Thread: Car Compasses. Do they work?

The accuracy of a compass Will be affected by the steel in your county But I imagine that if you got a top quality compass and also got it calibrated it Could be used for navigation, However this would be a VERY expensive exercise.
Good off road/road combination GPS units are easily sourced, reasonably priced and are easy to install So personally I would be going down that road for your navigational needs.

I run a Hema HX7 in my D2a and I also carry paper maps and a hand held compass when I go bush, You need to be several meters from the vehicle to use the compass for it to work with any accuracy So it is a PITA to use.

Originally Posted by alittlebitconcerned

Hello wise forum.

I’d love to get a (non electric) compass for my county because if I were to shut my eyes, do a pirouette, i’d get lost.

There’s a bunch online that are the ball type floating in liquid. Some say they have compensators built in to allow for anomalies, but there’s not much info on what those anomalies might be.

My concern is that my county will act as a Faraday Cage and foul the reading of any compass placed inside.

what say you wise forum?

I have one in my D4. It can vary anything up to 20 degrees from magnetic north (depending on how much crap is in the dash area - eg mobile phone in holder connected to GAP Tool, triple CIG plug extension, TomTom GPS, Safety Dave rear camera screen).
Had instructions for setting and worked better in the D2a where it had a clearer location.

Hi

Just to prove that we are indeed wise :-)

Originally Posted by alittlebitconcerned

Hello wise forum.
My concern is that my county will act as a Faraday Cage and foul the reading of any compass placed inside.

A Faraday cage stops electromagnetic fields which have time varying electric and magnetic components. The electric component of a radiating field induces currents in the conducting mesh or surface of the cage which cancels the effect of the radiating field within the enclose. So it does not work for slowly varying fields or static fields such as magnetic fields.

But your right in that the County is a big lump of steel and will adversely affect a compass. As others have suggested go for a GPS.

Mike

These "ball type" compasses are feasible for use in Landrovers because of the largely alloy body, and the County is better because of the non-magnetic windscreen frame. I had one in my Series 1 and 2 in the 1960s, and it worked moderately well, even with the steel windscreen frame.

It should be mounted as far as possible from any substantial steelwork, a suction cup below the mirror perhaps.

Some of them have permanent magnet adjusters which can be adjusted to compensate for permanent magnetism in the vehicle. None have soft iron correctors or Flinders bars that are needed to fully correct for soft iron magnetic effects of the vehicle, which, fortunately, are relatively small on a County.

With permanent magnet correctors it should be possible to get within ten degrees accuracy, but don't expect much better.

When I was a kid my family had a Jeep Wagoneer with a big, beautiful compass in a binnacle on top of the (steel) dash.
It looked great, factory fitment I believe, too.

It didn't work.

go buy a really cheap phone and download a compass app onto it...it wont be affected by your vehicle.

or if the suns out you don't need a compass , just use a stick and draw a clock on the ground. the bigger you draw it the more accurate it will be.

if it's night time use the stars.

there you go, two easy things to learn that might just save your life.

Hi

Originally Posted by ramblingboy42

go buy a really cheap phone and download a compass app onto it...it wont be affected by your vehicle.

And how do they work? If it's not using GPS i.e. it's using the devices inbuilt magnetometer chip, then it's still using the Earths mag field and will be just as wrong as a Boy Scout's compass.

Mike

Originally Posted by ramblingboy42

go buy a really cheap phone and download a compass app onto it...it wont be affected by your vehicle.

or if the suns out you don't need a compass , just use a stick and draw a clock on the ground. the bigger you draw it the more accurate it will be.

if it's night time use the stars.

there you go, two easy things to learn that might just save your life.

Don't even need to draw circles, if you know the approximate time. Using your analog watch ( or if you don't have one, just imagine the face). Point the 12 position at the sun, half way between that and the hour hand, is North.
Good enough to get you out of (or maybe into) trouble