Bad earth on cigarette socket?
 

Hi all,

I think I know the answer here, but thought I'd throw it open before I start tinkering and testing.
If I plug gadgets into the cigarette lighter socket (mainly the ignition switched one on the driver side) I tend to get very poor radio reception or a whine coming through the radio speakers.

My suspicion is a poor earth either on the radio or on the cigarette lighter socket, so at the weekend I'm planning on taking the panels apart and check the cabling for the socket, see where it goes, what it anchors to, etc.
But if anyone has had the same and solved it, or at least found the wiring anchor for the socket it'd be appreciated.

I'll post back on what I find, locations, cables, etc, for future reference.

Cheers,
Andy

HiYa Andy lad. You are electronics so this will help.

Morning m8,

Spot on, that was the bit of info I was after as I knew there was more to it than initial thoughts. Will do my reading and see what I can sort out as I've spotted quite a few posts similar to this with the similar poor radio reception or noise through the speakers.

Cheers.

Thought I'd put a bit of an update on here for the archives.

I had a bit of time today, so spent it trying to resolve this problem, confirming that this was an issue with lack of FM reception when the USB charger was connected to any of the cigarette lighter sockets in the GV.

I tried a few things, I setup a new earth connection, running straight from the battery (on a long wire to test) and fastened this straight to the radio chassis, no difference. Also connecting this straight to the ground/outer of the aerial cable at the connector into the radio, same problem.

I'm now thinking that it's got to be the USB charger itself, and I suspect it's a DC-to-DC rf noise problem rather than ground loop, etc (After reading up as pointed in the right way by QinteQ).

Therefore my next steps are to look into the usb charger, I'm going to try the cheap and easy method first and fit some ferrite core's around the short usb charge wires, see if that helps suppress the noise. Otherwise I'll probably end up taking the usb charger apart and see if I can re-manufacture the circuit to be a little less noisy.
Will keep you all updated on the solution (when I find it!)

Spinning something is always indicative when pitch rises with revs, constant pitch when revs rise is usually ground loop, however if it disappears with a CD playing its not wiring or conversely if it never disappears even when a CD is playing its ground loop induced.

Cheepo DC-DC converters are a well known cause when they drop the v from 12 to 5 because switch-mode regs are known to generate both conducted and radiated [RF] noise. Is it all frequencies & bands that you hear the noise. Does it only happen when you plug anything into the socket or a specific brand phone. If you took a supply straight from the battery, and its still doing it then its a safe bet that [earth loop coupling between the high current battery charging circuit and the lower power auxiliary circuits] the alternator is the cause, 'alternator whine' is particularly difficult to remove.