Originally Posted by CambriaHobby

Mike
Even if I remove the mic I get the hum

That is strange.

I am wondering, Are you using a UHF LRS? (Like Dragonlink, chainlink, rangelink, Ezuhf, etc).

If so, Make sure that your Transmitter is placed 10 - 20 feet away from your equipment for testing purposes, and see if the noise goes away.



That noise that you are getting sounds like it is from an external source.

You can try that first, and then we will look at other options if it is not a 433 Mhz, UHF LRS that is causing the noise.

If the UHF is not the issue, then the next three things that I would look at, are:

Servo Noise:

Unplug your servos and see if the noise goes away.

If you are using digital servos, then it is conceivable that you are getting feedback.


Ground station recorder:

If you unplug your groundstation recorder, does the noise go away.

It is conceivable that you are getting feedback at the groundstation from the recorder its' self.


Transformers:

Are you powering any of your equipment by using a transformer?

If so, then eliminate any transformers from the system for testing purposes.



That gives you 4 things to look at immediately, to try to isolate the noise.

If it is not either of those, then we can look at some other options.

-Mike

Thanks Mike
I'll check it out
Mark

Originally Posted by CambriaHobby

Thanks Mike
I'll check it out
Mark

Good luck, let me know how it goes.

It is definitely an external source, even if it is coming over your video signal, like a internet router, cell phone, or something like that.

If you are using a 2.4Ghz transmitter, and a 2.4Ghz video, then that could possibly cause something like that.

I am just throwing things out there to be aware of because I don't know your system.

If you have listed your system, then I have missed it. I have been out of town for a few days, and it's hard to follow the forum on the smart phone.

Thanks again Mike
And yes. Lawmate 2.4 video with Dragon link.
I'll get it out of the house and see if it clears up.
Mark

Originally Posted by CambriaHobby

Thanks again Mike
And yes. Lawmate 2.4 video with Dragon link.
I'll get it out of the house and see if it clears up.
Mark

Dragonlink is 433 Mhz, so it is not likely directly interfering with the video, but it may be radiating a lot of noise that is interfering with your system.

Hi Mark,

i guess, that your wiring is made like in the manual ... a y-cable to support the voltage supply to the audio in/out of the osd.

i found out that there is a groundloop (gnd connection inside the osd) causing a noise on audio ... a report to et support is in action.

pls try to bring only the signal to/from the osd and bypass the power supply.

cu Thomas

Hi,
Here is my new setup, a single board with all the electronic.

http://www.rcgroups.com/forums/showp...ostcount=16863

Regards
Eric

Just listened to your video....the noise appears to be present even when you are NOT transmitting (flight battery unplugged) so I suggest looking at the RECV end of the setup.... especially look closely at ground connections since the sound is similar to a floating ground on an AV line....not exactly, but similar.
If you hook up a jumper clip to a known good ground (like power-supply/battery ground) then touch it to other grounds in the system (case, shields, av returns, etc) I suspect you will hear when the noise goes away....

Originally Posted by ron-sand

Are you thinking of the wiring scheme or the OSD configuration file?

Would you be willing to do both?
I was hoping you would document how to use the MFD with the EagleTree Pro?

Time permitted I will draw up a wiring cheme. There is nothing fancy to it but I have avoided ground loops where possible and practical. The camera/vtx wiring is shielded.

I can post the et-setup file, but it is not to far of from default as of now.

And you know that the problem I had with the Sunsky vrx might be a freak one....

Originally Posted by CambriaHobby

Hey guys
getting hum on my audio and can not hear the mic.
I have an ET and it is connected to a Lawmate 500mw tx. I installed the 10k resistor on the audio out and tried a 2.2uk cap on the video out from video to ground but when I connect the cap I lose my video.
Any suggestions?
Thanks.

Hello Sir,

Here is my video before

ET AUDIO NOISE 2 (2 min 27 sec)

And now.
https://www.youtube.com/watch?v=8CxBm4ot-q4


Here is my thread about this issue and the solution -> http://fpvlab.com/forums/showthread....ee-Audio-Noise


Just a question. 2.2uk cap? Can u send a photo of this capacitor? I donīt know what you mean by 2.2uk (uk? what is this).

If this is a 2.2uF capacitor, then your video will be out when connected. You need a 2.2nF or 2200pF (222 in the body) ort anything like this.


Maybe Iīm too older. I just know nF, uF, pF and this terminations (Farads).

Originally Posted by ron-sand

Time permitted I will draw up a wiring cheme. There is nothing fancy to it but I have avoided ground loops where possible and practical. The camera/vtx wiring is shielded.

I can post the et-setup file, but it is not to far of from default as of now.

And you know that the problem I had with the Sunsky vrx might be a freak one....

Thanks Ron, I really appreciate it!
yes, I'm using a Racewood, hopefully no problems then....

Did you ever figure out which piece of equipment the noise is derived from?


-Mike

Originally Posted by junioro16v

Hello Sir,

Here is my video before
https://www.youtube.com/watch?v=RiwfWRYaqz8

And now.
https://www.youtube.com/watch?v=8CxBm4ot-q4


Here is my thread about this issue and the solution -> http://fpvlab.com/forums/showthread....ee-Audio-Noise


Just a question. 2.2uk cap? Can u send a photo of this capacitor? I donīt know what you mean by 2.2uk (uk? what is this).

If this is a 2.2uF capacitor, then your video will be out when connected. You need a 2.2nF or 2200pF (222 in the body) ort anything like this.


Maybe Iīm too older. I just know nF, uF, pF and this terminations (Farads).

Thanks for the help guys.
So still working on the issue.
Here is what I've done so far.
on this video I removed the resistor from the audio out lead.
I installed the 2200pf cap
Here is the video

Resistor out cap in between gnd and video out (5 min 59 sec)

notice the ripple from the audio on the video with the resistor removed
at the end of the video I removed the video out feed from the osd
Is there a correct way that the cap installs?
Thanks
Mark