[antennaware] Station Modelling

Paul Hellenberg W9JA w9ja@contesting.com
Tue, 22 Dec 1998 13:33:05 -0600

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?  
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Paul J Hellenberg W9JA ex KS9K Tru Line Lithographing Inc.
PO BOX  565      7900 Durand Av., Sturtevant WI 53177-0565
414 554 7300 -125    Fax 414 554 8217    Home 414 554 9170

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