Hi, Everybody,

How does one determine the correct antenna takeoff angle to communicate over
a certain distance?

I can't find any references anywhere that discuss this, taking into account
all of the variables: height of ionosphere, frequency, etc.

Here's a practical example of when it would be important to know this. Say
you are going to put up a dipole antenna for 20 meters specifically to
communicate to a friend 2000 miles away during the day. The takeoff angle of
the major lobe varies widely as the antenna is raised from ground level to 1
wavelength above ground, so presumably there is a 'best' height for the
antenna to put the major lobe right where it needs to be to skip to your
friend's QTH.

The trouble is, we do not seem to have a good way to determine this 'best'
height ahead of time. One would, I guess, have to vary the height of the
antenna while the other station monitored your signal strength, and one
would have to do this over several days, weeks, or months to get good,
averaged data. But... isn't there a better way to do this?

Regards,

Al W6LX