[TowerTalk] Triband Evaluation Query

[Stan Griffiths]

>I am thinking of putting 3 monoband yagis on one boom, how can I find out
>if they are going to fight with each other before i do it. I have tried a
>couple of shareware programs, but it only allows for single band stuff. 
>
>Here is what I want to do:
>5 elements on 10
>5 elements on 15
>4 elements on 20
>all on a 26 foot boom
>For the final director in each antenna It was going to be a trapped element
>that would work as a director for all 3 bands ( old director from a Telrex
>Yagi) 
>
>According to my reading and books I have as single monobanders all will
>work ok, Now I want to go and screw that up and try to put them all together. 
>Any Ideas, comments, or tutorials???
>
>TNX
>Mike...NO6X

Hi Mike,

I cam pass some info to you about interlacing monobanders on one boom.  Back
in the '70s, Wilson marketed several interlaced two band Yagis for 15/20 and
10/15.  I don't ever remember seeing anything about a  Wilson interlaced for
3 bands.  Wilson's advertising literature sounded GREAT.  Everybody I knew
who bought one (three different guys) were unhappy with the performance with
the "inner" antenna and in each case, they finally separated them to
different booms.  They just did not seem to have a decent pattern with
nearly zero front to back.  The "outer" antennas seemed to work pretty much
like a monobander of the same dimensions.

In an entirely different case, I once visited the station of W3GRF and he
had three bands of Yagi elements on one boom but he did not interlace them.
He had two elements on 20, 3 elements on 15 and 4 elements on 10, as I
recall it, but they were "in-line" and not interlaced.  I never got to talk
with him about what he thought of its performance.

I have no experience at all with modeling programs so I have nothing to
offer you on that subject.

I do recall hearing about a ZS who once had two monobanders (on 15 and 20, I
think).  He made each antenna perform well by itself and then he laid the 15
meter boom and elements right on top of the 20 meter Yagi.  They both
suffered poor performance.  He then moved the 15 meter boom and elements
back and forth along the 20 meter boom until he found a place where BOTH
antennas seemed to work fairly well.  He transferred the 15 meter elements
to the same locations on the 20 meter boom and used the antenna that way.
Sorry I don't have any more details on that one.

Good luck with this project.  I don't think you will find it easy . . .

Stan  w7ni@teleport.com


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