[RayChez1]

It has nothing to do with the coach. I have a Scenic Cruiser and we use our cell phones all over the country with no problems. But it all depends as to who you have as a provider. We used to have AT&T and they have a lot of dead spots in the country. We switched to Sprint and we have not had any problems, unless you are deep in a canyon where the signal can't get out, but other then that it has been great.
But since you did mention a add on booster, I did get to talk to another RVer up in San Diego and he was selling an attachment for cell phones. They probably do work if you are in a remote area surrounded by mountains, but for us Sprint has worked just fine. But the Scenic Cruiser for sure is not at fault. LOL