That doesn't sound like the Palstar tuner I have. Mine is the "classic"
balanced L network using 2 roller inductors linked by a drive belt and
with a choke balun on the TX side of the network. But...
.... mine has nothing like the matching range of the 238. The Palstar
fails to match my 132ft doublet at the bottom end of 80m, and doesn't
get close on 160m; nor does it have the clever arrangement in the 238
for switching in the small value C to form a Pi network. Of course I
could just be unlucky with the feeder lengths. The Palstar is now
sitting back in its cardboard box and the 238 has pride of place. I'll
accept whatever problems the 238's balun might cause!
73,
Steve G3TXQ
Rob Atkinson wrote:
> As someone else wrote, take a look at the Rich Measures article.
> http://www.somis.org/bbat.html
>
> The price of the Palstar isn't too bad for what you get; I think it's around
> the price of a new 238B. But you can make one--it's not too difficult to
> do, especially if you don't need a lot of power handling capability. I
> don't think the MFJ parallel wire feedline tuner is what I consider a
> genuine balanced tuner. I took a look at the schematic of it when it came
> out and I recall not liking what I saw, but can't recall the details. Don't
> hold me to this but I think it involved 2 or 3 caps and a switched tap
> inductor in some scheme that might transform the balanced Z to 50 ohms, but
> wasn't balanced itself. OTOH, it might work FB for ur power levels. BTW,
> MFJ may have come out with better models since then. I would consider the
> homebrew route myself.
>
> 73
>
> rob / k5uj
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