MAG-236 harness question

[Malndi]

I’m installing a magnetometer in the empennage of an RV and planning to fabricate a harness using a pair of 4-core wires. Can pin 5 be omitted from the SV harness in this situation?

 

[Rhino]

Not sure. Out of curiosity, why not just use the correct cable?

 

[Malndi]

Mainly because I’m on the other side of the planet wanting to get it done without the weeks-long wait for stuff to arrive.

I think I’ll just give it a try. Worst outcome is it doesn’t work and I’ll need to order the correct cable.

 

[Rhino]

Fair enough. You could ask Dynon directly.

 

[Malndi]

For future reference, the magnetometer works fine without pin 5 included in the harness. After ground and flight calibration I have a calibration quality of 129.

 

[gordonwhite96]

Any chance you could share a picture of your mounting location? Thanks!

 

[Malndi]

It’s under the empennage fairing, attached with brass screws sourced from Spruce. I think placing it over the lightening hole has an advantage in the event that water gets in there. This photo was before the harness was secured.

 

[gordonwhite96]

Thanks. I just mounted mine there, did the ground calibration and in-flight calibration, but I'm still off by 15-20 degrees from GPS. The installer originally mounted it under the pilots seat (no idea why). Do any of you think it's possible that the mag is damaged or otherwise magnetized in an unusable fashion after having been mounted in a really bad spot? I can get screen shots of the calibration page.

 

[maartenversteeg]

Just mounting it in a bad spot shouldn't affect the mag permanently

 

[Rhino]

Just mounting it in a bad spot shouldn't affect the mag permanently

Nope. It's just temporary until you move it to a better spot.

 

[gordonwhite96]

Mine's mounted in the same spot with non-magnetic screws. However, the two bolts behind that holding the vertical spar to the horizontal spar are definitely magnetic. I can't seem to get it calibrated to be close to useful. I'm hoping someone might have a suggestion before I go to wing tip mounting.

 

[Malndi]

You mentioned that your heading is off the GPS by 15-20 degrees. But before that, how is the ground calibration? Is the heading indication accurate when the stationary plane is pointed N/E/S/W with the engine running and the canopy closed?

 

[gordonwhite96]

No. I need to take a picture of the ground calibration screen, but I'm pretty sure that it is incorrect. I went to another airport last week and did the ground calibration on a compass rose. I'll try to get a screenshot tomorrow.

 

[Malndi]

I don’t think the spar bolts would be an issue. Do you have a strobe light or any other electric device in the tail that could be generating a magnetic field?

Suggest methodically working through section 20 of the SkyView System Installation Guide – Revision AR.

 

[gordonwhite96]

The pitch trim wires are nearby (bottom right of the picture. But I wasn't actively changing the trim while calibrating. For this install, I tried to get in the center of the plane, but having read the install guide again and looking at your picture, I can move it over to the side away from the trim motor connection. Thanks for the reply! I'll start reading the install guide again.

View attachment 50mr.jpg

 

[Malndi]

Looking at your photo, these statements from the install manual suggests that moving the connector further away could improve things:

To minimize any potential magnetic interference from the connector, it is recommended to not locate the connector near the SV-MAG-236.

To minimize the possibility of magnetic interference from the connector assembly, the SVMAG-236 uses an 18-inch integral cable – the connector is remoted from the magnetometer sensor.

 

[gordonwhite96]

Update...I *think I'm good. Going to calibrate on the ground at another airport that has a compass rose. Got a flat tire landing at my home airport today, so might be a couple more days before I'm confident this issue is solved. Thanks for the guidance.