I been having the issue also where my mobile is getting the message " avoided poor internet connection", also it states there is 90 % interference on occasions, what channel on the SMC router/modem
So you're seeing the same thing on both your tablet and your phone? I'm assuming wired is working well, so have you tried changing the channel on your SMC using these steps?
Mine is mostly my cell phone, I have gone through the channels and it looks like 4 is holding up right now I will check later after work to see if there is a change
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