Gmu 11

This is getting interesting in deciding the location of the many parts to the G3X system. I am about to mount the GMU 11 in the wing and after reading the instructions on location I am not aware of any suitable location in the wing or fuselage. As I know this has been done with great success I also will have to deviate from Garmins wishes for NO magnetic, electrical carrying capabilities of interferences to be within 5 feet of the GMU, and don't even think about using a screw driver that might have a magnetic field. So what is a fellow to do?

As the folks at Steinair have told me, do the best you can and all will be fine. The one area of concern is Garmin does not want any ground from the strobes, landing lights grounded from their mounts to a carry through tube such as the wing spar. There should be a separate power/ground twisted wires. It seems this is to avoid the wing skins from setting up an interference field but since we have fabric is this really a concern? However, Areoled's wants the units to be grounded from the mounts. Perhaps I am not understanding this whole process but this is what I am reading into the install. Anyone who has been there and back again I would appreciate your input.

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Originally Posted by Flybyjim

This is getting interesting in deciding the location of the many parts to the G3X system. I am about to mount the GMU 11 in the wing and after reading the instructions on location I am not aware of any suitable location in the wing or fuselage. As I know this has been done with great success I also will have to deviate from Garmins wishes for NO magnetic, electrical carrying capabilities of interferences to be within 5 feet of the GMU, and don't even think about using a screw driver that might have a magnetic field. So what is a fellow to do?

As the folks at Steinair have told me, do the best you can and all will be fine. The one area of concern is Garmin does not want any ground from the strobes, landing lights grounded from their mounts to a carry through tube such as the wing spar. There should be a separate power/ground twisted wires. It seems this is to avoid the wing skins from setting up an interference field but since we have fabric is this really a concern? However, Areoled's wants the units to be grounded from the mounts. Perhaps I am not understanding this whole process but this is what I am reading into the install. Anyone who has been there and back again I would appreciate your input.

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I’m assuming the GMU is a magnetometer. The best spot is in the wing tip. I ran ground wires for my landing lights and strobes all the back to the firewall. The strobes are shielded wire. The only steel in the wing tip it screws, rivets, and nut plates. Less than everywhere else. I also put mine about a bay in so that it’s decently far from the tip hardware

Hey Jim, I understand it just as you have described. This subject has been discussed before and as I remember it, the consensus was just as Josh described. My grounds will run to the firewall as well.
Eddie

Thanks,

I talked to Garmin today and they realize most planes will not meet their ultimate requirements. They agree the wing outer bay is the best place to go with this and as long as the power/ground are twisted and go to a ground not near the magnetometer all should be fine. I started tonight to make a tray for this, will install tomorrow. Photos to follow.

Jim

Jim,

I assume you've seen the position of the GMU-11 on my "...Shed" thread. I was concerned about interference from the Microsun Landing/Wig-Wag and Nav/Strobe lights and ended up installing the complete Garmin system in order to run the interference tests before covering the wing.

Shielded 4-conductor cable was used for the MicroSuns and the +/-/CAN Hi/CAN Lo wiring to the magnetometer. The ground wires from each device are only connected to the common ground bus behind the panel. The shielding is currently not connected to ground at either end. In fact, with the 4-conductor plugs at the wing root, the shielding isn't continuous along the entire wiring path. This approach is based on my very limited understand of the electrical noise generated by the strobes and my understanding is on the level of the flat earthers or those insisting the moon is made of cheese.

The Garmin magnetometer interference tests "listens" to the GMU-11 while you exercise all of the electrical equipment in the wing. I flipped lights on and off in various combinations multiple times and the unit always passed the test. From memory, I believe the Wig-Wag generated the highest noise but placing the GMU-11 back towards the rear spar nicely reduced the effect to around 11% or so. Please go to the trouble of running your own tests for peace of mind before covering.

I am really glad to hear there are others out there that don't believe in cheese in space. Good one.
I have installed the Gmu11 just one false rib toward the root as you have yours so I am hopeful I will have the same results. I am working on the plane all day tomorrow, I may give you a call about the first power on of the G3X.

Thanks