Megaman. 1. 2. 3. Viewers who get their favorite shows for free by using over-the-air antennas have made "OTA" the buzzy acronym at the Internet & Television Expo being held this week in Chicago, where cable companies are gathered to mull over their fast-changing future. There are now more than 12.3 million homes that depend solely on over-the-air broadcasting for their live TV viewing, a net gain of 1 million over the last year, according to audience measurement service Nielsen. That's about 11% of all U.S. households with TV — hardly a mass migration to the old-school technology. But as the cable and satellite industries see a downward trend in the overall number of customers signing up for their video offerings while broadband Internet service continues to grow, it's getting more attention. Some homes are turning to over-the-air signals because they can't afford cable.