MGL EFIS RF/EMI Problems

Discussion of aircraft electrical system design, construction, and problems.

MGL EFIS RF/EMI Problems

Postby NWade » Wed Dec 13, 2017 3:44 pm

Has anyone else experienced a noisy MGL EFIS like what I demonstrate here? I'll be contacting their support shortly, but wondered if folks here are familiar with this problem. It certainly doesn't seem like a ground-loop to me...

https://www.youtube.com/watch?v=kg8bZ5wZ3bk

Thanks for any informed thoughts or first-hand experience you can speak to!

--Noel
Sonex #1339
Last edited by NWade on Sat Dec 16, 2017 9:23 pm, edited 1 time in total.
NWade
 
Posts: 346
Joined: Mon Aug 08, 2011 3:58 pm

Re: MGL EFIS RF/EMI Problems

Postby WaiexN143NM » Wed Dec 13, 2017 4:01 pm

Hi noel,
By noisey do you mean static bursts in your radio headset jacks? We have the dynon set up in #143 ,yes the efis puts out lots of rfi. The radio/intercom/headset harness MUST have shielded wires. We chased some rfi for a year, finally resolved. We have an Xcom radio.when talking to ian, owner of xcom, he said the MGL products put out alot of rfi. Im not bashing their product, just repeating what a radio mfgr. Told me. Good luck. Will you make OSH2018?
Added: just watched your video, thanks. We origionally had a dynon radio/intercom, but could never get rid of the noise. When sitting in the plane and reaching touching the panel or efis we got a constant static in headsets. I finally took out the dynon radio, installed a xcom radio in the back in turtledeck rollover rib , then the xcom remote head only in the panel. Connected to radio by a shielded wire with a 3.5 mm plug pins. No more rfi works well.
WaiexN143NM
Michael
Last edited by WaiexN143NM on Wed Dec 13, 2017 4:16 pm, edited 1 time in total.
WaiexN143NM
 
Posts: 669
Joined: Mon Sep 15, 2014 1:04 am
Location: SF CA, Tucson AZ

Re: MGL EFIS RF/EMI Problems

Postby NWade » Wed Dec 13, 2017 4:08 pm

Michael -

No, its not static bursts or noise in my headset. Most of the time people talk about noise as static or whines in their earcups over the intercom. This is NOT THAT PROBLEM (i.e. not a typical ground loop). This is the instrument putting out so much radiation that the COM antenna is picking it up and thinking its a transmission from another radio! Anytime the EFIS is turned on, the COM thinks its receiving a VHF broadcast. And it happens across all VHF frequencies. And it happens using the panel-mounted radio as well as with Handheld radios if they're within about 3 feet of the EFIS.

Thanks,

--Noel

P.S. I'm hoping to make OSH 2018! I am just about a week from first engine start, and after that I've just got brakes, the finishing bit of the canopy, various fairings, control-rigging, and misc. close-out work (i.e. triple-check all cotter pin locations and install safety-wire on appropriate parts) to do... Of course, I also have to find a new job between now and then, too. :-P
NWade
 
Posts: 346
Joined: Mon Aug 08, 2011 3:58 pm

Re: MGL EFIS RF/EMI Problems

Postby WaiexN143NM » Wed Dec 13, 2017 4:20 pm

Hi noel,
Very interesting. Do you think moving the antenna aft would help?
And keep at it! Looking forward to lots of new sonex aircraft on the flightline osh 18!
WaiexN143NM
Michael
WaiexN143NM
 
Posts: 669
Joined: Mon Sep 15, 2014 1:04 am
Location: SF CA, Tucson AZ

Re: MGL EFIS RF/EMI Problems

Postby NWade » Wed Dec 13, 2017 5:18 pm

More evidence that this is radiated signal: If I put a piece of 0.025” aluminum just in front of the antenna (blocking line of site to the EFIS display panel) and touching the turtledeck (so stray signal can drain to ground), the “incoming signal strength” on the COM display drops to 0. I can still hear legitimate transmissions when I do this (so I know I’m not just shorting something out).

Also: Other airplanes on my field confirm that my transmissions are strong and free of noise.

I’ll post here if I get any good info from MGL; other thoughts from experienced Sonex folks is still much appreciated!

—Noel
NWade
 
Posts: 346
Joined: Mon Aug 08, 2011 3:58 pm

Re: MGL EFIS RF/EMI Problems

Postby daleandee » Wed Dec 13, 2017 9:09 pm

NWade wrote:More evidence that this is radiated signal: If I put a piece of 0.025” aluminum just in front of the antenna (blocking line of site to the EFIS display panel) and touching the turtledeck (so stray signal can drain to ground), the “incoming signal strength” on the COM display drops to 0.


Two things come to mind that I will pass on for your consideration.

1) I have my comm antenna mounted on the bottom of my taildragger just ahead of the main spar tunnel. I'm using a stainless steel whip and LMR-240 coax. My radio is a Flightline 760 and I use the MGL singles. On the belly my radio sends and receives extremely well. Got a "loud & clear" radio check the other day from pattern altitude from another pilot 45 miles away. Ground ops work well also with a belly mount antenna.

2) With that much RFI coming from that EFIS unit you should consider your own safety & health. I have no way of knowing how much or what frequency of radiation you are dealing with but it's getting into the antenna behind you so you will be getting a good dose of it yourself.

Dunno if this helps,

Dale Williams
N319WF @ 6J2
Myunn - "daughter of Cleanex"
120 HP - 3.0 Corvair
Tail Wheel - Center Stick
Signature Finish 2200 Paint Job
165.2 hours / Status - Flying
Member # 109 - Florida Sonex Association
Image
daleandee
 
Posts: 566
Joined: Fri Feb 01, 2013 6:14 pm

Re: MGL EFIS RF/EMI Problems

Postby Fastcapy » Wed Dec 13, 2017 9:58 pm

Yes, my Xtreme is VERY noisy. I rewired my radio, triple checked for ground loops, installed a bunch of ferrite beads, everything I could think of yet I still had a crazy amount of noise. I have to turn the squelch way up on the radio to make it so I can even hear it incoming transmissions. I pulled the power from the Xtreme and poof the noise went away...

When I take up passengers they ask if their cell phones will interfere with the instruments, I laugh and say no but the EFIS will really interfere with your phone!

I talked to mgl about it at Airventure last summer and they didn't have much to say about it... I am not particularly happy with MGL for some other issues I have been having with their products lately even after getting my SP6 back from them I still can't get it to work correctly...
Mike Beck
Oshkosh, WI (KOSH)
Sonex #1145 N920MB
Std Gear, Modified Aerovee, Rotec TBI, Dual Stick, Acro Ailerons
MGL Panel
Airworthiness: 10/24/13, First Flight: 05/18/14
Fastcapy
 
Posts: 282
Joined: Sun Jan 12, 2014 11:45 am
Location: KOSH

Re: MGL EFIS RF/EMI Problems

Postby DCASonex » Thu Dec 14, 2017 9:29 am

Quick way to confirm that it is a radiated signal from your EFIS and not something in the wiring, If radiated, it should have same noise effect on adjacent planes or hand held coms.

David A.
DCASonex
 
Posts: 520
Joined: Mon Sep 12, 2011 8:04 pm
Location: Western NY USA

Re: MGL EFIS RF/EMI Problems

Postby Gripdana » Thu Dec 14, 2017 10:26 am

This may be off base as your set up may be different than mine but here is what happened to me. I have an MGL Xtreem EFIS and an MGL V10 radio. I developed an intermittent strong noise that made it impossible to here any thing on the radio. I tried to track it down and decided to change the VHF antenna from the bottom to the top of the plane. Then while testing the change (the noise was still there) I noticed that the battery voltage was low and I was pulling a heavy load. I decided to un plug my USB devices from the charger port to reduce the load and the noise went away. I had a 2 port USB charger mounted in the panel. It was kind of cheap. I decided to change it out for the cigarette lighter type and use a plug in USB charger. I figured that the noise was generated from the electronics in the USB port and being able to change the USB portion I could get one that is better made and not produce any noise. So far it has worked well. I have about 100 hours on the new set up.
Dana Baker
Scratch Built
First Flight March 8, 2015
Sonex #1534 - N1534S "Aluminum Foil"
Aerovee-Dual Controls-Tail Dragger
Gripdana
 
Posts: 462
Joined: Fri Jan 11, 2013 5:59 pm

Re: MGL EFIS RF/EMI Problems

Postby NWade » Thu Dec 14, 2017 2:15 pm

DCASonex wrote:Quick way to confirm that it is a radiated signal from your EFIS and not something in the wiring, If radiated, it should have same noise effect on adjacent planes or hand held coms.

David A.


Thanks David. Per the video I posted earlier, the broadcasted noise is definitely picked up by handheld radios within ~3 feet of the EFIS screen. :-/

—Noel
NWade
 
Posts: 346
Joined: Mon Aug 08, 2011 3:58 pm

Next

Return to Electrical System

Who is online

Users browsing this forum: No registered users and 1 guest