2002 jag x-type

I installed the first XM radio FM prototype as well as the first consumer XM system in the U.S.  What I have discovered with FM-mod systems is that you must be careful of two things:

 

1) If the antenna is electronically boosted, such as many late-model VWs,

 

2) And the adjacent channel selectivity of the radio.  This means, whatever frequency you want to broadcast the satellite unit on, try to get a channel that has NO bleedover from other stations.  You want a clean static sound.  The FM mod needs to be OFF when you check this.  In Los Angeles, it is difficult sometimes to find this because there are so many stations here.

 

Back to #1:  If you unplug the factory AM/FM antenna from the modulator, does the problem go away?  If so, it is the antenna causing the noise.  Satellite FM units switch antennas, from the AM/FM to the satellite antenna, and many of these boosted antennas fight for control of the switch.  This is the best way I can describe it.  Often you can just install a rubber duckie antenna under the dash somewhere and pick up decent FM.  It's not great, but most people paying for satellite aren't likely to use those free bands much.