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Dynon SV background noise

Daida

Well Known Member
Hi folks!
I am talking about a full Dynon SV suit, SV1000, X83 COM, X26 XPDR, S2 Intercom and D6 as backup.
Tested my COM system today and noticed a unknown permanent background noise when the radio is powered.
Transmitting, receiving, radio squelch, intercom squelch, intercom conversation and everything else functions flawless.
However, when the radio is powered, the intercom is switched off (on makes no difference), squelch is set, nobody is making a noise......there is this background noise which sounds like the channel is open/active. It is hardly noticeable and you probably will not notice it once the engine is running, but it is there....
I can even hear my LED 12Volt strobes....
It is not ?dead? silent as i know from other com systems where the channel only opens up when the squelch level is exceeded.

Anyone with an idea what the cause is, whether it is normal or not, and how i can get rid of it?
 
Try running a separate ground wire directly to the SV1000 case or cases if you have a double display. There is a 6/32 tapped hole for that purpose on the case, I don?t remember exactly where.
 
Yes, i was in a Hangar with florescent lights, i will go back on Thursday and try it with the Hangar lights switched off.

Thanks for that hint, i hope it will be easy as this!

Whilst in the Hangar and option 1 doesn?t work, i will check for the seperate ground wire on the display case.

Thanks as well for your Input!!


I will post the outcome on Friday.


Anyone else any idea??
 
Florescent light will definitely create a loud noise in your system, might not be all but certainly most of your problem.
 
Additionally, you need to ensure that all of your audio devices have only a single path to ground. If there are multiple paths, that is called a ground loop, which can also introduce noise. It will also make your systems more susceptible to external noise sources like fluorescent ballasts.
 
I have been dealing with this same issue for quite some time also. I agree with all that has been said above; Florescent/LED lights, check grounds, etc., but give Dynon tech support a call and give them your serial number. It seem that some of the early Skyviews have an issue with producing "noise". Dynon has said they have changed out some circuitry that was the cause.
 
Yeap

I had the same issue with my Skyview, couldn?t isolate it at all and I tried everything.

Finally sent it back to Dynon, they knew the issue immediately and swapped out some of the circuitry and fixed the issue. 250 USD and no more issues.
 
I was in the hangar yesterday. Tried with all lights swirched off. Doublechecked ground wireing. No change.
Started to turn offthe individual components, one by one.
Isolated the COM X83 as source of the noise.
It is there as soon as the COM is powered.

Connections are according to the installation manual (i doublechecked again).
Running out of ideas...

I will contact Dynon today.
 
I have seen and solved this once before on a customer aircraft. Yours might be the same.

This will seem strange, but it is what it is.

Do you have the SV-GPS cable (4 wires twisted together) running alongside the VHF com antenna co-axial cable?

If so, seperate them by running the coax through a different route.

Even if you make a temporary cable to test it. You should be using RG400 coax, but even it will be affected.
 
Thanks for your reply, but the antenna coax and the GPS wites are seperated in my case.

I have the feeling as if some “squelch”/channel opening gate is set too low or the antenna(or a cable) is constantly receiving as i can hear my 12V LED Strobes when i turn them on as well.
Or i screwed up my wireing elsewhere.....

Anyway, I have contacted Dynon via their factory homepage and awaiting their answer.

Thanks anyway!
 
Didn't want to pile on...

I have been monitoring this thread, but didn't want to pile on as others have been giving some good advise regarding the grounding issues. I do have some questions? With regards to the intercom install, is it our wiring harness? How are the strobes grounded? When you say it quits with the X83 un-powered, is the intercom still powered? I will also reply to you when I am back at work on Monday and can do some research, but will also keep this thread updated as well in case it may help others.
 
Hi Don,
thank you for response.
Here are the answers to your questions.

It is NOT your wiring harness, i made up my own. Only the network cables are the factory ones.
Strobes are grounded at the forrest of tabs (FOT). (a single wire grounds COM T8 PIN 22, PIN 19 and PIN 2 COM PANEL there as well)
The intercom was not powered.

I still have to check if PIN 1 from the INTERCOM S2 is solely connected to PIN 1 from the COM T8 (as shown on page 17-11 SV installation guide). I may did it wrong and ran a wire directly to the FOT/ground as shown in the S2 installation guide page 2-3?
Plane is 30min drive away from home. I will find out and post what i find out.

So long...
 
Problem solved!

I was at the hangar, chasing the gremlin.
Finally succeeded and got rid of it!

I had a ground loop!

I wired it up the wrong way.

PIN 1 from the INTERCOM S2 was NOT solely connected to PIN 1 from the COM T8 (as shown on page 17-10 SV installation guide). I additionally ran a connection from INTERCOM S2 PIN 1 directly to the FOT/ground (as shown in the S2 installation guide page 2-3) which closed my ground loop.

As i am not a professional, i guess i interpreted the drawing incorrectly.

Problem solved. Case closed.

Thanks everyone for your inputs!
 
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