Try
www.KEXP.org.
It's the U of W. station.
I don't know if could reach Portland, but it's the only 90.3 in that area.
Also check out live365.com, you may find it there.
Most college stations play alternative.
Are you sure of the freq?
KGON at 92.3 is a classic/oldies station in Portland.
GO PANTHERS!!