Radio Noise

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Radio Noise

Postby n163yx » Wed Sep 07, 2016 10:06 am

The Jabiru 3300 in my WAIEX is putting unbearable RPM related noise in my Dynon radio. Almost all the noise seems to be coming in through the antenna. I have tried two different filters on the antenna, resistor spark plugs, ferrite beads on everything going through the firewall, an in line Ameriking (2 pound!) filter on the radio power wire and a new ignition harness and new rotors. This has been going on for a year and It's driving me crazy. Any suggestions? Anyone have this problem and solve it? Any help greatly appreciated. Thanks. Don King
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Joined: Mon Sep 08, 2014 7:56 pm

Re: Radio Noise

Postby gammaxy » Wed Sep 07, 2016 11:39 am

Were you able to try the troubleshooting steps mentioned by Jon Gillis on your previous thread?


If so, do you know if it is ignition or alternator related? I'm assuming unplugging the microphone had no effect since you are pretty sure the noise is coming in the antenna.
Chris Madsen
Aerovee Sonex N256CM
Flying since September 2014
Build log:
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Re: Radio Noise

Postby sonex1374 » Thu Sep 08, 2016 10:55 am


If you've tried all those changes (new plugs, wires, caps and rotors, beads), it may be something simpler. How is your radio antenna routed up the sidewall and behind the panel? If the antenna feed line crosses other wires they can affect each other. An example of this could be your cigarette lighter plug feeding noise into your radio, or your radio feeding noise into your EFIS causing fluctuations every time you transmit. The key point here is that routing makes a huge difference. You should review your antenna routing and look for ways to change or improve separation.

Next, check the condition of your antenna ground to the ground plane. Is there corrosion starting under the antenna base? Or under the ground lug? Bad antenna grounds will de-tune your antenna and may be a problem.

Also, where is your radio antenna mounted? You may need to move it to another spot. Try removing your antenna from the airplane, mounting it on a temporary aluminum ground plane (i.e. a 12-24" square or diameter piece of metal, or crossed strips, or whatever), and moving it away from the plane a bit. If that improves things, maybe a new location on the plane will help.

Lastly, check the condition of your antenna feedline. Damage to the line or a badly crimped connector can let RF noise in or out. Inspect it carefully for kinks (breaks in the insulation), abrasions, or bad ends.

Good luck with your troubleshooting.

Jeff Shultz
Jackson, MS
Sonex TD, 3300, AeroInjector
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Re: Radio Noise

Postby Gripdana » Fri Sep 09, 2016 9:55 am

I had noise develop in my radio. After changing the antenna and its location I found the noise coming from the USB charger port. Found the problem by accident when I unplugged from the port while flying. I changed to a cigarette charger with a USB insert and the noise went away.
Dana Baker
Scratch Built
First Flight March 8, 2015
Sonex #1534 - N1534S "Aluminum Foil"
Aerovee-Dual Controls-Tail Dragger
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Re: Radio Noise

Postby WaiexN143NM » Fri Sep 09, 2016 5:21 pm

Hi all,
Just some info on radio noise. We are getting some intermittent radio noise from our dynon efis into our dynon radio/ intercom. The dynon guys at oskosh suggested have a seperate grounding block only for radio/intercom. They said alot of issues can be traced to good grounding. We'll give it a try soon.
Off topic, sunday is 9/11 , lets pay tribute to all the heros on the flights that day. I was working at KMRY(twr/tracon) that day. The few days after that were very erie and quiet. Lets hope for an incident free sunday. Going to watch 'sully' on sunday. Reviews sound good.
Take care all,
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Location: SF CA, Tucson AZ

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