Date: Fri, 10 Feb 2017 17:52:14 -0600
From: Kevin <kstover@ac0h.net>
To: amps@contesting.com
Subject: Re: [Amps] PowerGenius XL Video
No way a pair or trio of 3-500Z's does 1500W FM/RTTY key down all day.
An 8877 won't do it either without having a very big, very loud blower.
R. Kevin Stover
AC0H
ARRL
FISTS #11993
SKCC #215
NAQCC #3441
## Art bell told me his cat fell asleep on the footswitch, while he was out
doing errands.
He comes back to his shack full of smoke, and the poor alpha 87-A had been
sitting there
on 10M FM, putting out 1.5 kw for 2-3 hrs non stop. He phones up alpha and
asks the
tech about the... no time limit spec. Tech tells him...not to believe the
advertising hype.
The PI-L had overheated and half come apart, amongst other things. But thats
a one off case.
## The power genius would indeed swap bands back and forth, using a single
flex xcvr, so it
will do SO2R, with just one amp..and one xcvr. Now that will work
...provided the swr
on each band is either flat, or very low. IF you had separate feedlines to
each ant, then at least
you could install a dedicated manual tuner in each feedline. If not, then an
automatic 2 kw rated
tuner is required. I have not seen any 2 kw rated automatic ant tuners that
will swap bands in
a split second. Provided the swr was ok, the power genius would save the
expense of a 2nd amp.
## Ill defer to Bill, as he is the rtty expert. Does the typ xcvr operate
fsk or afsk ? You might be
able to increase the bias on a tube amp, and lower the idle current way down,
when operating rtty.
Tank eff could be improved a little bit, reducing plate dissipation. If eff
was as high as say 70%
running increased bias, to get 1.5 kw out would require 2143 watts dc input =
643 watts anode diss,
which is well within the specs of even a pair of 3-500zs, never mind 3 of em.
## Loud amps can always be re-located to the workshop next door in my case,
but that is not always
feasible. It also requires running in there to tweak them, or change bands
etc.
Jim VE7RF
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