Alternator Noise

My carrier hooked me up with a brand new 2021 Cascadia. So I'm having to install my radio all over again.

I spent several hours yesterday routing antenna and power wiring through the driver's side of the engine compartment and behind the dash to come up through the center of the dash. I made sure it was all very clean and organized. Coiled the excess antenna wire into a figure-8. Power comes from the battery (soldered in-line 15 amp fuse close to battery) for both my radio and West Mountain Radio ClrSpkr.

Sadly, I have even more alternator noise now than when I had it powered through the fuse box in my last truck (2018 Cascadia). At least, I think it's alternator noise--it's a whining noise that increases in pitch and volume with increase in RPM.

The body is all fiberglass. Not sure where I could hook up grounding wires that would actually accomplish any good. I also have several ferrite chokes that go around the power wires. They've never helped, but it's more work to take them off and they didn't seem to make the problem worse, so I left 'em on.

I would really appreciate any suggestions here.

 

Thanks. I've never dealt with an isolation filter. Could you elaborate?

 

I'll give this a try. Thanks!

 

Cobra 29 LX

I've got some straps. Just haven't found the time to do it or thought it places to try it on. Other than at the door (body is all fiberglass), where else would you suggest?