Apple fesses up to wi-fi iPad issues, offers fix
If you've got a dual-band wi-fi router, read on
Some iPad owners have been groaning about a nasty wi-fi problem that's plagued their shiny new device. After the tablet wakes from sleep or restarts, some iPads won't automatically rejoin to a known network on dual-band routers.
Apple has acknowledged that the problem exists, writing on its support website, "Under certain conditions, iPad may not automatically rejoin a known Wi-Fi network after restart or waking from sleep. This can occur with some third-party Wi-Fi routers that are dual-band capable."
The manufacturer thinks the problem occurs with some third-party dual-band routers that have the same network name for both 802.11b/g and 802.11n bands, or different security settings for each band, and the iPad gets in all of a tizzy and can't connect.
Apple suggests renaming your networks to have different names, and ensuring they both have the same security type. Also, make sure your wi-fi router firmware is up to date.
Multiple users on the Apple support forums have reported that raising the brightness level fixed their wi-fi woes. Apple isn't including that as a suggestion on their support documents, but if you're at your wits end it might be worth trying.
Engadget