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GMU-22 interference

Qui

Member
I have a GMU-22 magnetometer installed in my left wing. Since I used vans wiring harness, I purchased Whelen's LED strobe/nav lights so that I wouldn't have to run an extra shielded wire. Anyone else have the same combo with the G3X system? The magnetometer test fails with the use of the strobes. Wondering if anyone else ran into this issue
 
I have a GMU-22 magnetometer installed in my left wing. Since I used vans wiring harness, I purchased Whelen's LED strobe/nav lights so that I wouldn't have to run an extra shielded wire. Anyone else have the same combo with the G3X system? The magnetometer test fails with the use of the strobes. Wondering if anyone else ran into this issue

I am using the G3X Touch (GDU460 & 465) with a GMU 22 and Whelen's Orion 500 in the tail, and Orion 650E in each wingtip. The GMU 22 is mounted on the aft fuselage deck in my RV-7 well away (> 12") from any wiring.

Just for grins/giggles -- does it also fail with the nav light on? Try disconnecting the strobe/nav unit in that wing and see if it passes.
 
Works fine with the nav lights but fails badly with the strobes. I may have to relocate it behind the baggage area
 
Are you able to relocate the GMU 22 further from the strobe wiring? It doesn't take much.
 
I’ll second the comment about it doesn’t take much. I was able to go from a fail to 5 years of no faults by moving the wires a few inches further away.

In my case was a mid wing GMU installation, not sure what your layout is, but if you have wires that are a bit too close it’s worth a shot.

Derek
 
The lights were grounded on a rib but I have temporarily changed that direct the
main ground bus bar (had no effect). I have now run a temporary shielded wire (strobe & sync) and it cut half the error out, so making some progress. I place the wire on top of the wing and tape it to possible wiring routes but every position still fails. If I place the wire 1 inch behind the wing, it passes with flying colors.
 
. If I place the wire 1 inch behind the wing, it passes with flying colors.

Just need a few adel clamps bolted onto the trailing edges and good to go.;)

Where is the 22 mounted, on the horizontal plane? Fore, aft or center? Might consider moving it aft to the point that the steel tube in the aileron or hinge parts start to cause interference; If it does. And then run the wire through the forward lightening hole with tape holding the wire to the inside of the leading edge. Need to ask vans, but suspect that an 1/8" hole is the spar is no issue. It already has hundreds of holes in it for rivets and bolts. If it is an issue and if you're creative, you should be able to fish the wire between the spar and fuel tank; no need to drill spar.

Might be easier to just move it somewhere else though.

Larry
 
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Problem solved. 2 solutions 1- I used shielded wire for the strobe power and ground then test routed it behind the rear spar. Vans said no problem drilling a pass through hole if I decided to go that route. The magnetometer test barely passed at 97% (100% is a fail).
2- I then ordered tinned copper braid from ACS and then inserted the shielded wire inside and what a difference! I now am at 14% with the wire running inside the wing, no problem whatsoever
 
Problem solved. 2 solutions 1- I used shielded wire for the strobe power and ground then test routed it behind the rear spar. Vans said no problem drilling a pass through hole if I decided to go that route. The magnetometer test barely passed at 97% (100% is a fail).
2- I then ordered tinned copper braid from ACS and then inserted the shielded wire inside and what a difference! I now am at 14% with the wire running inside the wing, no problem whatsoever

Have you flown it yet? Are you building a 14 or 14A. My MU22 had no issues with wire causing interference in the magnetometer test on the ground but when flying I get AHRS magnetic anomaly errors occasionally. After talking to a variety of people the 14 seams to work in the location vans has but I am thinking the landing gear on the 14A is an issue. Anyone have it working in Vans suggested location on a 14A.
 
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