Hi Terry,
The X Match price is $1045, but I had to add $41 for Fed Ex
shiping to Kauai. I charged it to my Visa once I had the confirmation
from HRO that my account had been credited for the cancelled
order for the Nye tuner.
Well I guess I should have thought to save the e-mail replies.
But a brief summary is:
All of the commercial tuners available are fine for 20, 30,
and 40; they most begin to show limitations at 10, some at 15, and
at 160 meters. The problems are that all( except Ten Tec and
the X Match) use a Pi network, that is the capacitors are in series
with the signal, and the roller or tapped inductor, between the
two caps, runs to rf ground. The result is quite high Q which
means high reactances, which leads to high voltages across
the caps and coil turns at QRO, escpecially on 10 and 160
meters. The inductors used in all, including the Nye are too
small--turns too close, diamter too small. Some use pretty
rinky-dink mechanical linkages between knobs and cap and
inductor shafts, or even "home-made" ones as in the Nye,
Many have had trouble with just the mechanical assembly of
MFJ and even the Nye units, beside the rf voltage build up
problems at higher powers. The L-network of the Ten Tec
and X Match are by nature low reactance and therefor low Q.
Not only does this keep the standing voltages down across
the components if you are operating well away from anetnna
resonance, but it also allows lots more bandwidth of QSY
operation without having to constantly be twidling the tuner
knobs when running QRO.
I actually melted one end of the older style MFJ roller inductor of
a few year old 3 kW tuner of theirs one evening while working on
160 meters: too high reactance to get low vswr to the trasnmitter,
resuting in very high vswr on the transmission line, and a lot of
power heating the wire of the MFJ supposed 3 kW inductor. MFJ
now uses an air core inductor, but the wire of the inductor looks a
gauge smaller to me!
Dave Thompson, K4JRB, told me the cost of just the roller inductor
and the turns counter used in the X Match was about the same as
MFJ's price for their 3 kW tuner! It is a much larger, and heavier
inductor than that used in any of the others, and Paul Schrader, N4XM
who designed and builds the X Match did this unit emphasizing
its design use on 10, 80 and 160 meters. Of course Dave and Paul
are both very active in 160 contesting, so I am confident they know
whereof they speak, and believe that Paul's design will prove to be
very satisfying to me, though, of course, I have not even seen one
of the units as yet. But one day next week.........we'll have a look
inside, and shortly thereafter I'll have my 87A giving it a good shot
of Watts across all nine HF bands, and I will post the results and my opinions!
73, Jim,AH6NB
73 and Aloha,
Jim Reid, AH6NB (Happily retired on the Island of Kauai)
Hawaii, USA Email: jreid@aloha.net
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