Portland is 5 hours behind Brasília
Best overlap: 1:00 PM to 6:00 PM in Brasília is 8:00 AM to 1:00 PM in Portland.
For the smoothest call, aim inside 1:00 PM to 6:00 PM in Brasília, i.e. 8:00 AM to 1:00 PM in Portland. A 5-hour overlap gives you a workable daily window; aim for earlier in it to avoid clipping the end of someone's day. Seasonal note: Portland uses daylight saving and Brasília doesn't, so double-check the times in your own months — they can move by an hour.