Model :

Hardware Version : Not Clear

Firmware Version :

ISP :

Hi,
I have 2 routers, Archer C7 and WDR4300,
My house is 1 stature but long, Currently I have in my room the Archer C7,
Then I connect it with wire to WDR4300 sits in my roof (concrete roof),
Both routers with the same SSID (Also 2.4Ghz/5Ghz have the same SSID), but I set the channels to "Auto"),
I get good coverage (I think) but I want to get the best coverage from these both routers,
What I can improve? maybe antennas?

Regards.