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. It seems as if these certain locations have something
special about the pavement or the water content of the soil or
something. None of that seems likely to me though, I see nothing
changing in the pavement as I drive from an area of static to an area
of non-static. It is not related to stepping on the brake or gas or
shifting gears or going over bumps or any other aspect of the car that
I can tell other than it's speed down the road.
As an experiment, I attached a drag wire under the car. The wire
drags on the ground to discharge any static build up the car. This
made no difference. Another clue, we've had no rain here in a
while. The static all stops during wet weather. Also I am in the
Philadelphia area and the AM station is in the New York area so it is
on the weak side.
I've been a ham for over 30 years and I have a lot of experience with
EMI, but this one has me scratching my head. The wheel static
changes repeatably in different locations for no apparent reason.
It's got to be something to do with the pavement. Anybody have any
experience with this?

Mark

On Wed, 5 Nov 2008, Mark wrote:

I've been a ham for over 30 years and I have a lot of experience with
EMI, but this one has me scratching my head. The wheel static
changes repeatably in different locations for no apparent reason.
It's got to be something to do with the pavement. Anybody have any
experience with this?

Mark


My guess is different lengths/types/orientation of rebar in the roadbed.

--
My mailbox is NOT an advertisement medium. Tehrasha Darkon
My address is NOT for sale, lease or rent.
Send me spam, lose your account. Get it? TINLC-1372
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"Tehrasha Darkon" wrote in message
...
On Wed, 5 Nov 2008, Mark wrote:

I've been a ham for over 30 years and I have a lot of experience with
EMI, but this one has me scratching my head. The wheel static
changes repeatably in different locations for no apparent reason.
It's got to be something to do with the pavement. Anybody have any
experience with this?

Mark


My guess is different lengths/types/orientation of rebar in the roadbed.

--
My mailbox is NOT an advertisement medium. Tehrasha Darkon
My address is NOT for sale, lease or rent.
Send me spam, lose your account. Get it? TINLC-1372
http://tehrasha.mamehost.com/******* B.A.S.T.A.R.D


------------

Or electronic/magnetic sensors embedded in the road.

Ed, NM2K

Hi Mark

I'll admit I have never actually noticed it but your experience sounds
plausible.

So me thinking in fundamental terms.

- The ground strap not working implies a charge and discharge cycle in
the wheel/axle.
- When you corner the tyre/road, tyre/wheel, wheel/axle conductivity (or
insulation properties) changes.
- When the road surface changes physical or conductive properties also
change.
- Wet weather mixes wth the road dirt and produces are better conductive
path and thus less of a voltage to discharge.

Does applying the brakes (better conductivity hub/disc to axle/car)
change or reduce the noise? (It will also distort the tyre shape in a
like mannner to cornering so this test may be invalidated. Try just
making the pads bind slightly with the drum/disc so it doesnt affect
tyre shape)

Does driving on a noisy stretch with a wheel on the lane marking paint
yield slightly less noise? (Wow, a new way to measure road speed!) If
this gets to be a positive test you can try one side or the other to see
if it is wheel dependent. (The kerb side tyres will of course have
slightly more surface on the road due to road camber,)

Hard to test but does the noise stop straight away on wet pavement or
does the water have to take some time to get well ingrained onto the
tread and side surfaces of the tyre?

The more tyre surface that is on the road (eg smooth pavement, cornering
G or wet pavement) the more likely the static charge will discharge at a
lower voltage (ie less noisy) Can you make the problem worse by adding
some more air to your tyres?

Road material conductivity to the underlying "ground" I dont think would
be that significant but I'll admit I have never measured it. I would
have thought that it is low enough resistance (including any rebar!) to
not be factored in. I am prepared to be shot down over this though!

Interesting/Intriguing situation! You can of course just try some of
that conductive powder that goes inside the tyre. Something like that
green roadside puncture repair stuff may also help and additionally give
you some protection for its priamry use!

Please get back to us with what you find.

Cheers Bob VK2YQA/W5 East Texas

(It is too dangerous for me to use AR in the car nowadays. I am so use
to veering the "wrong way" from driving for so long on the other side I
cant afford the risk! Sigh! - Yeah I also spell "tyre" the other way!)

Mark wrote:
WHEEL STATIC ONLY ON SOME PATCHES OF PAVEMENT? WHY?

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

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. It seems as if these certain locations have something
special about the pavement or the water content of the soil or
something. None of that seems likely to me though, I see nothing
changing in the pavement as I drive from an area of static to an area
of non-static. It is not related to stepping on the brake or gas or
shifting gears or going over bumps or any other aspect of the car that
I can tell other than it's speed down the road.
As an experiment, I attached a drag wire under the car. The wire
drags on the ground to discharge any static build up the car. This
made no difference. Another clue, we've had no rain here in a
while. The static all stops during wet weather. Also I am in the
Philadelphia area and the AM station is in the New York area so it is
on the weak side.
I've been a ham for over 30 years and I have a lot of experience with
EMI, but this one has me scratching my head. The wheel static
changes repeatably in different locations for no apparent reason.
It's got to be something to do with the pavement. Anybody have any
experience with this?

Mark


So get yourself a decent portable AM radio. Use it instead and if you
still hear the same static at the same locations, then you'll know
it's not the car.

My assumption is that it is the wiring in the car. Like a broken
ground wire near the wheel well or even corroded wires.

You can also buy filters which are generally capacitors that can be
installed before the radio.


I remember reading some time ago where some gal had this constant
noise not in her car radio, but her teeth! She tracked the source down
and found it to be a local radio station she was always passing.

Now me personally, I can never figure this one out.
Most of the time, when ever I go to bed, I'll hear a radio station.
It's just enough to be annoying. I can rarely tell what's being said
or played. I only hear it when I'm laying down on the bed, not sitting
up. So I figure it has to do with the springs.

Mark wrote:
"Wheel static only on some patches of pavement?"

Why any wheel static ever? Springs used to be installed in hubs to make
a sliding contact between the axle and the wheel. They must still be
available.

Graphite can be added to axle grease as is usual with speedometer cable
lubrication. Graphite is powdered carbon and conductive.

Best regards, Richard Harrison, KB5WZI

Richard wrote:
"She tracked the source down and found it to be a local fadio station
she was always passing."

We contracted a crew boat in S. Louisiana from Nolan Duet (Doo A`).

Nolan bought his wife a new car but she complained it made a clicking
sound as she turned corners. Nolan told her she would just have to take
the car back to the dealer.

Nolan said: "I wasn`t going to tell that woman that it was the buttons
on her dress that caused the noise!"

Best regards, Richard Harrison, KB5WZI

In article ,
Tehrasha Darkon wrote:

On Wed, 5 Nov 2008, Mark wrote:

I've been a ham for over 30 years and I have a lot of experience with
EMI, but this one has me scratching my head. The wheel static
changes repeatably in different locations for no apparent reason.
It's got to be something to do with the pavement. Anybody have any
experience with this?

Mark


My guess is different lengths/types/orientation of rebar in the roadbed.

for a while glassfault i spelled it wrong it was asfault
pavement that was made with recycled glass we did a test here in
nyc i belive the first to do such testing and it was very
conductive, caused a lot of problems with the testing gear so
they put metal scraps in the mix didn't help we paved
a 1/2 block test road initially and if you had the radio on
and drove over it you heard a clearly different background noise
ie higher


ultimately the fixed it forgot how i think they tumbled the
glass and added some chemical


dunno if this has anything to do w/your specific case but
anything from hitting a certain frequency vibration that causes
a lose wire to rattle to perhaps some crappy wires burred
under the st see any manhole covers around?? telco or
sewers? typically they all have some juice and often make a
bit of noise

Hello Mark,
I used to drive a semi trailer years back, and had the same problem. It
occurred only in fine hot weather, and the static build up used to wipe out
80m mobiling, plus the Am receiver on the broadcast band. It was what I call
"Tyre Static"

I noticed that in wet or damp weather it didn't occur, so I cured the
problem by simply introducing some graphite powder into the grease of the
outer wheel bearing on the front axle.

Later on I found that a molybdenum based greases did the same job, without
the mess of handling the graphite powder.

I also found that steel belted radials were the culprit, but the early rayon
biased tyres didn't suffer from the static build up problem at all. Main
problem was that the rayon biased tyres didn't have the speed or load
ratings the steel belted tyres have.

A big problem is that nowadays with the introduction of sealed wheel
bearings and front wheel drive vehicles makes it nigh impossible to
introduce graphite powder or to re-grease the wheel bearings.

By experimentation I found another cure, that was to put some graphite
powder inside of the tyre before mounting the tyre on the rim (wheel), that
reduces it as well. One can let the air out of the tyre and introduce
graphite powder through the valve stem and then re-inflate the tyre.

I found that the graphite powder inside of the tyre did not affect the at
all, we used to recap our truck tyres up to 3 times, only thing was the tyre
fitters hated dealing with the graphite inside of the tyre.

On another problem not really related to highway use is that when farm
tractors were fitted with UHF CB, ploughing in a paddock, static noise used
to build up to a point where communication were impossible even over a short
distance. The cure was to wipe the antenna down with a dry cloth.

Hope this helps
HarryH


"Mark" wrote in message
...
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. It seems as if these certain locations have something
special about the pavement or the water content of the soil or
something. None of that seems likely to me though, I see nothing
changing in the pavement as I drive from an area of static to an area
of non-static. It is not related to stepping on the brake or gas or
shifting gears or going over bumps or any other aspect of the car that
I can tell other than it's speed down the road.
As an experiment, I attached a drag wire under the car. The wire
drags on the ground to discharge any static build up the car. This
made no difference. Another clue, we've had no rain here in a
while. The static all stops during wet weather. Also I am in the
Philadelphia area and the AM station is in the New York area so it is
on the weak side.
I've been a ham for over 30 years and I have a lot of experience with
EMI, but this one has me scratching my head. The wheel static
changes repeatably in different locations for no apparent reason.
It's got to be something to do with the pavement. Anybody have any
experience with this?

Mark