It most often depends on the electrical equivalent of the
antenna system. Sometimes only minor changes in the
antenna system allow a tuner to do it's job. Your best bet
is to configure the antenna with a higher radiation resistance
than 50 ohms instead of lower. Try different grounds,
different antenna lengths, different tuners.

Often a different tuner configuration will allow a match.
To expect a single tuner to handle infinite matching situations
is ludicrous. Read up on the subject. The ARRL antenna
manuals are rich in theory. Consider that there may be many
undefined matching situations where infinite current or voltage
may be placed in the tuner that would burn or arc.

I have a 300w MFJ tuner (T net) that I bought used for $40 and
an LDG kit tuner (Reversible L net). They work just fine when I
design the antenna so that impossible matches are avoided.
Although the LDG may tune a greater range, that also causes
it to find a greater number of impossible matches.

Jim, ac6tk

"Bob Miller" wrote in message
...
On Sun, 24 Apr 2005 11:10:53 -0400, Robert Myers

wrote:

Hi Steve,

Thanks for the information.
Good ground where, though? Around the antenna, like 'wires in the
lawn.'
Or, a good ground from your transmitter to ground, or good ground
from your SA-2040 to ground (or both via separate braids to a
common
ground point --- like a cold water pipe. Not too sure. Can you
elaborate?

How did you create your good ground? How about if I soldered a 5
ft.,
3/4 inch braid to the point where the cold water feed from the
city
enters the basement --- I can set up the whole station right in
that
location then (within that 5 feet I mean, because the basement is
unfinished. How are you doing your grounding?

Thanks for the help.
--- Rob

You may or may not need an RF ground, depending on whether you are
tuning a balanced or unbalanced antenna. I have 1/2" braid coming
off
the back of my mfj tuner to a short length of copper pipe (I have
rock
about 12" down), and then I have two 70-ft buried wires across the
lawn.

I'm still trying to decipher what constitutes a good or better
tuner.
I recently got an older Murch 2000 transmatch whose components, the
two variable caps and the variable inductor, are about 50% bigger
than
those in my mfj-989c, but the Mighty Fine Junk tunes bands the
Murch
won't touch :-)

Oh, well...

bob
k5qwg




Steve wrote:

Rob, got a 2040 also, mine has 28 uh roller inductor
in the middle and it hanldes extreme loads! Dont know
what your trying to tune, but have 2 loops here and its a
breeze to work with! sometimes a single wire antenna
poses a threat to the tuner. got a analyzer here and it
seems to tell the truth more often than not!
Key is a good ground, and is a must!

steve.... gud luck.