[TowerTalk] FW: Spacing of Antennas

[Matt]

>From past modeling analysis, 17m monoband was not predicted to play well
with a 40m moxon stacked below it at about the same spacing that you are
looking at.  When modeling the antenna combo, there was enough interaction
to predict a fairly significant drop in input impedance for the 17m antenna
and the F/B was predicted to be significantly degraded.  Might have been
possible to iterate a corrective solution by manipulating the position and
length of the 17m elements but I decided to put the 17m antenna on a
different tower instead.

Matt
KM5VI

-----Original Message-----
From: TowerTalk [mailto:towertalk-bounces at contesting.com] On Behalf Of Byron
Tatum
Sent: Wednesday, October 01, 2014 3:23 AM
To: towertalk at contesting.com
Subject: [TowerTalk] Spacing of Antennas

Hello-
  I am planning an installation and wanted to ask if:
     1. Is 10' of vertical separation (on my 2" mast) enough to avoid
interaction issues between an (Cusgcraft A3-WS with 30 meter kit, bottom
antenna on mast) and a (Cushcraft "World Ranger" 40 meter rotary dipole,
mounted higher on mast)?
     2. I would prefer to have the 40 meter rotary dipole parallel to the
elements on the A3-WS, so they are both "aimed" in same direction; however
years back I mounted the same 40 meter rotary dipole only 4' above a A3
tribander and had interaction issues - ended up turning the 40 meter rotary
dipole to where it was parallel with A3 boom which helped a lot.
    Thanks for any insight,
       Byron WA5THJ  
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