continously losing internet connection - wifi?

hey,
i'm having some serious trouble with my new netcomm wireless router. it
connects normally, and it works for a short time - and provided its not
idling, it will keep the connection. however, when i leave it for a
period of time, it appears to disconnect and reconnect me. this is most
obvious in my IRC client mIRC, which displays the regular error:
Software caused connection abort
i am using a netcomm NB5540 wireless router.
the settings (aside from the obvious things, such as SSID) are set to
default.
any help is appreciated