Ed, stacking these two antennas does not present insurmountable phasing
issues. You could model it and see. It might have unexpected results
because of element spacing, etc, but nothing the model wouldn't show you in
advance of actually going through with it.
If the issue is splitting the power between the two, I could understand
someone saying it was a headache for a number of factors, but an Array
Solutions Stackmaster (commercially available product) would eliminate all
those headaches and make the system quite straightforward to use, i.e. a
switch that allows you to select TOP, BOTTOM, or BOTH and you're done (equal
length coaxes to each antenna).
Many hams stack two dissimilar tribanders these days with excellent results.
Take-off angle is one of the main reasons people do this. Having different
choices available at the flip of a switch will really open your eyes. You
don't have to know exactly which antenna is best for which distant DX
station (and it could be different on two different days), all you have to
know is "is he louder on the top antenna, the bottom antenna, or both of
them together?"
Get a Stackmaster and you will LOVE it.
Mark, N5OT
----- Original Message -----
From: "Edward Sylvester" <navydude1962@yahoo.com>
To: <towertalk@contesting.com>
Sent: Friday, August 18, 2006 11:30 PM
Subject: [TowerTalk] Stacking Dissimilar Antennas
Sometime back, I posted an inquiry regarding having two dissimilar antennas
on the same tower. In this case, I would have a 4 ele Steppir at 70' and a
3 ele Steppir at 35-40'.
Initially, I figured there would be an advantage to this, but after much
feedback from the group, concluded that this would not be worthwhile,
primarily because of phasing issues.
But if I don't combine the antennas and simply have them completely
separate, is there an advantage here in terms of vertical take off angles
because of the different heights of the antennas (i.e. lower antenna better
for short path and higher antenna better for long path and short path to
farther places)?
Or am I just spinning my wheels and reaching a point of redundancy?
Your thoughts are appreciated.
73,
Ed NI6S
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