OTA HD in SE Minnesota

Hi - I'm a more active poster in the DTV forums here at DBS, but this is my first visit to the OTA section. I have a question that I think this forum would have more expertise.

I live in Rochester, MN which is 85mi SE of Minneapolis, St. Paul. I have had a lot of luck with my OTA set up except on channel 5.1, the ABC station. The signal can range from 10% to 60% causing constant break up, while most other stations from the cities are constant 50-80% on the same line of sight and distance. There is an ABC station that is 40mi away in Austin, MN but they don't broadcast sports in HD yet.

I use the following antenna, I know it's not a channel master, but the range is great:

http://www.radioshack.com/product/index.jsp?productId=2103088&cp=&origkw=antenna+uhf&kw=antenna+uhf&parentPage=search

Then I use it with an amp that I also got from radio shack that cost about $55. This one:
http://www.radioshack.com/product/index.jsp?productId=2103094&cp=&origkw=antenna+amplifier&kw=antenna+amplifier&parentPage=search

My set up then is as follows, there is a 3ft cable from antenna to the pre-amp on the pole, then about 75ft to the inside of the house, where the wire connects to an amp, from there I us a 1ft line to a splitter to go to 2 TV's because I have DTV and not HD locals. One TV has a 3ft run, the other is about 50ft. Most of my wiring is this kind, also from Radio Shack:
http://www.radioshack.com/product/index.jsp?productId=2062070&cp=&pg=1&origkw=100+rg6&kw=100+rg6&numProdsPerPage=50&parentPage=search

What can I do to better pull in the signals from the cities more consistantly?