True, but I think that's also, to a certain extent, an artifact of the simple
phasing, switch network (BIP, BOP, Top, Bottom): which sort of gives you 4
different patterns in the elevation axis. If you have a variable phase shift,
you can steer the beam quite a bit.
It is unclear how much this would buy you (for significant increased
complexity) - the beams are broad. Probably more useful is the ability to put
a null on a take off angle that is giving you interference. (and on Tx, to
avoid sending Tx power to an undesired elevation angle).
On receive, doing this is pretty easy with modern SDRs, but on Tx, it's more
challenging - you can't just generate multiple signals that are phased
differently and run them into a PA, because the antennas interact, and power
from amplifier N couples into the output of Amplifier N-1 and N-2. For large
HF arrays (think Over The Horizon Radar) they do this, and there's a whole lot
of modeling and testing that goes into forming the beams correctly.
On Mon, 7 Apr 2025 09:05:55 -0600, Tom Hellem <tom.hellem@gmail.com> wrote:
Ron-
The reason stacked tribanders don't work as well as monobanders is
that you can only optimize the stacking distance for one band.
I have used a stack of tribanders, though, and I can attest they
are better by far than a single yagi.
Tom
K0SN
On Sun, Apr 6, 2025 at 8:02 PM Ron WV4P wrote:
> I am very surprised to learn that multi-band antennas do not work well in
> stacks.
>
> Ron, WV4P
>
> On Sun, Apr 6, 2025 at 8:48 PM Mike Fatchett W0MU wrote:
>
> > He could have used 20m monobanders and saved a ton of
> > money......Obviously money was not an issue. 4 80 ft towers as the
> > supports.....etc.......And then when it broke you were SOL.
> >
> > W0MU
> >
> > On 4/6/2025 7:34 PM, Richard (Rick) Karlquist wrote:
> > > A stack in 2 dimensions like that only works well on one band.
> > > It won't be anything great whether SteppIR's or any other tribanders
> > > are used. W6BH tried a stack of KT34's (only vertical stacking)
> > > and it didn't work very well, which should have been obvious without
> > > building it. As was said, more cents than sense.
> > >
> > > 73
> > > Rick N6RK
> > >
> > > On 4/5/2025 9:27 PM, john@kk9a.com wrote:
> > >> K9LTN became a silent key in 2009. It would be interesting to know
> > >> if that
> > >> system ever worked and what happened to it.
> > >>
> > >> John KK9A
> > >>
> > >>
> > >> David Gilbert AB7E wrote:
> > >>
> > >> I wonder what happened to it. K9LTN is an expired callsign.
> > >>
> > >> Dave AB7E
> > >>
> > >>
> > >>
> > >> On 4/5/2025 7:23 PM, john at kk9a.com wrote:
> > >>> Imagine this maintenance headache:
> > >>> https://www.kkn.net/dayton2006/K9LTN.pdf
> > >>>
> > >>> John KK9A
> > >>
> > >>
> > >> _______________________________________________
> > >>
> > >>
> > >>
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> > >>
> > >
> > >
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> > >
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