Wow - lots of good info in this thread. Most of the free HD channels in the DFW area are broadcast in the UHF frquency. You only need a simple UHF antenna to receive these. I use the Zenith Silver Sensor and it works pretty good. Its a directional antenna thats shaped like an arrow head.
Most HD satellite receivers have the ability to recive free HD TV also referred to as Over the Air (OTA) programming. You just need to hook up the UHF antenna and have the unit rescan for available channels. Once scanned, my channel line up adds a .1 to each local channel to denote its HD equivalent. So I have channels 4, 4.1, 5, 5.1, 8, 8.1, etc Each of the .1 channels is the HD feed of the current analog channel.
2003 Infinity G35
2001 1100 Shadow Sabre
1996 Sea-doo Challenger jet boat