RK Henry wrote in
:

Of course that was most likely at relatively low altitude in the
practice area, near civilization. Many areas where I fly there's no
cell coverage at all, on the ground or otherwise. A look at the
service provider's coverage map tells the story. Much of the area is
RF wilderness.

Actually, I have found my cell phone to work better in God's country then
over civilization. Less cell towers to hit on to confuse the phone is my
guess.

My experiences is that the higher you go, the less reliability you get.
For me, seems that 6000 AGL is the point where the reliablity decrease
substantially. Other then my own experiences, nothing to back up to the
reasons why.

Allen