Those large devices that have that big antenna you put near a window do work, but they're also kind of expensive (with the added advantage they usually work with all carriers). We had one at my last employer because in the basement most of us didn't get signal. However, now if you could I'd get one of the carrier-official boxes
The internal antenna crap mostly (if at all) do not work.
food for thought - By Mhunter - 












