help with OTA in orlando

I live in Orlando, FL 32828. I know exactly where the transmitters are. I am within 10 miles of them, and have a Terk HDTVi indoor antenna. It drew in all channels 100%, but now I have it in my Dish ViP211 and it is only picking up 90% for everything except ABC. ABC is 70%, and at any fast motion sequence COMPLETELY drops out. I've been recommended to use a better coaxial(quality with antenna isn't good), but I believe it is hardwired to the antenna. I'm thinking about a pre-amp, but I'm not sure. Anyone know?

Have you replaced it? And I'm trying to figure out how the other antenna is better. I heard the ViP211 has a great tuner. But if its 30% difference better, it scares me. should i get a pre amp or what?

well, im now getting 95% wftv. but wofl is down to 73% and drops out. gah, this is sooo annoying!