Cage elements basically make a large diameter element, which increases the
bandwidth (which is largely determined by the length/diameter ratio).
Nothing special or exotic about them. You need some sort of spreader to hold
the wires apart. If you've got lots of wire around, it's a great idea.
Indeed, the "resonant length" will be different from a single wire. You
could probably do something where most of hte antenna is a cage and it has a
stub on the end that's a single wire you tune, although that might have
some problems (probably, you'd be better off with the stubs in the middle..
you'd more closely approximate a conical element, which has very wide
bandwidth (think discone)).
The trick will be in the mechanical aspects. If the "overall diameter" of
the cage changes, the resonant frequency will change, so you''ve got to give
some thought to the spreaders. You can also just spread it in one
dimension, rather than putting them in a circle. Think of those UHF bowtie
antennas that clip on the back of the TV, or which are in front of a corner
reflector.
----- Original Message -----
From: "Eugene Jensen" <eugenejensen@nyc.rr.com>
To: <towertalk@contesting.com>
Sent: Sunday, September 19, 2004 7:48 PM
Subject: [TowerTalk] 80 Meter Cage Antenna
> I have just moved to a new QTH this past summer and it is too late into
our
> season to reinstall my crank up towers. The new QTH has a couple of
rather
> large tall trees and being an electrician, and different gauges of wire
> being in abundant supply -- building the cage out of 10 ga. or 12 ga. THHN
> insulated wire other than maybe changing the length of the antenna
> somewhat -- any other pitfalls that someone could elaborate for me would
be
> very helpful. The other thing -- studying the antenna book -- it appears
> that all you are doing is basically soldering the four wires in parallel
and
> then just adding a one-to-one coax balun at one end. I understand that it
> would be somewhat heavy but again, it only has to last the winter and I
> could get it up about 75 or 80 feet off the ground. I appreciate any
> advice. Thanks in advance. Gene K2QWD
>
>
> _______________________________________________
>
> See: http://www.mscomputer.com for "Self Supporting Towers", "Wireless
Weather Stations", and lot's more. Call Toll Free, 1-800-333-9041 with any
questions and ask for Sherman, W2FLA.
>
> _______________________________________________
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> TowerTalk@contesting.com
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_______________________________________________
See: http://www.mscomputer.com for "Self Supporting Towers", "Wireless Weather
Stations", and lot's more. Call Toll Free, 1-800-333-9041 with any questions
and ask for Sherman, W2FLA.
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