Wireless connectivity outage

Hi everyone,

I have a Linksys wireless G router, three machines connected (one wired desktop, two wireless notebooks). It is set up as an mixed infastructure network, open authentication, no WEP, channel 11. I am operating from behind a firewall, running XP on all machines. One machine has a 3rd party Linksys card (802.11g) and the other an internal (also g).

For the most part, everything works fine for weeks at a stretch- then, I will get entire days where both machines that are connected wirelessly cannot hold a connection for more than a few minutes at a time. The lack o' connection lasts from a few seconds to a few hours. The machine connected via network cable is of course not affected. In the time it took to type this, I have lost and regained my connection three times.

The way I am currently dealing with each outage is to go to the wireless connection properties and hitting refresh until the network shows up again, then going in to the connection status to ensure the address is valid and repairing if necessary.

Any thoughts on what may be causing this and/ or how to go about fixing it? Any help is appreciated, as I have tried everything to the extent of my (limited) knowledge!