The Duluth stations are going to require some extraordinary measures to insure good reception in your location. The stations are 50 miles away, and the signals are weak in your area. You really need a deep-fringe solution for both VHF and UHF to insure decent reception. Duluth has 2 VHF digital channels, and a UHF-only antenna won't give you what you need.
I suggest my deep-fringe prescription: a Winegard YA-1713
VHF high-band yagi and an AntennasDirect XG-91 UHF antenna mounted on the same mast. The XG-91 should be mounted on the top of the mast, and the YA-1713 should be mounted 4' below it. You should use a preamplifier, especially if you plan to run multiple TV sets from the antenna system. I would use a Channel Master Titan 7777 preamplifier, which has terrific gain and has separate VHF and UHF inputs, making it easy to connect separate antennas. Aim the antennas due East, and connect them to the proper input on the preamp. before connecting the preamp, you will have o open the preamp up and slide the 'combined'-"separate" switch to separate, so the preamp will recognize both antennas.