I was going off this:
"First are the NBA’s territorial restrictions, which Miller said prevents the Blazers from broadcasting farther than 75 miles into Washington. Because of those regulations, only three of Portland’s radio affiliates are located in Washington, the most northern of which are located in Longview and Kelso — each approximately 50 miles outside of Portland.
To expand their broadcasts, the Blazers would first have to petition the NBA to allow them to add the Washington market to their territory — a move Miller said the team has not explored, and will not pursue until the Sonics’ status is finalized."http://www.columbian.com/sports/localNews/2008/06/06102008_Regional-Royalty-SuperSonics-departure-for-Oklahoma-City-would-could-turn-Blazers-into-Northwests-team.cfm