The one distinguishing characteristic of the DTV SWiM splitters is a very low isolation between output ports, necessary so that the MOCA protocol will operate. This is the opposite characteristic from what is desired for OTA and cable signals.
Since you already have it, go ahead and give it a test drive. If it works fine, you're done and it will work okay in your specific situation. If it doesn't work correctly, run down to Home Depot and buy an Ideal sat-rated splitter
http://www.homedepot.com/p/Ideal-2-4...-334/202276266 It has the added advantage of having steering diodes internally that allow ANY of the output ports to power your pre-amp, greatly simplifying installation.