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[TenTec] Transmatches/Tuners/Etc.

To: <tentec@contesting.com>
Subject: [TenTec] Transmatches/Tuners/Etc.
From: n4lq@iglou.com (Steve Ellington)
Date: Fri, 19 Sep 1997 19:11:14 -0400
>   It does not really "tune"the antenna

This statement needs a comment. An antenner tuner does in fact tune the
antenna. Consider a typical dipole fed with open wire feeders (ladder
line). The tuner does in fact bring the entire antenna system, dipole
and feeder, into resonance which constitutes "tuning" the antenna.The
next job of the tuner is to match the resulting impedance of the tuned
system to the transmitter.

The reason for tuning your antenna system in the first place is to
eliminate reactance and provide a resistive load to the transmitter. For
example: Take a G5RV which is a 100ft dipole fed with some combination
of open line and coax. Without divine intervention, this mess isn't
resonant on any hamband except maybe 20 meters. The tuner will provide
the necessary values of inductance and capacitance to resonate the
entire system AND match it to the rig. TENTEC of course. I didn't want
to get off topic here!

Obviously, when we resonate the entire antenna system instead of just
the antenna, we must accept the additional losses in the feed line due
to standing waves which cause high current and voltage points along the
line. This is the big drawback to the so-called G5RV because we do have
substancial loss in that coax. I know that 3db doesn't sound like much
but when we run 1000 watts with our TITANS and loose 500 watts in the
system something is going to get hot!

Steve N4LQ

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