To reduce video noise, it is often recommended to add a common ground between VTX and camera to avoid ground loops. What is a ground loop, how does it add video noise and how can a common ground negate its effects. Thanks.
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asked Apr 14, 2020 at 20:50
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1 Answer
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If enough current flows and two ground pads are far enough apart, there might be a voltage difference between them because of the resistance in the PCB:s traces. That's called a ground loop.
As for why that causes noise; if the camera and the VTX have different reference points, a signal sent from the camera won't be received correctly by the VTX, and since a PAL or NTSC (The types of video that is used for analog FPV systems) signals use less than one volt, even a small in potential can cause video noise that will appear as horizontal bars moving vertically.
Here is an some more information if you would like to read more about it
answered Apr 14, 2020 at 21:06
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$\begingroup$ Excellent, thank you for that explanation $\endgroup$ Apr 14, 2020 at 21:06
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$\begingroup$ No problem. I'd be happy if you marked this as the answer if you think it is! $\endgroup$ Apr 14, 2020 at 21:12
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$\begingroup$ I’m going to leave this question open for a little longer to invite more answers, however I feel that you have explained it very well so will be happy to mark this as the answer shortly. Thanks! $\endgroup$ Apr 14, 2020 at 21:15