Monsoon XM and Factory Antenna

[KCJohn]

I have a Monsoon 6 disk system and want ot ad XM. If I use a system like the Trek GM XM radio can I attach it up to the factory XM / Onstar antenna? Or does someone make an antenna adaptor (or at least all the parts to make one) that could be used?

There's enough antennas on the truck already!

Thanks

[f5fstop]

You can't use the actual Onstar lead, since it is used to receive GPS signals; however there should be a separate lead that is not connected to anything, and that would be the XM lead and can be used with any XM unit. There may be a need to revised the connector where it plugs into the unit.

[KCJohn]

Would the extra lead (the one that would be used for the factory XM be found where the XM receiver is or do you think that they even put the lead off the antenna block?