Help Radio interference when charging

bmxdad

Member
I noticed something on my way home from work today. When I plug in my car phone charger, my radios reception goes out the door. Unplug the phone and it comes back. Anyone else have this issue?
 

PSkeptic

Android Expert
Broadcast FM or AM?

If it's AM, it's to be expected. You can snap some ferrite beads on the charging cable, and see if it helps.

FM band? I'd be shocked, but not entirely. Same fix: Ferrite beads.

If the ferrite doesn't help, you might need to add a filter capacitor across your alternator leads.
 

PSkeptic

Android Expert
AM? They still broadcast that ... :)

Yes FM, and its not engine related.

Well, it sorta is.

By plugging in the charger, it's now part of the electrical system. Chances are, the ferrites will take care of it, but it doesn't; then the problem is the charger creating harmonics from the engine electrical noise already there.

And, the product of those harmonics is: FM Band interference.

To take care of it (If the ferrites don't), then the filter cap across the alternator most likely will. If it doesn't, well, you might end up needing to reroute power lines away from the antenna lead.
 

bmxdad

Member
Thread starter
Well, not this engine. Interference is there whether the engine runs or not.

Thanks for the suggestions though ...
 

PSkeptic

Android Expert
Well, not this engine. Interference is there whether the engine runs or not.

Thanks for the suggestions though ...

Let me know if it works (The ferrites). I constantly am helping people battle RF noise from a wide array of sources (From Plasma TV's to wall warts, VLF-UHF) :)
 
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