I had similar problem and initially suspected ubuntu or the netbook for it. But the culprit was the router.
Had D-Link router which was causing all the issues. Bought a Linksys router and signal strengh went up and didn't face any issues after that. Rarely a few times disconnected by quickly connected back. I would advise please check your router. If you have a spare try with it.

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I'd exclude router problems because 3 other computers connect perfectly and they never disconnect. When windows was running on this netbook it didn't disconnect too. I think it could be a drivers problem
- Visitor 2 years 11 weeks ago