[TowerTalk] vertical dipole - tower interaction question

Robert G. Strickland rcrgs at verizon.net
Mon Oct 22 21:23:39 EDT 2007


Hello to all...

Thanks all on discussion of SkyHawk and KT36XA. Decided to go with the SkyHawk.

New Question...
What, if any, is the interaction/degradation of a vertical dipole about 2-4 
feet from a Rohn 25 tower? The tower is 60ft tall, and the dipole with be 
shortened/loaded. The bottom of the dipole will be about 20ft up the tower, 
and the top of the dipole more-or-less at the top of the tower [do to 
architectural constraints]. I plan to feed the dipole with 450ohm window 
line. The feed will come straight away from the  center of the dipole about 
4ft, gentle curve down, then straight down to a balun-coax transition to 
the tuner. The down section of the window line will be twisted 360deg about 
every three feet to "attempt" decoupling from the antenna and the adjacent 
tower [about 1ft from the feed line]. I have modeled this setup on EZNEC 
which shows no interaction. The dipole vert/horz patterns look like one 
would expect. What's the conventional wisdom on this setup? If not 
workable, what might I be doing wrong in EZNEC that's missing the problem? 
Thanks much in advance.

...robert

Robert G. Strickland PhD ABPH - KE2WY
rcrgs at verizon.net.usa
Syracuse, New York  USA



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