Audio Systems: car stereo whine, pitched whine, dash unit

Question
I have a satellite radio plugged into my aux port on my car stereo and it has a constant high-pitched whine.  The guys at Circuit City told me it was because the satellite radio is a power source and there's nothing I can do about it unless I get the satellite radio in-dash unit.  Surely there must be something I can do.  I can't be the only one with this problem and it is intolerable to listen to.

Thanks,
Chris

Answer
Yes, the whine could be coming from the ignition system in the car.  Does it go away when you  turn off the engine?  Does it go to a higher pitch when the engine rpms increase?

If so, the noise is ignition based and you must obtain some ignition filters for your car.  Car parts places can usually supply you with such devices.  Crutchfield.com also carries them.

If the whine is constant pitch and just remains the same does it go up and down with the volume setings?  Or does it remain constant always?  If it is constant it is rfi getting into the power amp. If it goes up and down with volume it is coming from in front of the volume control on the stereo set.  

And, you might check with the supplier/manufacturer of the sat unit; they may have a filter accessory for it.

Let me know how it goes or if you need more.  I haven't had this complaint at all and I am interested in what you find out.  Thanks

C