I bought a Sharp Aquos from Costco. Model LC-40C32U. I was told I could pick up HD channels broadcast locally with an antenna. I tested the antenna theory with a piece of coax, but results were pretty poor. Sharp customer service guy told me that the tv has no HD tuner. The manual lists the following tuners: 8VSB (Digital Terrestrial Broadcast), ATSC (tv standard), QAM (Digital cable) and NTSC (tv standard). Do I have to get an outboard HD tuner to pull the HD signal out of the air? Per antennaweb, I have multiple local HD broadcasts within 6 miles of my house.