"Mark Keith" wrote in message
m...
"Thierry" To answer me in private use
http://www.astrosurf.com/lombry/post.htm wrote in message
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"Cecil Moore" wrote in message
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Thierry

I may be confused now after reading all the posts, but if you have a
good SWR on the rig that is driving an amp, this is normal, even with
a mismatch to the amp. The amp probably has a tuned input circuit.
It's not going to change much if any, if the SWR to the amp goes high.
Or I don't believe anyway...You should run a meter before the amp, on
the antenna side, to also measure the SWR to the amp. The meter in the
rig is just looking at the tuned input circuit of the amp. You need
another one if you want to keep the amp happy.

Is this really necessary Mark ?
My config is TX (+built-in ant.tuner and SWR) + AMP + SWR + antenna.
The TX antenna tuner can match the load upo to 2.5:1 to get SWR 1:1 on its
terminal, not further.
The AMP load/plate knob are tuned in the proper band in order to get the
lowest SWR (read on the external one, place just after him)
The SWR, the exernal one placed between the amp and ant, read, in my
opinion, the SWR towards the antenna, not toward the RTX conrrarily to what
state ARRL in its Q&A column.
You speak of inserting another SWR between rtx and amp ? why for ? I do not
understand its utility from the moment I can fine-tune the the amp with the
SWR placed just after it, toward the antenna (in practice in adjusting the
plate on the right band and then the load, in adjusting with accuracy this
latter the SWR increases or descreases). It enough.

NB. at the time of my tests all worked fine, my amp gave all its 850W
although much reduced due to high SWR 4 (I emitted about 300 W) and no one
rig was damaged. Of course I never worked longtime this way but I did some
SSB QSO (thus theoretically enough to burn something) and I had to tune my
RTX to reduce the SWR the best I could. Of course I do never suggest to
proceed this way to nobody but instead to find a solution to get the lowest
SWR (say below 2:1 or even 1:1 if you antenna permits).

Thierry
ON4SKY
http://www.astrosurf.com/lombry

A solid state amp is
much more critical than the tube amps as far as SWR. But I still
prefer to keep a tube amp under 2 to 1, unless I lower the power
level. But I've run 3:1 or worse many times with my henry 2K classic,
and it never complained. As long as you are within the loading range
of the amp, it's perfectly fine. I think the tubes do run a bit hotter
if the SWR is excessive. Thats why I'll drop the power a bit. When I
do run the amp, I almost always have a good match, IE: coax fed
dipoles, yagis, etc... and I almost never use a tuner. I haven't
actually run my amp in about 4 years. I have it dismantled, and have
been too lazy to order new caps and out it back together. I really
don't need it most of the time. It's handy if I want to brown the food
in a certain area.
MK