This subject is very interesting to me. I have been doing a
lot of thinking on this subject in the last few weeks. I have
more or less seperated the bands to seperate towers at my present
QTH. As I embark on a new station design I had sort of forgot the
lesson the Bill pointed out. There is nothing like physical
isolation for minimizing interaction.
73 Pual
At 01:36 PM 12/22/98 -0500, Bill Fisher - W4AN wrote:
>I was fortunate to have operated at two very good stations (N4RJ and
>K4VX). One thing that was common at both stations was the lack of nearby
>antennas. At N4RJ, Val had one band per tower. I now believe that this
>was a large part of my success at this station. He didn't have any
>"unkowns" screwing up the pattern of his antennas.
>
>With the few towers I have modelled so far, it is interesting to see how a
>nearby structure can totally screw up a great pattern from an optimized
>antenna. I now have to wonder about these guys who stick up a ton of
>antennas on one mast or tower.
>
>We spend a lot of time modelling antennas in free space to eek out the
>very last 1/10th of a DB. Then we take that antenna and stick it up in
>the middle of an aluminum jungle. Not sure that makes much sense.
>
>One thing I have learned is that my 4-square which surrounds a 115' Rohn
>45 tower is definatley affected by the tower in the middle. The F/B goes
>from a 25DB in the perfect model to 18DB or 19DB with the tower in the
>center of the square. In my case, it's the only place I can put the
>verticals. But it explains a few observations.
>
>Has anyone else done any complex station modelling to see the affects of
>nearby antennas?
>
>73
>
>Bill
>
>
>--
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