I have a similar problem, neither of my two Omega+ can find my home wifi.
I have two access points, both capable of using the 2.4 GHz band and not exclusively 802.11n. The SSID of the main AP is eight characters long, alphanumeric and '-'. I can connect to the O+ over wifi or serial, but when scanning for available networks 98 % of the time they find none, some odd times it discovers my neighbour's wifi.
Never before have I encountered any problem connecting to wifi at home with any other device.
I have tried to enter the information manually, but it still can't connect.
I am currently at work, where there are lots of networks available, including open ones, and still the device does not find any network at all.
Are both my cards broken?