N300 WiFi USB Adapter - Can't Connect to the WiFi

I have a wna3100 adapter. (USB 2.0)  On bootup (Win 10) it finds and connects to our (3G) Virgin Mobile MiFi (about 50 ft away).  Periodically (about 1x every two hrs) the adapter loses connection to the MiFi and does not restart (also does not find either of our two WiFi devices).  Unplugging and replugging in the adapter allows the adapter to see both WiFi devices and allows reconnection . . . for another 1-2 hrs.   My cellphone (Samsung S6) does not appear to ever lose connection to the MiFi device from the same location.  Any suggestions as to what the problem is and any solutions to the problem?