Need to De-Gauss Car

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davidmc36

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So I get a compass to install in my car.

Pin it to the dash with a couple of brass screws and go driving around.

Tried it out in the yard ahead of time and it seemed like a decent instrument.

As I cruise around with it mounted on the dash, it just keeps pointing North-ish.

So I fire up my GPS with electronic compass and same deal, anywhere I place it in the car it points North-ish.

I get out of the car (parked pointing South) with the compasses and open the back hatch and walk from a few feet behind and as soon as the compasses break the plane of the rear hatch opening, they spin around to North.

How do you De-Gauss an entire car!:lol::confused:
 

clanusb

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true hand held compasses always point to magnetic north...yes.....

i think he wants it to display the direction he is currently traveling...like most car trip computers do now a days where it displays the temperature and direction...like 74 NE
 

davidmc36

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true hand held compasses always point to magnetic north...yes.....

i think he wants it to display the direction he is currently traveling...like most car trip computers do now a days where it displays the temperature and direction...like 74 NE
Exactly, the rotor or needle should always point in the same direction and you or your car should rotate around it so the current heading would be shown, but in this case it stays pointing at the "North Pole" of the car, not the earth, so the "displayed" heading never changes.
 

kb2vxa

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This is a common problem when you put a compass in a cage of steel; the internal magnet seeks out the closest magnetic object being shielded from the weak magnetic field around it, in this case it's simply aligning itself with the metal car body. Put it to the test, take it outside and walk around the car observing the errors when you're close enough to it. They work just fine in a wooden or fiberglass boat which is the purpose of having one in the first place, when driving a car it is assumed you have some sense of direction from your surroundings.

BTW I was going to say this right off the bat but waited for the usual funny stuff, I can't wait to see where this leads. (;->)
 

davidmc36

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This is a common problem when you put a compass in a cage of steel; the internal magnet seeks out the closest magnetic object being shielded from the weak magnetic field around it, in this case it's simply aligning itself with the metal car body. Put it to the test, take it outside and walk around the car observing the errors when you're close enough to it. They work just fine in a wooden or fiberglass boat which is the purpose of having one in the first place, when driving a car it is assumed you have some sense of direction from your surroundings.

BTW I was going to say this right off the bat but waited for the usual funny stuff, I can't wait to see where this leads. (;->)
I did do some testing and found it starts to wander when you get within about three feet or so and spins right around when it enters the car. I expected some error but not to be absolutely useless. Guess I will have to put in an HSI an a couple of flux valves. Tee Hee Hee

I am glad I tested with a less expensive unit before I bought the $100 one that I really wanted.
 

kb2vxa

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"Guess I will have to put in an HSI an a couple of flux valves."
You need them to drain the flux capacitors or every time you hit 88mph you'll never know when you're going.
 

kb2vxa

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"It's time to start backing in to your driveway."

Not one bit funny David, not in New Jersey at least. Paraphrasing our statute; one must exit a driveway, alley or parking lot in a forward direction, stop before the sidewalk, yield to all pedestrian and vehicular traffic, then proceed at a speed not to exceed 4mph.
Reversing out of a driveway puts traffic in your blind spots putting you at risk of getting T boned or running somebody over.

Here's another "everyone" seems to ignore, it's illegal to enter or exit a vehicle on the street side. If somebody takes your door off and/or makes a bloody mess of you, tough noogies. If you survive not only will your insurance not cover you but you'll get handed a wolf ticket as well.

OK, lets get to the giggle factory. Backed in the driveway those cellular horn tweeters mounted on your trunk lid won't be so recognizable, thus saving you the embarrassment of being called a weirdo by your neighbors, a public nuisance every time a boom car goes by or having them stolen by some audiophool. On the other hand you could install the Mad Max anti-theft device, just sit back and watch the fun begin.

Uh, did somebody mention a compass?
 

KE5MC

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Swing and compensate

Your compass might/should have an adjustment on the bottom. One is north/south the other is east/west (compensators).

Go to a large open parking lot and use a hand held compass away from the car to identify North. "Swing" the compass in the car by positioning the car with the compass in its final installation location. At each compass point adjust the proper compensator to get the compass to read the correct direction. Do this several times and the adjustments will get smaller and smaller. It will never be perfect, but it will be better than you have now.



So I get a compass to install in my car.

Pin it to the dash with a couple of brass screws and go driving around.

Tried it out in the yard ahead of time and it seemed like a decent instrument.

As I cruise around with it mounted on the dash, it just keeps pointing North-ish.

So I fire up my GPS with electronic compass and same deal, anywhere I place it in the car it points North-ish.

I get out of the car (parked pointing South) with the compasses and open the back hatch and walk from a few feet behind and as soon as the compasses break the plane of the rear hatch opening, they spin around to North.

How do you De-Gauss an entire car!:lol::confused:
 

jbantennaman

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Working with powder metal machinery for several years, we did degauss parts of a powder metal presses.

The problem with trying to degauss a entire car is that there is moving parts on the car such as the wheel bearings and when the wheels spins, the wheel bearings will cause the vehicle to become magnetic.

On a ship, you run the entire ship through a electro coil which degaussed the entire ship but the ship travels through water and has a constant contact with ground through the water.

A automobile runs on rubber tires I would hope and the static electricity that builds up in the chassis from the insulating property's of the tires on the road and the vehicle traveling through snow and water would cause build up and discharge of the static energy.

You could try to drag a chain under the vehicle, or you could use some of those rubberized ground flaps that people used years ago to get rid of the static but even that would not help when you have a simple magnet trying to point to magnetic north when 1/5 of the vehicle is comprised of steel.
 

davidmc36

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Your compass might/should have an adjustment on the bottom. One is north/south the other is east/west (compensators).

Go to a large open parking lot and use a hand held compass away from the car to identify North. "Swing" the compass in the car by positioning the car with the compass in its final installation location. At each compass point adjust the proper compensator to get the compass to read the correct direction. Do this several times and the adjustments will get smaller and smaller. It will never be perfect, but it will be better than you have now.
The built in compensators would not even come close to straightening it out. They only do about +/- 30deg. Doesn't help much when it points within 15deg of North no matter which way the car is pointing.
 

davidmc36

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"It's time to start backing in to your driveway."

Not one bit funny David, not in New Jersey at least. Paraphrasing our statute; one must exit a driveway, alley or parking lot in a forward direction, stop before the sidewalk, yield to all pedestrian and vehicular traffic, then proceed at a speed not to exceed 4mph.
Reversing out of a driveway puts traffic in your blind spots putting you at risk of getting T boned or running somebody over.?
No kidding. I expect that is pretty much a unviersal law. I had to do it on my driver's test. They are so serious about it in Nova Scotia that a workmate of mine was backing out one night and got walloped by a drunk driver with no lights on and still got nicked for the backing out fine.:eek:

The backing in idea sounded like it would help my by correcting a backwards compass, or just help me know where I was going if I drove out forwards (then I could see where I was going and not need a compass), and that was funny.:D
 

davidmc36

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Compass seems to work fairly well in the wife's car. Have not spent any time swinging it but it probably will adjust half decent.
 
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