Assuming that you have
DTV or Dish network lnbs on the 18" dishes, make sure that you have set the LO freq to 11250. Other than music channels, there are only about 2 signals to watch. Go to Lyngsat,
http://www.lyngsat.com/america.html and find out the freqs and PIDs of signals you want to receive. You can enter these into the VisionDTV or WinDTV program that came with the
Twinhan, but I'd recommend downloading some other programs like
TSREADER
http://www.coolstf.com/tsreader/clients/
DVBAPPS
http://www.dvbapps.com/secure/ and/or a couple other programs.
TSREADER doesn't display video directly, but can feed it to other applications, but I find it really useful in seeing what is available quickly, then I switch to another program to view it.
You can just continue to use the Twinhan program, but it isn't very user friendly.