If a few buck invested in a small or mid size UHF antenna can be risked... go for it. But before committing $$ to that option you'll want to look into which translators are on the air.
Fox tends to be a big football outlet (at least here in the Seattle market).
http://www.rabbitears.info/market.ph...n=KPTV#station suggests their translator may not be on the air at the moment.
I also don't see a translator that caries an ABC network feed in Rainier.
I would lean toward going after the Portland signals.