My first thought exactly.I don't have a password lock on my wi-fi, but I live down in a dip so my range is very limited. Also, there's no light activity on the router when it's not doing something that I have initiated on the iPad. I have the latest OS 3.2.2.
I did a hard reset this morning but that didn't help. I think I'm going to try to borrow a router from a friend and see if that's any different...but then again I don't understand why something that worked well for 2 months is now not working so well.
Always set a password. It doesn't matter what you think the range is, you could easily have someone leeching you!
How are your computers doing, are they slow too?Interesting about solar activity! Are you now experiencing the wide and quickly changing wi-fi strength issues like I am? And if it is solar activity induced, how long do those periods where it affects radio signals generally last?
Other wireless devices in your house could cause interference. Have you bought anything new? Relocated a cordless phone base, moved your router? I think microwave ovens can even be a problem with wifi.
I'd also like to add to what others have have said about securing your wireless network. These days that is just announcing that you are the neighborhood hotspot. People will be using your bandwidth.