Interference on AM band only from portable fridge

[Lorgar]

This is a strange one to me... I've got my new portable fridge in the boot, currently running of the cig lighter socket in the rear (soon switching to aux battery).

Strangely when the compressor is running the volume of the AM band on the radio is reduced and there is quite a bit of static. Only on the AM band though, not on FM or on CD.

I'm familiar with alternator whine effecting systems but never heard of it interfering with one band only?

Any suggestions on cause/solution?

[taffy4x4]

Hi Lorgar, it;s something to do with the way the AM radio waves are produced, to stop it you should be able to buy a noise suppressor from any good audio place.

[Supaduke]

Have a look at ferrite noise suppressors. Pretty cheap and just snap on. I had an issue with my computer speakers affecting the tv. Snapped a few ferrites on and cured the problem instantly.

[deye243]

it is because amplitude modulation if far more susceptible to interference than frequency modulation

[Lorgar]

I've got a few ferrite clamps somewhere, I'll dig them up. Cheers.

Also, initially just to muck around with the fridge I had it plugged into the lighter socket on the back of the console for passengers.

I've just had my aux battery installed yesterday with a line run to the boot. I'm headed out today to test for the first time off that, so I'll see what happens.

Failing that, dig up a suppressor.

[Lorgar]

So much ado about nothing in the end.

When running the fridge off the newly installed sockets in the boot from the auxiliary battery there is no interference.

Solved itself