Hello. Any know.

How far out do cell phones work on the atlantic around Key Biscayne to
Key Largo. Elliot Key is about 8 miles out from Black point marina,
does a cell phone work to and from the mainland?

Also, new to boating, and my boat has ship to shore radio, I think it
was getting a signal when I tested the boat, would that same radio
produce any signal or even turn on with the key out and the boat 15
miles inland? Getting nothing right now.

Thanks!