FM static after radio change out 02 Seville

Any insight on an installation problem I have with a 2002 Seville might help. My only remaining issue is a crackling noise in the FM band. The car didn't come with a Bose system so I changed it out with Alpine CDA-9833 and JL e6450 amp, BA Pro speakers. All quality components. The origional head unit is still mounted in the car in the trunk to keep the Class 2 communications, OnStar and the chime alarm system working. Origionally the installer didn't hook a "power" lead to the antenna module and I had FM (clear and no noise) but could not recieve AM. He then connected the power lead to the antenna module and now I have AM & FM, but the FM has a "crackling noise" (kinda sounds like popcorn in the way it comes and goes) on almost all stations, although it does vary a little. It is most annoying. A local shop here suggested something about differential in the grounding of the components as creating the noise. Has anyone had any experience with this before or any thoughts, suggestions? Any ideas of help would be greatly appreciated.

Bet it's either a ground.

Does it make this noise when on the ACCY setting? (Engine not running) If so, then it only points more to a faulty ground.

Try this. Take an alligator clip, and clip a good clean piece of steel under the dash, then clip the other end to the body of the new radio unit. Make sure you're getting good contact, as you want the best possible ground you can make. If the noise clears up, it's certainly a grounding issue.

If you still get noise with the engine off, the antenna disconnected and a known good ground, return the radio to the store and make them check the unit. It could be an ground internal to the unit. (Broken wire, trace, bad solder joint, etc.)

Now, I'm assuming whomever installed this radio used proper connections, no "twist-n-tape" stuff where it could be speaker or hot leads rubbing where twisted together, which also can also cause a "static" noise.

~~R.Banks