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[TowerTalk] TH7 Advice found & appreciated!!

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Subject: [TowerTalk] TH7 Advice found & appreciated!!
From: (Kurt Andress)
Date: Fri, 06 Aug 1999 09:11:22 -0700

"Gary McDuffie, Sr." wrote:
> Just be careful that you don't go too far.  I don't remember just how
> much overlap was available on mine, but (if I remember right), I didn't
> go further than I did because of the lack of enough overlap.  I can't
> remember right now how much they consider enough, but Roger can supply
> that number for you, as he did when I was doing mine.  It is a number
> derived from the diameter of the tubing involved (something like 3xD or
> some similar formula).  This overlap is needed to maintain structural
> integrity.  Wouldn't want it to break apart at the joint.

You're right about this! I pulled the section apart and found that there
was plenty (> 3 x Dia) left overlapped, so I went for it. But, It should
be checked.
> I'm very interested in the work you did with the balun.  I may want to
> replace my stock one some day.
It took me about 4-5 iterations to get it figured out. It was nice to
have a good BN86 to compare to. 
I did it all with the antenna @ 13' on the AB477, so eventhough the swr
curves were not what the antenna would have at final height, I had
something to provide target values at the low height.
Got it looking fairly close at the low height, then raised it and found
it was still pretty good.
The help I got from the TT gang was key in making me aware of what to
consider in the process.
It appears that many others have also done this, and it seems that they
may have done it with different configurations.
I ended up where I did, for no particular reason, other than it worked!
And wanted to pass it on as a possible option for others considering the
same thing.

73, Kurt, K7NV

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