That is very possible, people will usually see a HUGE decrease of signal strength and speed when a tower, or towers, are shut down for an upgrade. But, it should be up soon and hopefully for you, with LTE!
Loving the updates guys! Hopefully LTE will be solid throughout the Minnesota market by the end of the year! Still waiting for it in Willmar, but I am doubting we will be getting it soon. I just hope it will be by next school year. Anyways, sprints 4G LTE network is sounding pretty fast from what you guys are saying! Hopefully we can get that nationwide soon!