I'm trying to sort out the usage of a Scala Rider Q2 headset with my Garmin 2730 and iPhone. The Scala pairs with the 2730, and the iPhone pairs with the 2730 and all works great. I can make and receive calls with no problem and hear the GPS directions. I also have a GXM30 but can't get XM through the Scala even when using the hardwire between it and the GPS.

I also have an electronic hum and think I know that it takes a ground loop isolator, where does that go and where would I get one?

Any ideas appreciated.