"David Koehler" wrote

Oh FYI the magnetometer is for my plane, I got divorced and quit smoking,
wow, have enough money to buy a kit plane....

I like all of the "good natured ribbing," but I guess in a way, what we are
saying is that weasel words are good enough for what I am guessing you are
asking. If you are asking about where to put a compass, you put it as far
away as you think can, from the ferrous metals and currents, (especially
large ones) and where you still can see it to be easily read. The rest can
be tuned out using the compensators built into the compass.

If that is not what you are asking, "nevermind." g

After all, the best place to put it, would be on a boom out away from the
plane by several feet, or trailing the plane on a long string, but it would
not be of any use to us, either of those places, or any of a number of other
places.

Where do you usually see a compass? If it is a whiskey compass, it is
usually on the glareshield, or at the top of the windshield. Usually, it is
in the middle, so you can see it from both sides of the cockpit, but also so
it is somewhat (more weasel words) in the middle (symmetrically) of the
interfering metals and currents.

If it is a type that has a remote sensor package, then you get lots more
options.

Generally, you put it far away from the engine as possible in an aluminum
plane, or away from metal frame members in a tube and fabric plane. I'm
sure your literature on the specific instrument has some pretty good
guidelines; follow them the best you can, and it will be good enough.

And of course, this advice is worth exactly what you paid for it. ;-)
--
Jim in NC