Those are great points Dave.
Since I do not have an Engineering research background nor did I train
as a theoretical mathematician or theoretical physicist, I have had to
learn what I have learned the old-fashioned way, by observation. There
are great advantages in that method since it is real-time and you can
choose what you want to study. In my case, I have many antennas at my
disposal at different heights and different wave angles - horizontal,
vertical and hybrid (both vertical and horizontal), providing an almost
limitless variety of points of comparison that can be switched in and
out within a fraction of a second. The drawback is obvious though - the
data is anecdotal because it not be accurately measured and quantified
on a repeatable basis. But for my application - making qso's - it is
fabulous. :-)
However, my 4-stack of yagis on 10, 15 and 3-stack on 20, with the
ability to switch in any combination of antennas, provides an advanced
seminar of propagation and wave angle variation in the course of a
48-hour contest. And it is a lot of fun to continually switch the
combinations and observe what is happening as it happens and conditions
continually change. And just when you think that you have learned
ALMOST all there is to know, the ionosphere will throw some new
combination of phenomena at you that you have not seen before and that
makes the bands behave in a new and different way.
The maps of FT8 activity and the RBN network SNR reports also provide
useful and interesting data that can piggy back the real-time signals
propagation observations to make the equivalent of a 3D data point out
of 2D data.
That is most interesting to me, but well above my ability to integrate
all of that in my station and between my ears in real-time. LOL!
But it is intriguing. Maybe if/when I retire and I have a lot more time
and resources to play with, I can attempt something as ambitious as what
you describe. :-)
73
Bob, KQ2M
On 2026-01-15 13:02, David Gilbert wrote:
What is say is absolutely true, but in today's world it would be
possible to actually quantify some of those things.
For real time propagation it is hard to beat PSK Reporter's map of FT8
activity, assuming you have a receiver posting reports to it ... or
somebody living near you that is doing so.
As for as monitoring real time arrival angles of incoming signals, I
keep telling myself I'm going to write a browser-based application that
takes the 2-channel audio feed from a rig with two phase locked
receivers (a K3 with new synths in my case, but there are other rigs
that can do it) connected to two antennas and computes/displays the
phase difference. It's the kind of thing that is often used for
diversity reception in the horizontal plane, but it could be done with
over/under dipoles as well. It works in a browser because the relative
phase of two RF signals is preserved in the conversion to audio.
The app could also incorporate phase shifting of one signal and then
adding or subtracting it from the other to achieve directional
beaming. The volumes could be equalized just using the knobs on the
rig.
I haven't done it yet, though. And it might be simpler just to buy an
SDRduo and run it using SDRuno in diversity mode. No reason that it
couldn't be done with over/under dipoles.
In all cases, a small oscillator (crystal controlled or something like
the popular Silicon Labs programmable ICs) positioned between the two
antennas could provide a reference to compensate for the phase
difference in the two feedlines.
Dave AB7E
On 1/15/2026 11:25 AM, kq2m@kq2m.com wrote:
It's sort of like ionospheric propagation - you can use VOACAP and
it's ilk, which make some simplifying assumptions (Chapman layers,
etc.) or you can just use PHARLAP (which is a full on 3D raytracing).
Or you can operate a lot and learn how propagation actually works in
real-time by observing the constant changes in path, wave-angle,
signal strength, etc. and have fun working people too!
And then, when you become a propagation master, you can start to
predict what will happen next just by listening to subtle changes in
the band noise. That's way beyond VOACAP or any propagation program
that exists.
73
Bob, KQ2M
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