Radio Noise

[Barnum]

Perhaps I am naive, but what causes static on certain AM stations, that increases as you step on the gas. It happens in certain areas, and only at various times...???

[LadybugEwa]

I have this same sort of problem, only it's to the point that my AM is noting but static. It also seems to be related to my headlight bulbs , since AM radio comes back as soon as those burn out . Since every mechanic I described the symptoms to told me it was impossible, I decided to treat it as a personal hallucination I'd love to see what the mechanically-inclined org-ers have to say about that.

[Toad]

It's electronic interference in the lines. There's not really much you can do about it.

[cyberbeetle]

I believe that grounding the radio itself to the body might help.

[from Margaritaville...]

Some factors that can cause variable interference on AM stations can include the use of non-resistor type sparkplugs, installation of non-factory recommended ignition wiring and even the re-routing of spark plug wires...

[Barnum]

Why then is it only in certain areas of town, and not every day? No big deal, but pretty annoying when I am listening to something special, and it starts up...

[XCman]

it's the nature of the analog radio signal AM uses. Unlike a digital signal which just cuts out when signal starts to get worse. Radio is in the form of a wave. And when the wave isn't entirely smooth you hear the audible interference.

AM is way more suseptible to interference than FM because it's a much lower frequency. AM is at 1,000's of hertz where FM is 1,000,000 of hertz. The lower the signal the wider the radio wave it makes. the longer the wave the less information in sound the radio can produce per second. The more Waves a radio recieves the stronger the signal. AM just broadcasts at much lower waves. Thus making lighting, electric lines, magnets in your altenator, to the rubbing of metal in your cylinders all create a small bit of electronic resistance. That last bit won't be noticable in your radio as it is very very minute. But anything electric especially your altenator will creat lots of interference. And the faster you go, the more electricity and magnetic interference your alternator makes.

They make noise filters for your radio to reduce this.
http://www.crutchfield.com/S-gDdGZKI...asp?I=003AS100
but what they say about rerouting your antenna wire will help the most! or replacing it with one with better insulation to prevent interference.