|"400 feet away"|
You can stop right there. 328ft is the max you can have without a repeater.
"I was told by linksys I had to use a different router to be able to cascade them "
You got a tech who didn't know what he was talking about. You can cascade two of the same manufacturers routers no problem. If both are doing 192.168.1.x for ip you change one to 192.168.0.x
That's all there is to it.
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