I've had many blackberries and am far from a newbie, so I've done all the obligatory checks. That's what is so frustrating. I've done the searches and tried all the standard tips, tweaked settings, etc.
Also, I specifically checked the signal strength, and in all cases it's been full. (I never have signal problems where I am and can frequently talk in the elevator too).
Too weird. Hmmm....
But thanks for the suggestions.