I have tried a few different types of 12v 'plug-in' USB chargers, I have an old two port one that seems to work very well without causing any RFI, I do have a couple of other types (hardwired for my camper - it comes as a plate with a small volt-meter, 12v socket and twin USB charger) that almost instantly wipe out FM radio when in use.

I haven't tried ferrites on the positive and negative power lead to these to see if this makes a difference, I just think the switching in these is very bad.

Matty

MD0MAN

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