[TowerTalk] stacking different antennas

[john at kk9a.com]

I think the phasing difference in using different antennas comes from the 
driven element not being in the same vertical location.  You can adjust for 
it by adding more coax to one antenna, however calculating this may be 
challenging.  It's probably not that critical.


To: TOWERTALK at contesting.com
Subject: [TowerTalk] stacking different antennas
From: tk4xs
Date: Fri, 9 Mar 2007 21:20:39 EST
List-post: <mailto:towertalk at contesting.com>

As I mentioned in an earlier post, my proposed antenna system in KH6 is in 
a
state of flux.  I know I will be using three SteppIRs....two of the 4 el 
(20
through 6) and one MonstIR for 4 el (40 through 6).  They will be more  than
likely be around 27, 54 and the MonstIR at around 90.

My permit is still in the building department, and may come through at 90 
or
150 ft...still unknown at this time.  If the 150 feet comes through I  may
mount a 40 meter monobander at that height and phase it with the  MonstIR.
Modeling it with HFTA makes it look truly like a "Monster".

I have no desire to mount a second MonstIR at 150 because:

1. price
2. at my QTH 150 feet HFTA says it is way too high to produce a usable
signal on 20 through 10
3. wind load

So, what I want to do is to mount something like a M2 40 meter monobander 
at
140-150 and phase it with the MonstIR at 60-90 feet.  Has anyone ever
stacked dissimilar antennas, and if so, what kind of results did you get? 
I
know
there may be a phasing difference, but I will be running identical  lengths 
of
coax to them, so I'm not sure where the phasing difference that guys 
mention
in this stacking comes from.

The MonstiR should behave like a monobander on 40 and my guess is should
stack like a monobander.  Am I missing something.   Any thoughts  on this?

Bill K4XS/KH7XS
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