Topband: INV L questions

Roy Koeppe royanjoy at
Mon Nov 20 12:46:46 EST 2006


"...Second suggestion was use 234/f and match with an inductor across
feed to ground. I can't find dimensions for this, however. What is
the preferred matching method for those on-list who are using Ls?

I will get you into the ballpark for the shunt, or inductive match. The
coil can 'start out' with about 6-turns on a 2-inch diameter form,
spaced wound to cover a 2-inch length. Not critical, and 14-gauge wire
is fine). After you install the shunt coil to ground, the antenna will
resonate slightly lower in frequency. (The coil provides for handy
coupling into a grid-dipper). Now you will juggle things, shortening the
antenna element for proper resonance, while adjusting the number of
shunt turns for a perfect unity SWR. Some cussing will probably
help--but after you achieve the balance between resonace and 1 to 1 SWR
everything will be worth it. The shunt matching inductor provides you
with a DC earth ground for the antenna which is desireable. Plus it's
virtually free.

73,   Roy    K6XK    Iowa

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