I use the little RCA digital antenna from Walmart. It's flat, about 12" square and does one good job. I bought it when I was in my truck and use it at home now. I live in the country, 50 miles from Chattanooga and 70 miles from Knoxville. I pick up all their stations, about 20 channels. Places like Dallas, Chicago, NY, LA you can pick up 40-50 channels.
They have a more expensive one, but this one does just fine.