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[TowerTalk] tribander stacking

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Subject: [TowerTalk] tribander stacking
From: (Jim White, K4OJ)
Date: Sat Jun 7 22:06:56 2003
There is a good diagram of clearance you get from their sidemount at the 
WX0B Array Solution Site...while your IIX size is different this will 
show the downfall of having the driven element in the middle of the beam...

You might try to re-optimize your antenna with YO with a greater 
distance between director and driven element if it were a monobander but 
with a tribander about all you could do is to counter weight one end so 
that the balance point shifts far away from the middle of the boom.

Once saw this done with a quad (Natan you still on this reflector?) - a 
pretty long piece of 2" water pipe was layed in the middle of a 3 inch 
boom to create the shift in balance point needed for the element to miss 
the tower... when I design 4 element antennas I use heavier wall tubing 
on the part of the boom which is closer to the director end of the boom 
than at the reflector end to help offset the way the driven and 
reflector are clustered at the back end... sometimes this is not enough 
and then I purchase 2" electrical PVC (grey) and slide it over the boom 
to find the sweet spot... initially you can simply suspend it below the 
boom with duct tape to see if a pieces length can be altered... I try 
and make that piece align with a boom truss point and then pass the 
eyebolt the truss uses through the PVC which is all it needs - it ain't 
goin' nowhere!

Bottom line is you may wish to shop a different triband beam than the 
atypical A3S/CL33


Jim, K4OJ

Gregg Seidl wrote:
> I would like to know if one can still get about 300 degrees of rotation
> using one of iix'sswinging gate style side mounts IF you use a 3 element
> yagi.I was trying to picture that but I think my view may be wrong.Also I
> see that iix's swinging gate mounts on only one leg,does that really work.I
> know they are not very stellar performers but I might try to stack 2
> A-3's.They are cheap and light and they are reasonable tough.Any ideas
> comments???  Gregg  K9KL
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