Dual magnetometer interference.

[Captain Avgas]

I have one magnetometer for my AFS 5600 and another for my Dynon D6.

The AFS installation manual recommends a minimum distance of 10" between dual magnetometers but for logistical reasons I would like to locate them on the one support tray with only 4" between them.

Some years ago Paul Dye claimed he co-located two magnetometers directly on top of each with no adverse effects.

Have any other builders had positive or negative experiences with positioning two magnetometers in close proximity (within 4" of each other).

[Pat Hatch]

Bob, I mounted two Dynon magnetometers next to each other on the rear empennage deck between the horizontal stabs in an RV-7. No adverse effects at all. Here's a pix:

[Ironflight]

FYI - the stacked magnetmeters have been working fine in Mikey for the past five years - no disagreement, no interference....they just - work! (Or so I claim.... )

[BobTurner]

A simple test: get a magnetic compass. Put it on a wooden bench. Now move the magnetometer, including the mounting hardware, all around the compass. If its indication never changes, you're good to go. If it does change, back off until it doesn't. That will give you the minimum separation needed.

[Captain Avgas]

Following up on Bob Turner's advice I tested both my Dynon and AFS magnetometers using a large fixed whiskey compass in an Auster. I thought others might be interested in my results.

The sole critical object on both magnetometers was the nine pin Dsub socket (presumably has some ferrous content).

With the Dsub socket directly next to the compass (virtually touching) I registered a compass swing of up to 10 degrees. At a distance of 3/8" the effect had completely disappeared. I therefore concluded that a distance of 1" from the Dsub to any part of the adjacent magnetometer would be safe. I have 4" so that should be more than adequate.

Thanks also to Pat Hatch and Paul Dye for their assistance. The internet is a wonderful thing but in the end it's the willingness of other builders to share their knowledge and experience that makes VanAirforce such a really powerful tool.