HI Mike,
> weren't really working properly. One thought that came to mind was the
close proximity of the 1000'
> TV trasmitting tower present at the site with its long conductive guys.
Near field coupling is not set just by the wavelength, it is determined by
the physical size of the antennas. That 1000 ft tower will couple well to
things all around it for thousands of feet, especially long antennas.
Grounding the Beverages to guy line anchors is an ESPECIALLY bad situation!
> pattern, good F/B). The other question I have is what effect will the
irregular mountain terrain have on the
> beverage performance. Seems that this might cause the characteristic Z of
the beverage to vary considerably
> which might in turn make it hard to achieve a good F/B ratio (due to
structural reflections). Anyone have any
> thoughts on this?
There isn't much change in impedance with height, unless you really make a
drastic change over good soil. The change is actually less than the books
and models predict. I doubt that is the problem.
> possible to ever get them to work really well. If this is the case,
perhaps I might be better off to investigate
> alternative receive antennas (probe arrays, EWE's, etc).
Antennas that are small and form their patterns close to the antenna are
more immune to coupling to the tower than large area antennas. An EWE might
be better (it is really just two short phased verticals) IF you have a good
ground under the EWE and if the null of the EWE is in the direction of the
tower.
When I used WXEZ FM in the 70's, I used single dipoles at 350 feet. The
dipoles often outplayed my Beverages for receiving anyway!
73 Tom
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