On Wed, 5 Nov 2008 17:36:26 -0800 (PST), Mark
wrote:

WHEEL STATIC ONLY ON SOME PATCHES OF PAVEMENT? WHY?
With the financial mess, I have started to listen to AM radio in the
car on the way to and from work for the past few weeks and I've
noticed some random static at certain locations. At first I
attributed this to some power line noise. Bit it didn't really sound
like 60 Hz buzz hash, it was more random popcorn like but I know power
lines can blow around in the wind and have strange discharges so I
didn't think too much of it for a while. But after a few days I
noticed that the static is there only when the car is moving. OK, so
its wheel static. Static electricity from the wheels or brakes or
something. OK that's not unusual either. But it is the combination
that has me curious. This static only occurs when the car is moving
and it only occurs at certain repeatable locations on my drive.
Everyday when I turn the corner from X to Y, I get the static as the
car is moving, but not when stopped at the same corner. And I never
get the static when turning the corner from A to B. If it was power
line, stopping the car wouldn't stop the static. If it is wheel
static, why does it not happen all the time and happen only at certain
locations.

Question: you say the static only occurs when the car is moving and
gave two scenarios where the car is moving: turning the corner from X
to Y (with static) and A to B (no static). My first question is are
these right turns, left turns or one of each? Is there a traffic light
at one and not at the other? Do you hear the static when driving
straight or performing the turns in other locations? Two theories
he 1)is that maybe when you turn, something is coming into contact
with something else completing a circuit (or alternately seperating
and breaking a circuit) that would result in your static and 2) if
turn X to Y and A to B are at different intersections, there might be
something in the environment at the X to Y intersection that may not
be present at the A to B intersection - such as a traffic light and
its sensors and controllers, a business's sign etc...

My second question is have you tried the static producing maneuver
with the radio turned off? Just curious as to if the source of the
noise is from the sound system or maybe from another source that you
may not have noticed before you started listening to the AM radio -
car bodies and panels can flex some when under g loads like turns and
that could be the source of your noise.
--
"I... Can't drive... FIFTY-FIVE!!"
--Sammy Hagar