On Wednesday, 10 November, 1999 10:21 AM, Bill Heinzinger
[SMTP:w9ol@dataflo.net] wrote:
> I've seen ads for a Barker/Williamson folded dipole for 160 thru 10.
> It's only 90 some feet overall.
> Anyone use this design and does it work.
> Does anyone have formulas/instructions for making something like this.
> I'm real estate challenged and even a modest folded dipole performance
would
> beat what I have for 160/80.
One of these is installed where I work for a Y2K back-up (actually back-up
to our back-up--sat phones) to allow regional communications among MAPP
utilities. It does work, that is it has very broadband coverage (low swr)
and handles more than a KW. It work fine using the radios AT on 80 & 160
during our Y2K drill on Sept. 9th.
Two problems encountered:
1) It's mounted on a 100 foot monopole "metal" cellular-type tower. The
"metal" tower detunes the antenna on 40, 80, & 160 making the SWR above 2:1
on 40; above 5:1 on 80; & above 8:1 on 160. A regular dipole would've been
better obviously, but no time (man-power) available to make a change once
this was discovered (even though we have the WX for it still!).
2) This isn't a problem with the antenna per se: But due to the high SWR,
we cannot use the Icom PW-1 amplifier on 40-160 even though it has a built
in AT unit. Icom says the AT-unit can only "memorize" an auto-tune if the
SWR is LESS than 2:1!!! Yes, that is what they said. It only tunes and
memorizes what doesn't really need tuning to start with, otherwise is has
to "retune" on every transmission even after it has been tuned already.
The Auto-tune feature is basically useless on the PW-1 for my
application.
73,
de ed -K0iL
k0il@arrl.net
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