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Remote AHARS/Magnetometer placement

After installing my Dynon remote magnetometer and AFS AHARS on a shelf just behind the baggage compartment bulkhead, I realized my seat harness cables, running from one of the back bulkheads, would be too close to both of these instruments. Can anyone shed some light on where to place these instruments to avoid the harness cables?
Sierra Delta
 
On the 7A the shoulder harness cables anchor to the longerons running along the sides of the fuselage. Is it different in the 9? I mounted mine on a shelf I fabricated back there behind the baggage bulkhead, hanging down from the stringer going along the top of the fuselage. No problems in 305hrs. The seat belt anchors don't move and I think they may be only marginally magnetic (a specific alloy of stainless?). I can't imaging there would be a problem with the AHRS unless the magnetometer is integral and even then, my magnetometer is back there and there's no problem. You could take a small compass and see if it reads differently in that location than in free air...
 
Test the mounting

After installing my Dynon remote magnetometer and AFS AHARS on a shelf just behind the baggage compartment bulkhead, I realized my seat harness cables, running from one of the back bulkheads, would be too close to both of these instruments. Can anyone shed some light on where to place these instruments to avoid the harness cables?
Sierra Delta

Try reading your AHARS with the shoulder-harness metal-cable hanging down, then pull the harness so that it is in the same relative position as when flying. Then read the AHARS again, to see if the readings differ.

Another way to check the magnetometer is when flying in an area with stable winds, turn the airplane into the wind direction shown on the AHARS, to see if the readings make sense.
 
I located my Dynon ADAHARS in the inboard left wing access port just aft so I could operate in there. I made a bracket screwed to the wing rib flanges to level it. It is working great for 150 hours.
 
I put mine on a pair of angles behind the baggage area, just forward of the 707 bulkhead.

Actual, measured deflection from "No cable" to "Seatbelt cable draped over ADAHRS" was 3* compass deflection. With the cable in its' normal (you're wearing the harness) position, no measured deflection at all.

Close enough for RV work!

Aligning the ADAHRS and testing for interference.
 
Remote AHARS/magnetometer location

Thank to everyone for the advice. I'll try the compass idea to see if I get any interference.
Sierra Delta
 
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