Steve Ellington wrote:
>
> >
>
> I believe that most MFJ tuners use the T network and TenTec uses a
> swtichable L network. L networks are know for their low loss while the
> losses in T networks can be quite high.
We're getting into an area I don't know about- I thought the MFJ used
the
same circuit the ARRL handbooks show as the SPC transmatch, known as the
PI network? Go ahead, I'm learning!
> Once a match is finally made by juggling the knobs and dials, the
> settings can be recorded for future use.
Yes, this is true, but the roller inductor action in my Ten Tec 229B
tuner
has so much backlash (with respect to the linear scale) that it's
difficult
to reproduce exact inductances. The numbers around the dial are more
accurate,
but don't make up for the inaccuracies of the linear scale. If you've
ever
used a REAL turns counter, you'll understand what I'm talking about. One
other point to make: the MFJ turns counter is JUST AS JUNKY as Ten
Tec's.
My point was that for almost $400, why couldn't Ten Tec put in a real
turns
counter? Modern radios got away from linear scales for a reason- they're
difficult to interpret precisely.
> The balun used in the MFJ is also inferior to TenTec's.
This is probably true. It's been years since I've been inside either, so
I
can't make an educated comment. I prefer glass-fiber-tape covered,
teflon-insulated-wire toroids for tuner baluns. I don't know what either
Ten Tec or MFJ is using.
> Keep in mind that an "easy match" may be a lossy match.
I won't argue with that, but my signal reports don't bear out that my
matches were lossy with either tuner.
> Perhaps pruning the feeder or antenna to make the match easier
> would result in lower tuner power loss.
I'm using a 75m Delta Loop on all bands, so the feeder length is
basically
irrelevant. Loss isn't my problem, the difficulty in determining the
correct
"LO" or "HIGH" value of capacitance to match a given frequency is. Sure,
I
could use resonant antennas, then I wouldn't need a tuner! The purpose
of a
tuner is not to match resonant antennas, it's to match NON-resonant
antennas.
One other thing I didn't mention is that the trees I'm using for support
tend to sway in the wind and grow new leaves. As large as my antenna is,
and
because of it's configuration, this causes appreciable changes in
impedance,
and any particular condition of the antenna is not reproducible from
day-to-day.
No, a Millen type turns counter would NOT improve this condition. My
situation
dictates different tuner settings on an almost daily basis! Now if I
could just cut those trees down, and replace them with telephone
poles.....
> N4LQ Steve
73 Steve, we'll have to chat on the air sometime. -Web
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