Got a bad cell phone signal? Without a stable connection to the outside world, you might start to worry about what you'll do in an emergency (or which of your friends' Instagram stories you'll miss ...

You know that special kind of holiday-travel panic? Your phone's signal bars just... disappear. One minute you're following the GPS to your in-laws', the next your map is frozen, the festive playlist ...

Spotty reception isn't just an inconvenience when you're on the road, it can leave you cut off from maps, music and emergency help (unless you've got satellite help). If your GPS locks up or your ...