Unfortunately, AM radios pick up all kinds of interference from you engine.
The two
main culprits are the ignition system and the charging system. The
alternator will cause
a whine and the ignition will produce a rapid ticking sound. Both increase
with engine
speed.

When did the problem first occur? Had you done any maintenance right before
the
problem started? If so, things like spark plugs & ignition wires may be
causing your noise.
Most European cars use ignition wires with resistors built into the ends.
Check resistance
with an Ohm meter and compare to the spec on the wire end. Old wires may
have degraded
resistors or even new low quality wires can cause a noise problem.

If your problem is truly just static, the problem may be with the
radio/antenna system.
Make sure the antenna is fully extended and securely connected and the head
unit is properly
grounded.

Good luck

R. Scott McKernon
Store Manager
Olympic Auto Parts
9136 Gaither Rd
Gaithersburg, MD 20874
1-800-472-9360
olygburg@covad.net
www.olyparts.com

I'm taking me new M5 in for service with the same complaint. The reception
of the"All News" AM station that I like to listen to is soooooooo bad that
it fades and crackles when I drive down into a small valley in the road.
It was way better on my 87 325, and in any of the 4 other cars I have.
I think the problem is the crappy imbedded antenna - hopefully there is
something wrong with it and not something that can't be fixed.
I'll post again when I get some results.

Antenna Pre-Amp.  Or, a crack in the diversity antenna.  I unfortunately had
a similar problem with my '01 330xi's am/fm/cd; fix was a new unit (under
warranty, thank goodness.)

This is a very common problem with BMW's radio.

BTW, have you ever noticed that the AST/DSC interferes with the AM?
This won't change even if you get your problem fixed.

Floyd

I had a problem with the antenna connector at the radio.  The center
conductor
wasn't connected, just close.  Enough for FM to couple across, but not AM.

I just had to put a new connector on.

   John

RFI interference was apparently a common problem on early E46 models.  The
fix for my '99 328i was a warranty replacement of the antenna amp.  However,
my problem was moderate interference - a rev related whine which was
noticeable only at low engine speeds as when idling at a stoplight.  Good
luck!

Tom

I learned the hard way that tinting a window that contains the antenna can
seriously limit the antenna's performance. Most commercial films are
metallic, and will affect AM radio. I switched from metallic to non-metallic
and the results were improved reception. I live in a rural area and our AM
reception is poor to begin with, but with the metallic film is was next to
nothing.

If you're still having this problem, I had similar problem on my 99 323i,  
and apparently it's quite common for our cars.

The noise is sensitive to speed; If you're going slowly through a low
reception area, you'll hear click-click-click sound through the radio,
the faster you go, the quicker the clicks become. if you're going >30mph,
the clicks become a constant whine.

If that's the problem you're getting, the fix is really simple.
There's an antenna signal amplifier behind the panel of the driver-side,
rear column. just pop out that cover, check all the connections to make
sure they are TIGHT. Use pliers to screw in the coax cable if you have
to.

There's a nice HOW-TO page on the web describing this problem with
pictures and everything. I don't have the link, but you can search for
it. Good luck.