wrote:
. . .
Now Roy I have a problem with what you are saying here
I spend hours modelling an array to lower the TOA or angle of max radiation
which directly controls the main lobe dimension both in width and height.

And, as I've said quite a few times in one way or another, it's largely
a waste of time.

I model an antenna array such that it emulates in a way a "stacked"
array where as low as a 9/10 degree TOA. The 3 db gain window is broader in
width and narrower
in height than say the normal array. It is this "TOA" that determines what
window we have and
where it hits the ionesphere which thus determines its point of arrival on
the earths surface

That's absolutely incorrect. All antennas radiate at all angles. The
ionosphere doesn't know or care at what angle your antenna is radiating
the most -- propagation will occur at the angle favored by the
ionosphere at the time. Your antenna's pattern doesn't dictate the
geometry of the path.

Not propagation which is the "environment" of all antenners in the vicinity
and the same
for all antennas at a particular time.
The ARRL clearly shows that it is the TOA that determines the range as it
were of one antenna
comparered to the others with different TOA.. For the life of me I cannot
concurr with the statement
as stated.

By speaking of "environment" I was not including propagation, and in
conforming to traditional usage, I also don't include propagation when
speaking of antenna patterns. An antenna pattern is a polar plot of the
field intensity of the antenna at a distant point, but with the
assumption that the propagation to all points is lossless. The actual
signal received at a distant point requires the inclusion of propagation
effects. The pattern is one element in the equation, but only one.

. . .


Is this the error of my ways where any change I make to an antennas pattern
is rendered of no use because I must first find a way to manipulate
propagation
where all the action is really at?
. . .

Close. Sometimes two or more propagation modes are possible, such as
single and double hop. From here to say, New York, I might have single
hop at 3 degrees and double hop at 12. (Please forgive me if those
particular propagation angles can't really occur at the same time, but
they're in the ballpark.) It doesn't matter one iota what the angle of
maximum radiation from my antenna is. All that matters is the gain or
field strength at elevation angles of 3 and 12 degrees. All the rest of
the radiation will go some place besides New York. As a general rule, I
can get a stronger signal to New York with X dBi at 3 degrees than the
same gain at 12, because the single hop path loss is usually less. So it
might pay me to maximize my gain at that angle at the expense of 12
degrees. On the other hand, the other station's antenna pattern is just
as important -- if it has a lot more gain at 12 degrees than 3, he might
not hear me if I put out most of my energy at 3 rather than 12. But in
any case, it doesn't matter how much I'm radiating at 1, 5, 7, or 15
degrees, or what my antenna's maximum angle is. All that counts is how
much I'm radiating at 3 or 12 degrees. Other than manipulating your
antenna to radiate more or less at those two angles, you don't get to
"manipulate propagation" to support other angles at a given time,
frequency, and path. You're stuck with those until the ionosphere
changes. Knowledgeable DXers (which I'm not) spend a lot of time working
out what the angles will be for propagation to various target locations,
and how to design, build, and switch antennas to maximize the amount of
radiation at those angles.


I also want to make it clear that I appreciate your post which I see as an
attempt to clarify matters
that are presently being discussed ie.It is propagation and not the antenna
that determines the
TOA. Or "antenna pattern is determined by propagation" so that we don't
get hung up
on the term TOA

No, antenna pattern isn't determined by propagation. The signal strength
at the other end of the path is determined by the gains of both the
transmit and receive antennas at the elevation angle of propagation, and
the loss along the path. Period. Notice that "takeoff angle" and
"pattern" didn't appear in that sentence. And you don't get to choose
the angle of propagation (unless more than one are supported at a given
time, which is only sometimes true, and then you can only choose between
the supported angles).

I suggest downloading the excellent, free, and easy to use propagation
software by Shel Shallon, W6EL, http://www.qsl.net/w6elprop/. In a few
minutes, you'll be able to see what angles are supported at a given time
and frequency for a given path.

Roy Lewallen, W7EL