You look at this website which has specific information for Oregon Active Duty Military.
https://www.oregon.gov/DOR/programs/individuals/Pages/military.aspx
From this site it says:
"Residents stationed outside Oregon
You're a nonresident for Oregon tax purposes if you meet all of the following requirements:
- You didn't have a permanent residence in Oregon for yourself or your family during any part of the tax year.
- Your permanent residence was outside Oregon during the entire tax year.
- You spend less than 31 days in Oregon during the tax year.
You'll only owe Oregon tax if you had income from other Oregon sources. If you have to file a return, use Oregon Form OR-40-N."