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Dynon comm constant sq break/ static

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ERJDriver

Well Known Member
In the continuing saga...rv8 with fresh install by yours truly, had issue with comm antenna wire, got that fixed as I'm receiving people that are 50+ miles away.

Now the issue at hand is a constant RX on screen with a static like noise when ALT is on.

Alt turned off, 90 percent of it goes away with squelch only broken every now and again.

Wired per dynon as far as comm and intercom with Shields etc.

What would cause this? Heard RF from main shunt feed which passes right next to the comm coax, or the alt filter of some sorts.


Help.

Anddddd go
 
Adjust your receiver squelch down until it goes away. Turning down the receiver squelch will reduce receiver range, however that may not be your problem.
 
Aircraft Spruce has a wide variety of filters to deal with this issue. Search alternator filters on Spruce website.
 
Well it’s the LED landing lights it seems. Is there a way to ground them differently to where I don’t get feed back?
 
The constant-current power drive circuits for the LED's are electrically noisy. They will send that noise backward from the power circuits into the power and ground wires supplying power to the drive circuit. You can insert ferrite cores or wrap the wires around a toroidal ferrite core to knock down most if not all of this noise. You will want to install the ferrite cores as close as possible to the LED power drivers, as any power/ground wire not protected is serving as an antenna broadcasting this noise and your radio is picking it up. Try to keep that antenna as short as possible by placing the ferrite as close to the drive circuit as possible.
 
airguy said:
You can insert ferrite cores or wrap the wires around a toroidal ferrite core to knock down most if not all of this noise.
Click to expand...
Airguy makes an important point. For suppressing noise a lot of people stop at capacitors but especially for higher frequency noise components ferrite cores are your friend. Whether or not you know it, you see these all the time on computer cables in everyday use. In my case I had noise getting in to my intercom. I made a pass-through connector adapter with ferrite cores for the intercom connector. It was very effective at making my noise problem go away. It would have been more satisfying finding the source of the noise but at least I was able to stop it. It is interesting, and in retrospect not unexpected, that you found your noise source to be the LED lights. I'm going to file that nugget away!
 

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Ordered ferrite chokes. We'll see what happens.

I'd rather not replace the lights. Should know by Friday afternoon
 
Conventional strobes use shielded wire from the power pack to the bulbs, because they are really (electrically) noisy.

Some ideas:
At a minimum, see how far your landing light power wire is from your audio and antenna wires. Same bundle? Move it.
are the antenna wires RG-400 (double layer shield) or something else?
Change the LED power wire to shielded.

Also, FYI, LED constant current drivers aren't noisy because they are constant current... they're noisy because they are switching regulators.
 
blaplante said:
Conventional strobes use shielded wire from the power pack to the bulbs, because they are really (electrically) noisy.

Some ideas:
At a minimum, see how far your landing light power wire is from your audio and antenna wires. Same bundle? Move it.
are the antenna wires RG-400 (double layer shield) or something else?
Change the LED power wire to shielded.

Also, FYI, LED constant current drivers aren't noisy because they are constant current... they're noisy because they are switching regulators.
Click to expand...
No where near each other in bundle, rg400
 
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