This has been asked but a definite answer has not been given. Can you used an Sirius antenna for both XM and Sirius reception. For example, if I have both in a 2008 Dodge Ram, which has the factory Sirius antenna, can i get a splitter (or if necessary, splice wires) to make the factory antenna work for both. Or is the Sirius antenna just not compatable with XM. I have both in my truck and would like to get rid of the XM antenna on the roof and use just the factory Sirius antenna.