I'm about to instal a Garmin 128 GPS on Jissel. The most practical place for it is about 2" away from the compass. I can't find anything in the manual about a safe distance. Is this likely to be because it doesn't matter?
I've fitted a 126 just above the compass, Before doing this I tested if the compass was influenced by the GPS, I found no significant change whatsoever.
Sometimes it's the steel cases of the batteries that are magnetic. So just because the compass is not affected with this set doesn't mean that it will not be affected by any replacements.
There is no mention in my Garmin handbook of a safe distance, but I have held the Garmin 12XL right up against the compass without appreciable effect.
I have a 128 on my boat. It's about 3" away. Does not affect the compass. But before installing, wire it up and hold it near the compass - see if it has any effect!! I also have a fish finder close by as well and no effect from that either. I'd be very loathed to put a speaker near by /forums/images/graemlins/frown.gif, and a mobile phone does make the compass wander, but that's all.
quick tip. whether or not the garmin will affect the compass I cant comment, but the 12v power supply has this potential. you can reduce the risk considerably by twisting the supply wires like the old twisted flex., and dont seperate the + and - until some distance away from the compass.
(reason being a dc current flowing though a wire creates a magnetic field. if you have the two wires together this tends to cancel out fields - if twisted together this tends to cancel out fields even better).