Topband: Are stacked verticals feasible?

[Charlie Cunningham]

Hi, Mike

When you say that you use "stacked" vertical beams - aren't they "stacked"
horizontally?

It seems to me that the vertical collinear elements,along the lines of what
Carl is describing,  are generally vertical collinear 1/2 waves in phase -
usually with a 1/4 wave phasing line between adjacent vertical elements.
Sometimes, the lower element in the array is a 1/4 wave monopole that is
part of a ground-plane. 

Regards,
Charlie, K4OTV

-----Original Message-----
From: Topband [mailto:topband-bounces at contesting.com] On Behalf Of Mike
Armstrong
Sent: Friday, September 06, 2013 9:03 AM
To: Tom W8JI
Cc: <topband at contesting.com>
Subject: Re: Topband: Are stacked verticals feasible?

Tom and all,
If I am reading the question correctly, aren't we talking about something
that is done at VHF/UHF with great regularity?  Stacked vertical elements,
stacked vertically polarized beams and all manner of stacked vertical
"anything" are done there all of the time to avoid cross polarization loss
when the other stations (especially mobile) are the main users.  

So understanding that it is done at those frequencies, the answer to the
original question of "can it be done," so to speak, is a resounding YES.  I
just don't have any idea how you could extrapolate that to MF (160
meters)...... It would be a monstrously tall structure..... he he he.
Actually, I have a set of stacked vertical beams that I use for a
point-to-point link with a marginal repeater from my cabin up in the high
country on the Mogollon Rim in AZ...... It is an incredibly effective
antenna that was much less so with a single vertical beam..... Hopefully I
didn't just waste everyone's time by misinterpreting the question..... :) :)

Mike AB7ZU

Kuhi no ka lima, hele no ka maka

On Sep 6, 2013, at 2:46, "Tom W8JI" <w8ji at w8ji.com> wrote:

>> Isn't this a "Vertical dipole"? Two quarter wave radiating elements? And
tower behind it will be some kind of reflector/director depending on height.
The radials seem unimportant if thought of this way.
> 
> Antennas radiate because of the current flow.
> 
> So you would have two current maximums, one maximum near the earth for the
lower element, and another maximum  higher up about 1/4 wave away from
earth.
> 
> The end result would be earth conductivity dependent, but somewhere
between a little better or a little worse than a 1/2 wave vertical. The
spacing of current maximums would be a little wider than a vertical dipole
or half wave vertical, but still too close for any real significant gain.
Because a current maximum would be at earth level, ground losses might eat
up any very small gain.
> 
> Maximum stacking gain with 1/4 wave between current maximums is about 0.5
dB. This is reduced because the bottom element is against earth, and could
even go negative. Most of any gain, if it had gain, would come from the top
element and the earth reflection. 
> _________________
> Topband Reflector
_________________
Topband Reflector