I recently bought a Honda Accord EX 2004, and have the 3 month free trial of XM. At the end of the 3 months, I would like to keep XM but instead of having it be in the car stereo, I would like to use one of the portable units, so that way I can take it into my house as well. I was wondering if it would be possible to use the existing antenna that is on the roof of my car and attach it to a portable XM unit. I would really hate to have two XM antennas on the roof of my car. -Jay ()