Duluth is on the list of cities slated to get 4G in the coming months (see the latest wall post on s4gru) but I'm not aware of any specific network vision upgrades just yet in the Duluth area.
However, I have noticed (via sensorly app) that eHRPD has been enabled on quite a few towers including towers in the Woodland/Hunter's Park neighborhood, downtown, and near the mall. I have also noticed big change in the 3G speeds downtown, I have been pulling 1.5 - 2 Mbps during speed tests; although that could just be due to some non-network vision upgrades that have occurred (see network.sprint.com). As soon as I notice any LTE signals popping up I plan on posting.
