Ref. my post about Time Capsule and my 770 not being able to see either the Apple network or others in my immediate neighborhood..

I just checked the 770 connections when turning off the Time Capsule, and bingo, up popped all of my local networks!

I don't know if this is a purely Apple matter or perhaps other 'n/g/b' compatible networks have the same affect on the 770.

Could this be your problem too?