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MG MGF Technical - Fitting a magnetic compass
|I recently bought a small magnetic compass for my MGF. You know the type, small stick on windscreen/dash device. Only problem is it only indicates north west whichever way I point the car. Obviously there is some magnetic interference but it seems to affect the whole of the windscreen dash area. The compass works perfectly when away from the car. Has anyone else had this problem and how did they get round it?|
|Bruce, these stuff is only good for the guy who sells it ;)|
I understand you but the compass was cheap and works perfectly in other cars. I guess it may be to do with the steel roll bar in the windscreen surround. If, while I am sitting in the car, I hold the compass in my hand at least 40cm away from any metal it is still affected. Oh well, I suppose I could put it in my wife's car!
OK, now serious :)
I suppose you are right. May be in non-convertible cars the magnetic distortion fields are more non-directed. At the MGF the metal parts look more concentrated .. you know what I think ?
So may be the poor compass can 'see' the screen frame only as strong directed magnetic field ?
|I suppose I could mount it on a 3 metre wooden pole sicking out in front of the car but then I would need binnoculars to read it! LOL|
|These devices usually have a small adjusting screw to eliminate the effect of the surrounding metalwork, if your's doesn't have one perhaps it was too cheep!!|
|the expensive solution is to buy a GPS unit....|
|The cheapest solution is to look at where the sun is. No use in the UK, of course.|
You are quite right, this compass does not have any compensation devices fitted. I will try to find one which does. I wasn't expecting it to be accurate, just give me an indication!
Tried fitting one of these in my car as well, and suprise, suprise, the only direction the car was going in was .......NW. Shame, a nice little black and crome jobbie, just matched the gear stick and surround.
Saw an expensive electronic jobbie in Halfords, but have lost all faith in accuracy and hey it's got to look right!
|>No use in the UK, of course|
Yes, of course, but you are not alone.
Wonder in any way, why a compass is required in England.
.. LOL.. you can go in each direction for a 'few' miles and reach a cost.
PS please don't scalp me for this bad joke ;)
|Any direction I go will cause me cost Dieter! Your English can be funny at times. I think you mean COAST.|
I have now discovered that my steering wheel (standard) is very magnetic!
|>Your English can be funny at times. I think you mean COAST.|
ROFL ... of course the coast.
Funny at times ? *g* Always, Bruce, always :)
|Checked again this morning using the compass. The steering wheel is polarized north south across the horizontal diameter of the wheel. Compass points one way on one side and 180 degrees opposite on the other, even when held a couple of inches away from the wheel. Very curious. I wonder if all MGF steering wheels are the same and why? Perhaps I could demagnetise the wheel?|
The solution is simply to turn the steering wheel until the compass points to true north.
|>Perhaps I could demagnetise the wheel?|
A very good idea ;)
Just park the car in a way that the north-south polarization directs from east to west (west to east may work also).
Than use a BIG HAMMER and beat on the steering wheel.
I remember first school experiments in Physics due magnetism and we demagnetised a polarized nail in the same way.
BTW don't beat to often, cause the steering wheel may get polarized to this opposit way than.
PS. hard stuff, is it ? ;) May be the complete car can get de-polarised in the same way. Who tries ... LOL...
|>>>>Very curious. I wonder if all MGF steering wheels are the same and why?|
Hang on, don't some airbags work on the priciple of a big steel weight held in place by a magnet, which only flies forward after a big impact to complete a circuit? Does the F bag have one of these? If so, then demagnetising it may have explosive results!
I did like Dieter's way to fit a compass - beat the steering wheel repeatedly. Entirely sensible. :)
|I think the sensor for the airbag system is fitted behind the centre console.|
|My father had the same problem 25 years ago in a Cortina. I suspect that whatever the make and age, a car is a maze of electromagnetic fields.|
|you could always have the car de-gaussed.|
Used to do it to ships in the war to stop them setting off mines.
But why on earth do you need a compass- Cross country?
|A compass is always useful if you are lost. At least I can head off in the right direction. My good lady (God bless her) is not the best of map readers and many an argument has ensued at or just after major road junctions! Anyway as an ex pilot I feel comfortable with a compass to look at.|
|I agree ....you can never get lost with a compass and a map. Shame the compass thing doesn't work.|
|Go the whole hog!! Get a Garmin Street Pilot Colourmap GPS unit - not only does it tell you where you are, what streets are coming up it also has a built in compass which as it gets its bearings from triangulation on as many as ten satellites is not effected by the cars metal bits. It also has a trip device that gives a whole lot of interesting information and BTW you can programme it to give you directions PLUS it is not a permanent fixture so can be moved from car to car or in my case car to motorbike.|
OR wait until the end of the year when they are bringing out a newer version with instant 'turn by turn' route finding.
|At what price Ted? I would guess several hundred!|
|Basic GPS from Maplin.com £130|
|You are correct Bruce and the the site pointed out by Dot - GPS Warehouse are very good - I have used them a couple of times.|
I have to point out that the Garmin unit is full SatNav not just a GPS unit and one of the things that attracted me is the fact that is does not require a CD unit to be attached to it - the CD Maps are downloaded onto removable memory chips - not much bigger than a postage stamp and the Garmin unit will also work from it own internal batteries (even if they only last a couple of hours)so it can become a truly mobile unit although perhaps a little bit too big for hiking!
This thread was discussed between 19/08/2001 and 28/08/2001
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