Sprint in most areas use 1900Mhz channels. ATT in SOME areas has 1900Mhz channels. The antennas might be able to be used but the outdoor antenna would most likely would need to be aimed at an ATT site (assuming you can see one). Most of the indoor antennas we use are Full band meaning they work from 700Mhz to 2500Mhz. They look like smoke detectors. If you are thinking about installing your own repeater and kicking them out, 1st you must have a waver from ATT to install your own repeater, (there will be a lot of discussion about this but that is the law) 2nd you must buy approved ATT equipment, (right now I think there are only two) 3rd real repeaters cost over $5000.00. Will ATT pay for it? If you have a business case you can talk it over with a rep and they will make a decission based on return on investment. Do not listen to the multiple replies about go buy one on line for $300.00. They are part of the reason ATT has issues on UMTS and you place your company at risk of a $10,000.00 fine from the FCC. Good luck.