Dropping Belkin F5D7000 using F5D7633

Hi,

I am using a F5D7000 with a F5D7633 router (wirelessly). Periodically the
connection between the PC and the router drops, for no apparent reason. It
appears to be worse when the internet is not being used (as if the data flow
when it is in use somehow keeps it "alive").

The F5D7633 is connected by wire to another PC. Both PCs run XP, one home,
one pro.

The signal strength is between 70%-85%, is this not strong enough?

I am unaware of anything that could be interfering. We have a DECT cordless
phone, but there is no correlation between it being used and the dropping.
Im in a rural area so it is unlikely interference from a neighbour's wifi.

I have tried channels 1 and 11, would others be better?

Any other ideas would be greatly appreciated.

Chris