Is it OK to have 2 N routers within range of each other?

I want to "cover more area". But there will be an overlap.

Will two routers of the same type interfere with eachother?
What about different brand?

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from what i've read it is ok,

use the same SSID and switch the second to a different channel
minimum 3 channels away from the main unit.

Disable DHCP on the second unit.

You know something, I don't see an option to change the channel. Is that a G thing only? Are you refering to those 2 / 5 GHz models? Set one to 2 and the other to 5?

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