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Old 03-29-2017, 03:58 PM
Brent 801's Avatar
Brent 801 Brent 801 is offline
 
Join Date: May 2012
Location: Conroe, TX
Posts: 28
Default Pitot Tube wiring past Magnetometer

I'm preparing to run the wires from my Garmin GAP 26 heated pitot inboard to the fuse. Is there any concern about running the pitot heat wiring close to the Garmin Magnetometer which is installed in the left wing where a Dynon ADAHRS would by located if using Dynon?
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Old 03-29-2017, 05:17 PM
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Pitot heaters are heavy current users, this means serious potential for magnetic interference. Best practice would be to run a twisted pair (pwr/grd) from the tube all the way to the switch and ground block and keep the wiring as far as practical away from the magnetometer, then keep your fingers crossed.
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Last edited by Walt : 03-29-2017 at 05:19 PM.
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Old 03-29-2017, 05:57 PM
DerekS DerekS is offline
 
Join Date: Apr 2013
Location: Ontario, Canada
Posts: 31
Default My Experience

I have mine quite close to the pitot, and am using Dynon's temperature regulating probe which I imagine is noisier than just an on/off spike since it has to regulate.

First time I tested it was close enough to fail the self-test. In my case I was able to reroute the wires so that they were 6 inches further away, at which point I no longer saw any impact when I turned it on or off during the self test.

Distance really does matter a lot, and 3 or 4 inches is too close.

(In my case not a twisted pair install)


Derek
YMMV
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Old 03-29-2017, 06:50 PM
KeithB KeithB is offline
 
Join Date: Mar 2014
Location: Granbury, TX
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Yes, pitot heat power will interfere with the Garmin magnetometer mounted on the ADAHRS shelf. I ran a power wire in the "bundle" in the wing with a ground to a rib by the pitot - failed miserably. Then I ran a ground wire (not twisted at this point as Walt has recommended) - better, but still failed. Then I rerouted the ground farther from the magnetometer, twisted it around the power wires(s) near the magnetometer and got better results. It still fails Garmin's interference test for about 3 seconds during power up and power down, but I called it a victory.
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Old 03-29-2017, 06:56 PM
rockwoodrv9 rockwoodrv9 is offline
 
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Location: Meridian ID, Aspen CO
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I know there are differences between the 9 and 14, so is there a reason the magnetometer located in the wing rather than the back tail deck area? Im not flying yet so I don't know how mine will work, but there isn't nearly as many wires back there as by the pitot. There must be a reason. Thanks
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