I'm dealing with some fringe areas on both AT&T and T-Mobile, and, I was wondering if there is a way (e.g. an IOS app, but, I've looked and haven't seen it), to see what the actual band availability is at a location, and, which option the phone is using. The carriers continue to recarve their allocations, and, I would like to know which bands they are using in certain areas before I buy my next (unlocked) GSM/LTE phone.