[TowerTalk] MODEL FOR TOWER

[Jim Thomson]

Date: Mon, 22 Apr 2019 22:53:26 -0500
From: Greg Best <gregbestconsultant at yahoo.com>
To: towertalk at 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