Re: AV30

Jay Scheevel

I suspect it is a design and/or magnetometer-quality issue. They have decided to fit everything in a tight space, and with everything else that is going on in there electrically, it must be an impossible balancing act.


I have a Dynon Skyview with a separate ADHRS unit (which contains the magnetometer). This is located remote from the EFIS, but not very far away and is still behind the panel and I have not had any trouble with stable magnetic compass using this installation. Even so, Dynon offers a separate magnetometer for problematic installations. Dynon’s setup also allows for installing a second ADHRS unit for redundancy in a stack, although I have not done this.


I think that uAvionix wanted to make a splash by doing everything in a very small self-contained unit and they have found out by now that stray EM energy is impossible to block within a small distance of a pile of electronics, screens and power supplies.  They should have anticipated this in the design phase. Sounds like a marketing-department imposed constraint.


You may be able to mitigate the “precession” by identifying any component that changes its EM emission profile over time. The only one of these I can think of is the flat screen, as it may build up static electricity on it’s surface over time. Maybe finding a way to discharge this, like a small bare ground wire wrapped around the perimeter of the screen? Just thinking out loud here.





From: <> On Behalf Of hgflier via
Sent: Friday, December 2, 2022 10:26 AM
Subject: Re: [Q-List] AV30



Isn't the precession problem inherent in any gyro-based compass/DG? 
... though I suspect some gyros have less precession than others. 
Isn't installing an external magnetometer the right solution? 
Geoff N82GK 


On Saturday, November 26, 2022 at 08:28:09 AM PST, Jim Patillo <logistics_engineering@...> wrote:



Good morning all,

I recently installed two Uavonix AV30’s in my plane and removed all the vacuum stuff. That all worked great and I really like not having vacuum. Each unit is a full blown AHARS.   Having said that, the DG unit cannot hold a heading worth a crap and precesses within 10-15 minutes to where it has to be reset with the compass. I’ve tried calibrating it but no joy for better performance. I can buy an external magnometer to solve this but would rather not. My question is, has anyone else seen this problem and how did you solve it. 

BTW, I hope to pass 2000 hours on my plane this year. It’s been a blast. Keep building only if it’s a little every day. There is actually an end believe it or not, and you will be greatly rewarded! 

N46JP - Q200

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