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Hi Scott,<br>
That is a really impressive project. Thanks for posting.<br>
73, George<br>
W2GS<br>
<br>
<div class="moz-cite-prefix">On 11/3/2020 9:31 PM, Scott Traurig
wrote:<br>
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<pre class="moz-quote-pre" wrap="">***** High Performance Software Defined Radio Discussion List *****
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<div>There are plenty of examples of how to do this. Building
the requisite coupler is not difficult. You can buy them from
Xtronic.</div>
<div><br>
</div>
<div>Here's a more relevant example: <a
href="https://digitalcommons.calpoly.edu/cgi/viewcontent.cgi?article=1191&context=eesp"
moz-do-not-send="true">https://digitalcommons.calpoly.edu/cgi/viewcontent.cgi?article=1191&context=eesp</a></div>
<div><br>
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<div>Incorporating something like a NanoVNA into this design,
and changing the software to calculate the required L and C
directly instead of iteratively should be possible.</div>
<div><br>
</div>
<div>This could also be accomplished using a link coupled
topology if you prefer.</div>
<div><br>
</div>
<div>73,</div>
<div><br>
</div>
<div>Scott/w-u-2-o</div>
<br>
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<div dir="ltr" class="gmail_attr">On Tue, Nov 3, 2020 at 2:38
PM <<a href="mailto:radio@netins.net"
moz-do-not-send="true">radio@netins.net</a>> wrote:<br>
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<div
style="font-size:10pt;font-family:Verdana,Geneva,sans-serif"><br>
Using SWR is done when tuning L networks, but would like
to try adding stepper motors to a Johnson Viking Matchbox
so I can use it.<br>
<br>
I can't seem to come up with a method to tune for minimum
SWR. I suppose one would adjust first the tuning and step
the loading one way or the other and use the low SWR
position to hold for the next iteration. Then repeat that
process over and over.<br>
<br>
I have been told it is quite difficult to make a
directional coupler that works well over the 160 - 6m
range, but a calibration file could be made at the antenna
system feed point (input side of Matchbox) that might get
a close enough calibration to use for tuning. <br>
<br>
John, W0GN<a
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rel="noreferrer" target="_blank"
style="font-family:Arial,Helvetica,sans-serif;font-size:small"
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