a Heathkit HX-10 Marauder driving an Ameritron
> on CW and SSB and would also like to try it on AM. The driving power on AM
> is 25 watts.
> Is this a correct use of the amplifuer and if so what are some operationa
> guidelines as regards i/p and o/p power, duty cycle, cooling etc.
> Thanks in advance,
> Ralph Daniels, N1SK
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