Most modem combo's Wi-Fi sucks.
It would be better to this...
#1 Get your own RJ-45 WAN port NAT router.
#2 Make sure that the WAN Port of the RJ-45 WAN port router works.
#3 Put the RJ-45 WAN port router in the most central place of the house/business (if it is not there already). Note: Where central also means, not top floor/bottom floor - not just center the other way.
#4 Put the modem combo into bridge mode. See REF = http://www.dslreports.com/faq/13600
#5 Profit. 🙂
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