That is an awesome antenna. I hope you enjoy it as much as I have. Now let me see if I understand what you're asking:

You want to use the ST-2 in conjuction with the antenna supplied with your tuner/receiver? And you want to run both to a shared cable via a splitter?

Also, how did you arrive at the location for your ST-2? Did you randomly pick a spot on your house, or did you try various spots trying to optimize reception?