You people know you can get over-the-air HD signals of all the major networks for free, right? OTA HD is actually a better picture than HD via satellite or cable, it's not like in the days of rabbit ears.
This site will tell you the best direction to point an antenna for digital reception:
http://www.antennaweb.org/aw/Address.aspx
A ballpark figure for Shreveport/Bossier is to point it towards Oil City.