- even when I lose the link the signal indicator that WinXP provides stays at 100%
Sounds like multipath reflections. Moving the base station a few metres might make a big difference.
I use an access point, do all devices have to be able to "see" the access point at all times or do they fall off the network when they can see other devices but no the access point ?
In "infrastructure" mode they do need to see the base station.