Abu Dhabi Off-Road Club Forums

After setting up a BBQ point we went for a drive in the desert. Had some fun and returned to the BBQ way point. No issues, garmin worked perfectly.

I put the garmin away, went and had the BBQ, and after dark went to leave for the road. After getting the garmin back out and set to go to the road waypoint I had a problem:

The map and compass flipped 180 degree continuously. When I moved forward it settled down and pointed in the direction I was pointing. I set off and quickly realized it was exactly the wrong way.

Is this common? Is it a known issue? To fix do you just recalibrate the compass or is it more severe?

When back at the road the automotive profile worked perfectly. The off-road profile is using a garmin official map. Any advice very much welcome.

Thanks,
Lee.




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Hi Lee - as discussed this behaviour is normal with the Montana mounted in the cradle.

The Montana has a magnetic and GPS based compass. It automatically switches from the magnetic to the GPS once you start moving. The problem is that when you are stationary the magnetic compass is picking up the "North" from the magnet in the loudspeaker mounted in the cradle. This is one of the main reasons that I got the Garmin AMPS Mount instead, as it doesn't have the speaker mounted in the cradle.

If you recall on the lead and sweep with Adiga a while back, this is what I was referring to.

Try repeating the same behaviour and see what happens with the GPS dismounted.

Thanks Thom, I will try and hopefully fail to repeat.


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Dear zeebzog ,

As thom mentioned ,just keep it away of the loudspeakers magnetic field to have un affected output (same as the old compasses) ,and to get it magnetised free hold it in your hand and wave the device in an infinity shape (oo) around 6-7times.

I had the loudspeaker taken out of the cradle. The technician at AMIT did it
nicely and I keep the loudspeaker separately in case I want to install it again
in future.
The magnetic compass was behaving much better after that, however it can still
flip at times. The location of the cradle in the car is critical, e.g. near other
equipment like the car loudspeaker, the electronic instruments in the dashboard,
the windshield wiper motor etc. All these produce their own electrical or
magnetic field and disturb the earth's field. You can test that by changing
the cradle position along the dashboard, you will see the compass needle
changing direction.
Moving the car and let the Montana switch to GPS is the only ultimate solution,
but removing the loudspeaker or using a mount without loudspeaker helps.

Have a look at this thread too. And my post showing the compass readings with the magnet.

Dave

http://www.ad4x4.com/club/viewtopic.php ... 9&start=15

Thanks Dave, it looks like by me going slowly in the dark trying to find the track, and wondering why on earth it wasn't in front of me created the perfect environment to keep me going in the wrong direction...well they say the best way to learn is by experience..