Radio interference when I turn on rear defroster.

boostjunkie · Post by **boostjunkie** » Thu Jan 13, 2005 2:49 am

Hey guys. Just started listening to the radio in my car this week (yeah, I don't listen to the radio too much) and noticed that when I turn on my rear defroster the radio signal gets REALLY weak.

It's a rear mounted antenna (might be amplified, not sure) so I'm assuming the antenna's picking up interference from the power wire for the rear defroster.

Any other possibilities?

The only solution I know of right now is to reroute the rear defroster power or antenna cable.

vrg3 · Post by **vrg3** » Thu Jan 13, 2005 4:31 am

Hmm, I wonder if there's a bad ground at the antenna. The defroster probably also grounds in the same area. This is just wild speculation, but maybe when the defroster turns on, it causes a DC bias in the signal from the antenna because of the voltage across the chassis.

Maybe to test out my theory you could try using jumper cables to connect the negative battery terminal directly to a point on the chassis near the antenna base?

Post by **Legacy777** » Thu Jan 13, 2005 4:04 pm

Try adding an additional ground to the stereo ground lead.

Typically stereo noise/issues are caused by poor grounds.

boostjunkie · Post by **boostjunkie** » Fri Jan 14, 2005 12:27 am

So you're both considering it to be a grounding issue. Seems logical enough. I'll probably run a larger ground back to the radio directly from the battery, just to be safe.

magicmike · Post by **magicmike** » Fri Jan 14, 2005 1:29 am

boostjunkie wrote:So you're both considering it to be a grounding issue. Seems logical enough. I'll probably run a larger ground back to the radio directly from the battery, just to be safe.

dont do that....I dont think thats the problem. I'd be willing to bet its the ground where the anttena is mounted. that area usually corodes a little and the antenna will try to pull its ground through the radio ground. In case you didn't already know the antenna wire is like a coax cable with a shield being the ground. good luck

boostjunkie · Post by **boostjunkie** » Fri Jan 14, 2005 1:41 am

So how does one reground the antenna, assuming that's the problem?

I'll try the jumper cable idea tomorrow.

magicmike · Post by **magicmike** » Fri Jan 14, 2005 11:24 pm

the antenna gets it ground from the hole it goes through. You have to remove the antenna and clean it up good and reinstall it

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Radio interference when I turn on rear defroster.

Radio interference when I turn on rear defroster.