[TowerTalk] Stack questions

[Jay Terleski]

Pete,
I wonder why you see such drastic changes in your SWR. I see no change
by rotating my 3 high stacks.   Perhaps the spacing of your C3Es are too
close. But I think I remember you did space them properly.  What is the
spacing between them, and how long is the boom on just the 20m
elements.  

Could it be that the proximity of guy wires is changing the SWR, or
perhaps just the rotation of the antenna around the tower?

Try (as I am sure you already have) turning the lower antenna while it
is only selected and see if the SWR varies as it is rotated around the
tower.

Jay, WX0B

Pete Smith wrote:
> 
> I'm still in my first month with my stacked C3Es, and while they seem to
> work FB I have some questions for more experienced triband stack users.
> 
> 1.  Is it to be expected that the SWR will be different, with the antennas
> fed in phase, when they are pointed in different directions compared to
> when they are aimed the same.  The effect is fairly significant -- for
> example on 20m SWR is 1.4:1 when pointed in the same direction, but drops
> to 1.1:1 when they are 180 from each other.  I think I can undersatand why
> this should be conceptually, but...
> 
> 2.  It seemed to be worthwhile to point the 2 antennas differently during
> SS -- for example, I would put the top one west and the bottom one south or
> north.  Is this also potentially useful during CQWW (pointing the lower one
> toward SA, for example), or am I better off keeping everything on Europe
> and picking up SA off the rear quarter as needed?
> 
> By the way, on 95 percent of occasions where I have checked so far, the
> stack has been superior to either antenna alone, and I've only had one case
> where the lower one was noticeably better.  I suspect that at 69 feet, the
> lower antenna still isn't low enough to optimize for the middle of European
> openings on 10m.
> 
> 73, Pete Smith N4ZR
> 
> Contesting is ... Extreme Radio
> 
> The World Contest Station Database
> is back up and running at
> http://www.qsl.net/n4zr
> 
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-- 
Jay Terleski
WX0B - Array Solutions
www.arraysolutions.com

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