Nighthawk MR1100 Hotspot

Hello,

I have a Nighthawk LTE Mobile Hotspot, MR1100, through AT&T.  When I performa speedtest, it appears as though I am connected to a cell tower over 30 miles from my home.  I know there are towers within 5 miles from my home that ATT uses.  How do I connect the Nighthawk Hotspot to the cell tower closest to my home? TIA.