SDI earthing/grounding.

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daver2

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  • Real Name: Dave Roberts

SDI earthing/grounding.

PostSun Apr 14, 2024 1:09 pm

We have an ATEM HD Television switcher unit and various SDI splitter boxes, SDI cables and SDI to HDMI converter boxes. All of the equipment is from BMD.

Many years ago, when we installed the ATEM, we were driving an existing set of projectors. We had some occasional signal dropouts. Nothing major, but we put it down to the poor projector USB port powering the SDI to HDMI converter.

We have recently upgraded the projectors to 86" monitors and found we have exactly the same problem...

We have been swapping one thing at a time to try and isolate where the problem is. We are slowly eliminating things, and it is looking like an earth/ground issue.

Unfortunately, the problem is not 100% repeatable.

I have everything fed from a single distribution board - driving the equipment from separate breakers from the DB. An electrician has installed (and certified) the mains installation.

Basically, we have an ATEM driving a BMD 8-way splitter with insulated SDI cable runs to the monitors. Each monitor has a BMD SDI to HDMI converter (fed from a USB3 power cable sourced from the monitor itself).

As we suspect an earth/ground issue, what are the recommendations regarding the earthing/grounding of the SDI shield?

It looks like the mains PSU feeding the SDI splitters is a class II device (so no earth).

Any help gratefully received...

Dave
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daver2

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Re: SDI earthing/grounding.

PostSun Apr 14, 2024 1:12 pm

Incidentally, we are running at 1080p50.

Absolutely no problems with our cameras (inputs) to the ATEM.

Dave
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KirillH

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  • Real Name: Kirill Kheifets

Re: SDI earthing/grounding.

PostTue Apr 16, 2024 3:15 pm

Hi, Dave! I am also interested in this question. Suddenly, six months ago, problems with projection failures began. But for me, it's really a Problem - when the projection disappears in the middle of the performance "The Snow Queen". Although this happens for a few seconds, the children see how the kingdom of the Snow Queen turns into an exhibition of tulle. And I have a lot of complaints about the work of my department. It is strange that six months ago there was no such problem. The technology of preparing the scene has not changed. The equipment is the same. Total: the computer has a BM DeckLink Quad, at the ends of the lines there are Micro Converters SDI-HDMI. Sometimes, after switching the system, some projectors do not provide images. We change the converters - the image appears. We put the suspicious converter aside. But next time it is this suspicious converter that turns out to be quite workable. In general, I would also like to know what to do about it?

And one more thing: often, during installation, while connecting the signal cable to the converter, I am slightly electrocuted. Maybe it's a static discharge, but that also makes me think that it's about grounding. Rather, in creating a common "ground" - on stage and in the video cabin
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daver2

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Re: SDI earthing/grounding.

PostFri Apr 19, 2024 5:48 pm

Hi,

I am going to try earthing/grounding the screen of the SDI cable at the 'sender' end to see if that fixes our problem. The advantages of trying this (from my perspective) is that all of the SDI cables are at a common point.

We have just changed the SDI cable between our ATEM and the SDI splitter, so we are testing that out first.

Dave
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Howard Roll

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Re: SDI earthing/grounding.

PostMon Apr 22, 2024 4:41 pm

Building codes in the US dictate that patch bays using shielded cables like coax have external earth grounds. SDI is grounded by design, there shouldn't be any additional "earthing" necessary. If you run multimeter across the AC ground, the coax shield, or the XLR ground you should see continuity indicating that these are all earth grounded. The neutrals are still grounded it's just a different path.

Good Luck

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