I have a King antenna that is at least 10 years old. Reception is not great. Would there be much improvement if I purchased a newer model, the King OA8300
As suggested, the best reception would be seen by installing a Winegard Sensar 4 and a SensarPro power injector/amplifier. With many stations moving from UHF channels down to the high and low VHF channels under the FCC repack rules, the Sensar VHF performance is much better than the King.
I had pretty good reception (50 miles over flat land) with the old Winegard with the Wingman add-on and a Sensar Pro booster. The new Winegards have the Wingman attached.