Wierd Magnetic Fields?

OK... This isn't really a "problem" with the car, but it has me
baffled...

I have an 06 Civic Si. It is a great car, but it didn't come with a
compass, which I have always found invaluable, being that I do a lot of
on-site work all over Western NY and Northwestern PA.

So, I bought a little ball compass that can be stuck to the dash, suctioned
to the windshield or clipped to the visor. Simple solution.

The problem is that no matter which way I go, I am always pointed ENE
according to the compass, when it is anywhere inside the front section of
the car. I haven't checked it in the back, as I don't ever plan to drive
from there... ;-)

Before you ask, no there is nothing wrong with the compass. If I take it
out of the car and walk around, it works fine.

So, my question is simply if anyone knows what in the car could be causing
this. There must be something with a strong enough field that it is
pulling the compass, but I can't seem to narrow it down. I get the same
results with the compass in the passenger seat area or the drivers area, on
top of the dash or below, and even at the roofline.

I don't expect to be able to fix it. The only solution may be to buy the
stupid $200 option rearview mirror with a built-in digital compass, but I'd
still love to know what on earth is going on...

--
Joseph M. LaVigne

http://www.thelavignefamily.us/MyPipePages/ - 9/8/2006 4:11:03 AM
Tobacconist Brick and Mortar Database: http://bam.tobaccocellar.org/

"Laws that forbid the carrying of arms...disarm only those who are neither
inclined nor determined to commit crimes...Such laws make things worse for
the assaulted and better for the assailants; they serve rather to encourage
than to prevent homicides, for an unarmed man may be attacked with greater
confidence than an armed man."
-Thomas Jefferson, quoting Cesare Beccaria

 

When you move it around to various locations in front, does the direction
deflect slightly? If there were something inside the car that created a
magnetic field - under the dash or hood, etc. - it seems to me that the
lines of magnetic force would not all be lined up. In other words, in an
area that small, there should be a 'point' of origin somewhere. You could
even approximate the location by observing the compass deflection.

Unless the car is somehow acting as a coil, and the compass is 'inside' the
coil.

What about close to the car? Is there a clear line of working/not working as
you leave the car, or does the effect 'fade out?'

-- R Flowers

 

there's two things, the second being most likely:

1. the car's full of electrical gear - all of which generates
electromagnetic fields of some degree. you can figure out if that's the
cause by turning everything off and seeing if the needle moves.

2. the car's made of ferro-magnetic steel. that always has some degree
of "set" to it. theoretically, it's possible to neutralize this with
big electromagnetic coils running around the perimeter of the vehicle
[as used in shipping], but reality of course is that it's not practical.

 

No don't spend that kind of money for a compass. Just go to Sears and buy
the yellow digital one with the 2 rubber suction cups. I paid $25 bux and
it is excellent. You do a calibrate by driving in a circle and it
compensates for any magnetic variation in the vehicle. I love the thing.
RickOn Fri, 08 Sep 2006 04:17:39 -0400, Joe LaVigne

 

Does it make a difference if the car is on or off?
that could lead you in the direction of what is causing the pull.

Dave DeJonge




" I don't like guns"
- Dave DeJonge

 

My guess is that the car body is magnetized. I used to work in aviation and
would periodically see the problem in fabric covered planes that had steel
tubing frames. We would try to compensate the compass and we wouldn't even
get in the ballpark. (If the problem is electrical, you will see the compass
jump when you turn things on and off.)

It is theoretically possible to degauss the car body - it's the practical
part that gets in the way. The essense is to wrap the body with wire (the
way you are probably already thinking, from the side over the top and down
and around). The wire is connected to AC power - you'd want a few amps
flowing - that is slowly decreased. I've never done it because it was beyond
the authorization of our avionics/instrument shop. Whether you want a
compass enough to pursue that is up to you.

Mike

 

It's the radio speaker.

Al

 

You'd think, wouldn't you? ;-)

I do not find any serious movement from location to location. It always
shows ENE.

As soon as I get out of the car with it (even holding it out the window) it
acts normally. Strangest friggin thing I have ever seen...

--
Joseph M. LaVigne

http://www.thelavignefamily.us/MyPipePages/ - 9/9/2006 3:41:52 AM
Tobacconist Brick and Mortar Database: http://bam.tobaccocellar.org/

"Voting Democrat or Republican is like voting for which vehicle will carry
you to hell the slowest."
- Harry Browne, Former Libertarian Presidential Candidate

 

That certainly sounds most likely to me, too. The effect is the same with
the car on or off...

Thanks for the possibility...

--
Joseph M. LaVigne

http://www.thelavignefamily.us/MyPipePages/ - 9/9/2006 3:43:47 AM
Tobacconist Brick and Mortar Database: http://bam.tobaccocellar.org/

"If you can't sent money, send tobacco."

-George Washington to the Continental Congress, 1776

 

http://www.sears.com/sr/javasr/product.do?BV_UseBVCookie=Yes&vertical=AUTO&cat=Automotive+Accessories&subcat=Emergency+Kits+%26+Travel+Aids&pid=02823009000
http://tinyurl.com/ja56j

This one? It isn't yellow, but it looks like what you are describing. I
think I'll go get one tomorrow.

Thanks!

--
Joseph M. LaVigne

http://www.thelavignefamily.us/MyPipePages/ - 9/9/2006 3:45:47 AM
Tobacconist Brick and Mortar Database: http://bam.tobaccocellar.org/

"Man, the creature who knows he must die, who has dreams larger than his
destiny, who is forever working a confidence trick on himself, needs an
ally. Mine has been tobacco. "

-John Boynton Priestley

 

Nope...

--
Joseph M. LaVigne

http://www.thelavignefamily.us/MyPipePages/ - 9/9/2006 3:47:13 AM
Tobacconist Brick and Mortar Database: http://bam.tobaccocellar.org/

"I believe that pipe smoking contributes to a somewhat calm and objective
judgment in all human affairs"

-- Albert Einstein

 

I thought that, too, but considering that it doesn't change anywhere in the
car, including far away from any speakers, I think the magnetized body is
most likely...

--
Joseph M. LaVigne

http://www.thelavignefamily.us/MyPipePages/ - 9/9/2006 3:47:24 AM
Tobacconist Brick and Mortar Database: http://bam.tobaccocellar.org/

"You should never hate anyone because of his or her religion, skin color,
sexual preference or political affiliation. If you take the time to get to
know them as people, you will find there are any number of more valid
reasons to hate them"

-- Dennis Miller

 

When the outside of your car gets dusty, do you see the magnetic lines
in the way the dust settles? Just curious..
Nick

 

There you go! Get some fine metal filings and throw them on the car in
various places.

-- R Flowers

 

If the body of the car is magnetized, I don't think this would help.

 

I agree. Speakers have a very localized field and moving the compass even a
couple inches swings the compass a lot.

Mike

 

I am going to jump in here late. I do not think any of the answers
explain what the OP experienced. There are several issues with
compasses in cars, airplanes, boats, etc.

1. The compass needle is a magnet. It will point to the nearest peace
of ferromagnetic material. It will point to a magnet, but it will also
point to a nail, car pillar, anything made of iron or steel whether
magnetized or not.

2. The car is full of magnetic fields caused by wiring, speakers, etc.

Both of these issues are resolved by placing the magnet as close to
the outside world as possible, stuck to the windshield for example,
and then calibrating it.

But, the OP said the compass always pointed ENE (if I recall). I
assume this is regardless of the position of the car. This sounds like
a stuck compass needle. In other words, take it back and get a refund.


Elliot Richmond
Itinerant astronomy teacher

 

Not sure he said that (points ENE at all times) but I may be wrong.
What I do know he said is that it works just fine as soon as he removes
it from the car. There, I think, goes the stuck needle theory, right?

 

The OP said he tried it outside of the car and it worked fine.

 

I'll stick with the magnetized body. Steel vehicles are problematic for
compasses because they always introduce errors. Mostly the errors are not
big enough to cause trouble for a driver. Aircraft pilots have to know the
heading with precision but car drivers are happy with "kinda northeastish."

The problem is that when a car body is magnetized the compass is effectively
inside a magnet. That will make the compass point in one general
direction... in this case, ENE. How the car got that way and how to degauss
it, I surely don't know.

Mike