On Tue, 1 Jan 2002 hasan schiers <schiers@netins.net> writes:
>
SNIP
>
> I've used the w9inn 160/80/40 sloper on a 72' tower with hf antennas
> above as a capacitive top load. On 160 the vast majority of the
current
> was in the tower. On 80, the tower still dominated, on 40 the wire
portion
> started to share the current distribution more equally.
Interesting observation Hasan. Another SIMPLE
solution is my elevated GP trick, placing insulated
1/4 WL radials at 10 to 15 ft above ground, just like
a sloper, but horizontal and low on the tower. The
length of the radials can be adjusted for resonance.
It helps to have an antenna analyzer, preferably one
that will show both resistance and reactance, for
tuning / matching. SEVERAL people have told me
they have used this technique successfully with
as few as two radials. Of course more is better.
I insulate the radials with nylon cord loops and
connect the wires directly to the center conductor
of the feedline. Tom N4KG
> I would model your situation wit EZnec and see what is
> really going on.
There's nothing like a good model ! N4KG
________________________________________________________________
GET INTERNET ACCESS FROM JUNO!
Juno offers FREE or PREMIUM Internet access for less!
Join Juno today! For your FREE software, visit:
http://dl.www.juno.com/get/web/.
________________________________________________________________________
This list is sponsored by the new eHam.net Store. When you buy products
like ICE filters, Array Solutions StackMatch, or M-Squared Antennas from
the eHam Store for the same price you pay direct, a portion of the sale
price goes to support this list. Check it out at http://www.eham.net.
-----
FAQ on WWW: http://www.contesting.com/FAQ/towertalk
Submissions: towertalk@contesting.com
Administrative requests: towertalk-REQUEST@contesting.com
Problems: owner-towertalk@contesting.com
|