As an aside, the "214" dB is probably to do with the way the Netgear displays negative SNR figures.
Instead of -1, the netgear will display 2,147,483,647 dB. Why? It just so happens that in binary, this large number is denoted as 0111 1111 1111 1111 1111 1111 1111 1111 and -1 is denoted as 1111 1111 1111 1111 1111 1111 1111 1111 (etc).
I don't know quite how it comes about, but perhaps the code that saves the value only writes 31 bits, or perhaps the display code reads the long string of 1's back and incorrectly interprets them as the number 2,147,483,647, which is faithfully read and interpreted by RouterStats!
So yeah, it's an amusing, but also quite annoying, bug!
(And there endeth the binary lesson!)