2011 MDX Elite

Have a Thule installed and my XM signal sucks while driving north. Curious if anyone has pull head unit out. Is there a plug for antenna like a plug and play satellite radio? Can a Y adapter be installed and run 2 antennas. Some help would be greatly appreciated.

Thanks

 

A Y cord on the antenna input will create a drastic impedance mismatch and would make the issue worse.
Unplugging the stock ant and installing a separate alternately located unit may help.