OldPilot wrote:Usage of cell phones in airplanes is illegal in the US. .
That's an often repeated bit of misinformation, but the only actual FCC prohibition that I can find applies only to the original 800 MHZ cell phone frequencies. Even if it were true, a hot spot is arguably not a cell phone.
What is true is that cell towers use antennas that put most of their signal lobe at or below the horizon. Providing coverage at altitude is not a priority to them.
To the originator of this thread: I tried the hot spot idea, and simply didn't find reliable coverage. (YMMV) I finally bought an ADS-B receiver and have much better results. I do wish that ADS-B worked on the ground though! I have to launch before I can discover if any local weather has popped up.