Question Can i connect routers to each other to extend range?

Feb 20, 2019
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So i have one ethernet connection coming from the ground, it is connected to what i believe is a router (black box).

It gives OK connection if u are downstairs (both wifi and ethernet)

But the connection is too weak upstairs.

So is there a way i could buy a new router, connect it to a cable to the router downstairs, and to put the new one upstairs to extend the connection to there?

The router downstairs has 6 lan ports, and 1 Wlan port.