I haven't had lots of different tuners to compare myself, but I do have
a Johnson KW Matchbox tuner. It does a great job on Balanced lines. I
didn't really know about the Palastar but just checked it out on the
website. Looked like an interesting tuner. But to me the downside of it
was that there is a balun on the output, which of course as Don stated is
a dominating factor in losses in a tuner (at least maybe that is what I
took away from his comments as well as other discussions on this subject
in the past). Is there a modern tuner out there for balanced lines that
doesn't use a balun?
I don't know of any. There is nothing wrong with using a balun as long as
the balun is looking into a relatively low SWR . The baluns we are all
familiar with only work well when feeding a balanced load that is fairly
flat. In other words the balun ought to be at the INPUT of the tuner
instead of the OUTPUT. This makes the tuner electrically and mechanically
much more complex and expensive and that is why you don't see it done very
often. As John said .. half a db or so does not matter as far as signal
strength at the receiving station is concerned. The only problem is that
the power dissipation could damage the tuner or balun itself at the
transmitting station.
As a purist with lots of time on my hands I am trying for the best of all
worlds by building a true balanced L-C-L tuner with a balun at the input.
It is an auto tuner with all of the bells and whistles and will (probably ..
I think) handle up to 500 watts into my big wire antenna (but probably not
into shorter antennas). I am going to put it into a K2 case with matching
button switches and a similar LCD. It is working now on the benchtop at low
power levels but it remains to be seen if, when packed tightly into a small
case, I can keep the PIC controller circuits sufficiently free of rf
interference at high power levels.
Don K7FJ
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