Date: Mon, 22 Apr 2019 22:53:26 -0500
From: Greg Best <gregbestconsultant@yahoo.com>
To: towertalk@contesting.com
Subject: [TowerTalk] MODEL FOR TOWER
<I have an 80 ft Rohn windmill tower that is equivalent or stronger than the
same height SSV. The base dimension is 7? 7? and the tower tapers to 24 ? at
the top . I am wondering if anyone has a NEC model for this tower (or a very
similar one)? I have a 20 m 4 <el yagi I am considering installing at abt 60
ft and I am concerned about the tower impact on the pattern. The yagi at 60 ft
would be in a stack with another yagi at 95 ft that is mounted on a mast.
<Greg Best
## what are the tower dimensions at the 60 ft level ? Are you planning on
rotating the 20m yagi at 60 ft ? If so, how do you intend to rotate it ?
IF the tower is say 3 ft on a side at the 60 ft level, depending
on how the yagi is mounted, could possibly create issues. However, being a
4 el yagi, you should have plenty of space between DE and 1st DIR...so it
might be a moot point. Back in the early 80s, I side mounted a
hb 20m yagi, on a 30 ft boom, with equal spaced eles.... onto the side of a
triangular L+R tower, which had a face width of aprx 34 inches. Those
sections were straight, not tapered, and sections were 20 ft long.
Zero issues on 20m. No interaction between tower and yagi, but I had 10 ft of
space to play with, in the middle of the boom. Might be different story if a
say 204BA was used, with its 26 ft boom.
Jim VE7RF
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