[TenTec] CFO? + cheap multiband vertical
Rob Atkinson, K5UJ
Wed, 04 Sep 2002 17:31:47 +0000
>Any good CFO squawks on 40m?
Chief Financial Officer?
For a cheap multiband vertical with no radials, try this:
Make a wire dipole, each side at least 20' long (or 5 or 10 feet longer if
you can) and hang it from a tree, or any nonmetalic support available. You
can make a support by using sandwiched overlapping 2x4s with a little
guying. Put a short plank at the top to hang the dipole off of. At the
feedpoint attach open wire feed or ladder line and run that away at 90
degrees from the dipole to a balanced transmatch in the shack. Tie down the
bottom so it doesn't flap around. As a vertical this will work well I think
and be useable over a wide range of frequencies (determined by the inductors
and capacitor you use in the balanced feedline tuner).
Okay, there's no free lunch and while the antenna is cheap, if you don't
already have the tuner, that will cost some money for the components,
especially if you are building or buying one for 1.5 kw.
OTOH, you'll have an addition to your shack that you will be able to use on
all kinds of antennas fed with open wire line. The key here is using a
_balanced_ transmatch, sort of two synchonized LCs, one on each leg of the
feedline sharing a capacitor with a balun between them and the transmitter.
Keep the antenna simple; let the matching network do the work. See:
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