Compass

I just bought what I thought was a good compass for the inside of my jeep. It
has two screws on the bottom that are supposed to be for calibration purposes
(compensating for any magnetic interference in the mounting area.) One for N/S,
the other for E/W.
The problem is that I can’t get the thing to read right in all directions.Just a
small tweak of a screw has a drastic effect on the other axis. If I get it to read
North, then get it to read east, the S and W are way the hell off. I tried to set it so
opposite directions are the same amount off the mark (ie.only remove half the
error) But if I get N,S OK then E,W is wrong, then if I tweak the E,W just a little, it
blows the N,S out again.
Does anyone have any experience with this sort of thing? ( Before I bring it
back, or throw it out.)

 

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I can not tell you about the compass itself. I can tell you that there are three norths. They are grid, magnetic, and true north. Grid is found on the map. The imaginary lines that "box in areas". Magnetic is found by compass to the mountains that have a huge amount of iron in them. (I think they are in the Urals). True north is where the actual pole is. There is a devatition factor for where ever you live in the world to convert magnetic to true. Or true to magnetic.

 

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Dump it!

Turbine,

There are now self-compensating electronic compasses available that are pretty rugged and weather proof ... and under a $100

 

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That's exactly what I did. Dump it. I didn't get one of those fancy ones though. Just one with stronger compensating magnets. The only place I could put it was on the windshield above the rear view mirror.The dash area would make them all go crazy,even with all power off.Even that spot on the window had a problem with the sunroof motor pulling on it.This one seems to comp. better and is behaving nicely.We'll see what happens when I put in my earth shakeing stereo.I'll use nice shielded wire on the floor.Something the auto"engineers" should think about (in the dash) I was never aware of ambient electromagnetic "static" untill now.

 

Compass shit

Glad you solved your problem, more or less, with a new one. Some of them have compensating magnets that are so weak it's almost impossible to correct for the EMF environment in some cars.