Many younger Americans who grew up with cable TV and streaming don’t realize there is still a free, although limited, alternative with over-the-air antennas that capture broadcast signals without a connection to a cable box, satellite dish or internet. E.W. Scripps, the Cincinnati-based media company that owns 61 TV stations nationwide, is spending $20 million this year on an education and marketing campaign to help consumers understand the use and benefits of over-the-air antennas. Scripps launched a website — TheFreeTVProject.org — where users can type in their ZIP codes to learn what stations they can get for free in their area with an antenna.