I have been having the exact same problems with both wireless and wired connections.
Changing the channel and setting static IP addresses and increased lease time to 20 days has fixed the wireless issues.
However, the connection to the internet still keeps dropping. Wireless devices stay connected to the hub but lose internet. Wired devices also lose internet.
It seems that this is a problem with the hub itself and best advice I have seen on here is to buy another hub. I take this as a job for Trading standards and BBC Watchdog as BT adverts all state that this is the most reliable internet ever.
This will of course hit the BT shareprice when news of the hub problems is made more public as BT owe us all a better hub.
I will be asking for a full refund of all costs to date and move to Virgin Media.
Welcome to this customer to customer forum. Your problem sounds like an ADSL connection problem.
To enable forum members to help you, please could you look at Helping forum members to help you which asks you to do a few checks first, and has some helpful hints. When you have done that, please post the results here, so members can offer advice. Thank you.