Bad RF radiation in car. - AVS Forum
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post #1 of 8 Old 04-28-2012, 06:20 PM - Thread Starter
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I tried asking this in the car audio section awhile back but no help. I have a 1990 Cadillac Seville (mint) that is frustrating me to no end with RF radiation coming from the motor and/or the computer. When running, and at medium to higher volume levels, the sound has a "pulse" to it. In a way like talking through a running fan. No matter if it is on AM, FM or CD. With AM and CD, I also get a very high frequency whine. In the 14-20 kHz range. When the engine is turned off, the "pulse" goes away but, the HF whine continues but decreases in frequency like it is winding down. If I turn on some computer related function with the motor off, the whine gets louder. This has happened with several decks so I don't think that is the culpret.
Please help me!

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post #2 of 8 Old 04-28-2012, 07:12 PM
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The standard practice is to put an inline filter on the power to the unit and see if that fixes things. Are you handy that way? If not, I would take it to the local car stereo shop and have them sort through it.

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post #3 of 8 Old 04-28-2012, 09:27 PM - Thread Starter
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I could put on in. That is not a issue but, what kind of filter? Is it normal for this "noise" to come through the power supply? This is the only car out of eight I have had trouble with!

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post #4 of 8 Old 04-28-2012, 09:59 PM
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Yes, it can happen and happens often. One thing I forgot to mention is to make sure the unit is well grounded. That often causes such noises to bleed.

The type of filter you need is listed here: http://www.crutchfield.com/S-ZCUK2aS...e-Filters.html

Try to find a local source though (e.g. Radioshack) so that you can return it if it doesn't work.

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post #5 of 8 Old 04-28-2012, 10:03 PM
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Short answer is: Sell the car. Serious! Cars electricials noises are tough to diagnose.

If this happens only when the motor is on, I would diagnose this as "alternator wine" but if u have trouble even with motor off, man, u gotta new decease there I've never heard of. Only thing I can offer is, suspect after-market installed alarm system and/or remote start.

Best of luck!


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post #6 of 8 Old 04-29-2012, 08:35 AM
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The best thing to get rid of this problem is ferrite inductive filters, which you can get from Radio Shack and install. (#273-105)

They are very simple to install; they just snap around the various power wires of whatever device is giving you trouble. They will suppress any RF in the wire. If needed use 2 or 3 on some wires.

Also, make sure that the equipment in question is actually grounded to the frame of the vehicle, not just some sheet metal that may not be well-grounded.




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Originally Posted by karlsaudio View Post

I tried asking this in the car audio section awhile back but no help. I have a 1990 Cadillac Seville (mint) that is frustrating me to no end with RF radiation coming from the motor and/or the computer. When running, and at medium to higher volume levels, the sound has a "pulse" to it. In a way like talking through a running fan. No matter if it is on AM, FM or CD. With AM and CD, I also get a very high frequency whine. In the 14-20 kHz range. When the engine is turned off, the "pulse" goes away but, the HF whine continues but decreases in frequency like it is winding down. If I turn on some computer related function with the motor off, the whine gets louder. This has happened with several decks so I don't think that is the culpret.
Please help me!

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post #7 of 8 Old 04-29-2012, 09:27 AM
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First thing I would do is check (or, have someone check) the grounds on the radio and everything else, too.

I've started getting some alternator whine and other noises in my AM radio (2000 Subaru). I noticed that there was a (apparently) burned out light bulb in the dashboard, by the heater controls. I had the dealer check for a problem with the noise/grounds and the alternator, but forgot to mention the burned out light. A few days later, I had to switch from A/C to heat again, and pushed the slider hard...the light came back on!
Slapping the side of the console makes it come on and off, and the radio noise level changes, too.

Sounds like I'll need to pop open the side panel on the console, and see if there's a loose wire. If your noise is getting in to everything, though (not just radio), you might also have the alternator checked.

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post #8 of 8 Old 05-01-2012, 09:57 AM - Thread Starter
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The grounding issue has my curiosity. So does the alternator. One thing I noticed with AM reception is that when I apply the brakes, the noise deminishes. Not completely however. I will look into this stuff.
Thanks!

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