"Reg Edwards" wrote in message
...

"Reg Edwards" wrote
The elevation angle of a radio wave is not related to antenna
construction.

It is calculated by trigonometry and is geometrically related to the
distance between two points on the Earth's surface, the height of the
ionospheric reflecting layers involved, and the number of hops.

If a radio wave leaves the Earth at one end of the path and returns to
Earth
at the other end, then the elevation angles of the path taken are the
same
at both ends. And the same in the other direction. (To forestall
nitpickers let it be said things can vary around averages.)



Reg.
You asre concentrating on things that you can do nothing about
i.e.the ionisphere and trivialising the things that you CAN do something
about
which is TOA, the subject of this thread.

If the transmitting station TOA is low enough to make the QSO in one hop
and the receiving station antenna has a higher take off angle that requires
exactly two hops to reply then the paths are NOT the same.
I would also doubt that the paths taken when being bent by the reflecting
layers
would be the same as the density is subject to change
.. The real discussion regarding TOA is to achieve a QSO
with one hop instead of two so as to cut down on travel losses and that is
where
the importance of TOA and associated angles that follow the +/- 3 db takes
place.
Regardless of the physical position of the antenna the elevation angle of
the radio wave
IS related to antenna construction.
Just a different view point Reg, the antenna I CAN do something about.
Natures actions
I can do NOTHING about except to have the correct equipment when good
conditions occur
and that is where TOA gains it importance.
In my designs I try to have the lowest contour of the bottom lobe even tho
it may mean
a loss of a db in gain at the actual TOA.and I do not concern myself with
the technical data
that your posting revolves about, which tho it may be interesting to some,
as I cannot change it
Nothing personal nor am I nitpicking
Cheers
Art





The optimum angle at which to point a radio antenna, either for transmit
or
receive, is obviously the same as the elevation angle of the radio path.

BUT NO AMOUNT OF WAVING THE ANTENNA ABOUT WILL AFFECT THE ELEVATION ANGLE
OF
THE RADIO PATH.

For given points on the Earth's surface, height of reflecting layer, and
number of hops, the angle of elevation of the radio path is fixed.

The angle at which the radiation from an antenna is a maximum is an
entirely
different matter.

Calculation of a path elevation angle on a curved Earth not very
difficult
but is a little too complicated to be written here.

Up to 1500 groundpath miles the Earth can be considered to be flat. Trig
calculation is then schoolkids stuff.

Full formulae can be found in maths books under "Spherical Trigonometry"
or
in practical radio engineering books.

Calculations can be interesting but are invariably roughly approximate
because layer height involves guesswork. And by the time you've finished
a
calculation the height has shifted. Or the number of hops has changed
from
2
to 3. The only things which remain static are your own latitude and
longitude.

To calculate propagation statistics of one and two hop radio paths,
including elevation angles, download simple program TWOHOPS in a few
seconds
from website below and run immediately.
----
.................................................. .........
Regards from Reg, G4FGQ
For Free Radio Design Software go to
http://www.btinternet.com/~g4fgq.regp
.................................................. .........

=========================================

Why should my answer to the question be altogether different to everybody
else's? Especially as I'm right.
---
Reg.