Nice troubleshooting. nice to see someone actually does something before asking questions on here.
- on your router. make sure you do have the channel set to a static channel such as 1, 6, or 11.
- on the router. Give your iPad a Static DHCP (ip address) you can do this in the DHCP reservations section on your wireless settings somewhere.
- best to keep the bands to Auto or Default.
I had to do this setup for my iphone, specifically the static channel.