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Old September 2nd 08, 07:16 PM posted to rec.radio.amateur.antenna
[email protected] nm5k@wt.net is offline
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First recorded activity by RadioBanter: Jul 2006
Posts: 757
Default Multi wavelength antenna

On Sep 2, 8:47*am, wrote:
Would it increase 'performance' or just cause problems? *Probably
both. *The performance increase may or may not be present when
compared to what you're using now. *Problems? *You can bet on it.
Mechanical ones mostly. *What conductor will you use that will hold up
it's own weight at 480 or 900 + feet? *And since there will be 'sag'
no matter what you use, will the end points be high enough to keep
from 'clothes-lining' yourself on the antenna? *Certainly not
impossible to put up such an antenna, but not exactly as simple as it
sounds.
*- 'Doc

Do it! *See what happens.


For that length, I imagine you would need multiple supports along
the way to deal with the sag. Of course, you could use real light
gauge
wire to reduce the tension needed to sag, but then the first real
storm that comes along and it will be most likely toast and he will
have to do it over again.
Unless there is a real need for the directive gain, I'd tend to avoid
the
real long wires.. Can be more trouble than they are worth, considering
I can use a yagi and be able to steer the thing at will. With a wire,
you are stuck with one or two directions, depending if terminated or
not.
I've considered running long wires as a beverage receiving antenna,
and even it can be prone to damage after a while with all the trees
whipping in storms, etc.
But at least the usual beverage is low to the ground, and fairly easy
to install and repair if needed.
Long wires can be interesting, but I would not want them as an
"everyday" antenna. I'd always have the standard dipoles, etc for
everyday use. I might play with a long wire, but it would be an
"extra"
antenna used more as an experiment.
Being there is no real efficiency advantage to using extended dipoles,
the only reason to really consider one is if you want some gain in
certain directions. Being that there will be directions where the
gain is less, and you can't control the pattern, any advantages
would be totally up to the user and who they work.
It would generally be a disadvantage to me on the lower bands.
I want to be as loud as possible in all directions..
I have used a few extended double zepps with good results, but
that's only .64 wave per leg. Or about 150 feet +- per leg of the
dipole. "about 300 feet total". Anything longer than that, and the
pattern becomes more X shaped, and the gain is no longer
broadside to the wire.
Anyway, to make a long story short, I would not use extended
dipoles if it were me building "everyday" use antennas.
I'd stick with the standard dipoles, etc, and leave the long wire
stuff as "experimental or DX" antennas. With that much room,
seems to me he could have both.