Quote Originally Posted by Rooster View Post
There is really little need for building (or buying) antennae with "gain"
Aircraft fly in essentially a hemisphere over your head...
Actually they don't fly in anything like a hemisphere, I can detect aircraft out to 300+nm in all directions other than straight up! I suspect that if they flew at that height the ISS would be considered a collision risk��
Antenna don't require much gain straight up as the distance to an aircraft overhead is much less than one on the horizon, that is where you need the gain.