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