I'm a BT openreach engineer and i have seen issues like that before when visiting customers, In the router setting there are 11 wireless channels and it will always pick the next one, if you go into the setting you can actually allocate a channel to the Xbox, all the channels have a frequency, it's probably another electrical device given off a simular frequency causing interference. Just allocate channel 11 to the Xbox and all should be ok.

To access Hub Manager just open up internet explorer and type 192.168.1.254 in the address bar and it'll access the Hub, you'll need the Admin password which is on the back of the Hub, if you have accessed it before but can't remember the password just push the small Default button on the side of the router for a few seconds and the original password will work. I can't remember exactly how to allocate a channel but it's not hard..

Hope this helps

Ginger