[CQ-Contest] Stack Matching/WX0B Stackmatch
Chad Kurszewski WE9V
kurscj at oampc12.csg.mot.com
Tue Jun 10 11:52:06 EDT 1997
With the fall of W9JA's (ex-KS9K) 15M tower, rebuild is in process.
I also am planning on rebuilding the stack match box, but am wondering
about the purchase of a WX0B Stackmatch.
My present design always uses at least one quarter-wavelength line to
assure a constant feedline length regardless of what antenna/combination
is selected. (This "ensures" operation in the same part of the Smith
Chart, thereby not requiring amplifier re-tuning for different antenna
selections. If the quarter-wavelength line is switched out, you would
be operating in the opposite part of the Smith Chart.)
I have a few questions for the owners of WX0B Stackmatches:
1) Other than the fact that the transformer doesn't do a perfect match
for the stack combinations, has anyone noticed amplifier mis-matches
when switching to a single antenna? (Or is that the beauty of a
transmission line transformer?)
2) Has the shifted SWR curves caused anyone any problems?
Ant.Impedance (ohms) 25 100
Single Ant SWR 2.00:1 2.00:1
2-stack WX0B SWR 1.77:1 2.25:1
3-stack WX0B SWR 2.67:1 1.50:1
3) Any reliability issues?
4) Anything else I should know?
Chad Kurszewski, WE9V e-mail: Chad_Kurszewski at csg.mot.com
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