As commonly used (as on this thread), takeoff angle is a property of an
antenna, meaning the angle at which the antenna gain is maximum. What
does that have to do with the angle of the wave being used for
communication? Does changing the takeoff angle of your antenna somehow
magically change the height of the ionosphere?

Let's say the wave angle for communication is ten degrees. I have one
antenna with a takeoff angle of ten degrees and another with a takeoff
angle of 20 degrees. Which is better?

Roy Lewallen, W7EL

Cecil Moore wrote:
Roy Lewallen wrote:

Can someone please explain to me why a lower takeoff angle is better?


Quoting from an old ARRL Antenna Book:

"Rays entering the ionized region at angles above the critical
angle are not bent enough to be returned to Earth, and are lost
in space."

"A significant loss of signal occurs with each hop. ... Assuming
that both waves do reach the same point, the (one-hop) low-angle
wave will contain more energy" (than the two-hop higher angle wave).
--
73, Cecil, W5DXP