Long SDI cables / 1M/E PS 4K strange blinking

Hi guys, I have really strange problem, that had me really stressed.
I'll be thankful for any advises, cause I run out of ideas what's wrong.


First - our basic setup includes ATEM Television Studio HD, 4 CANON XF205 cameras and other stuff. Cameras are connected to the switcher by 100 meter SDI cables - Belden 1855A. The setup works really well, even in tough conditions and didn't have any problem so far.

Now comes the funny part - we also have ATEM 1 M/E PS 4K. It always stays in the studio and is working really fine. I decided to install it in our mobile system, cause it has more useful options that we need.
After installing I run few tests in the studio and everything went well, although I didn't use the long cables.
Then we went to broadcast some event and 2 of my cameras started blinking constantly. I tried to change all cables, cameras, inputs, settings...I also checked for internet routers nearby that could cause that. And I found that only inputs 1,3,5 are blinking. The other inputs seemed to work fine. I checked the inputs with the same source and cables. So I thought there is problem with the inputs. But these inputs were working fine with much shorter cables in the studio. Yep, I tries connecting something with short cable and all the inputs were working fine again. Also, I tried connecting one of the cameras to one of the problem inputs using optical cable and two SDI-FIBER converters. There was no problem. So, you could say, the problem is with my cables or their length. But then, why do they work with the other inputs and with the ATEM TVS HD ?
Weird...


p.s. So I had to finish the event using channels 2,4,6,8. They worked fine...but two of them tried to blink for a really short time once or twice. But I can't believe all my cables are bad (since they worked fine week ago). Maybe after all the 1M/E is more sensitive to cable length that the TVS HD?

The short answer is: The 1ME can do 4k.

For that it needs to use a wider range of frequencies on the SDI inputs. Even if you use it in HD mode the inputs are still open to those enhanced fequencies. That leads to the problem that the 4k version of the ATEM line is much more sensitive to long cables / interference.

The Belden 1855A is not a good cable for long runs! It is designed for shorter cables not for long runs. Use the proper cable if you want 100m like Belden 1694A.


You have three choices:

#1 Use Fiber
#2 Use better shielded SDI cable like Belden 1694A
#3 Use much shorter cables


Cheers

Robert

I also put re clockers on many of my inputs before going into the switcher. Stupid but easy fix.

I also put re clockers on many of my inputs before going into the switcher. Stupid but easy fix.

Thanks, can you give me more details on that?

The short answer is: The 1ME can do 4k.

Thank you very much. You really answered my question, although this made my life much more easier.

Finding the solution looks like mission impossible right now (unless I can do that thing with the reclockers)

I'll give some details about what I did last night, and maybe someone can help ? Please

More detailed explanation follows, sorry for that and thanks for your time.

My first choice when designing the system was optical cables. Even few of the people here were really nice to give me many advises and tips. However, at the end we decided to stick to coaxial SDI cables as cheaper, easier to use and less risky way to work. My first choice was Belden 1694. Price difference was not a problem. But friend of mine, TV engineer, advised me on 1855 as a cable with the same parameters, but lighter and more flexible. His words. So we got 1855 and the system worked fine so far even in tough conditions, working outdoors in extreme weather conditions and many people stepping on the cables and so on.
So, after I got the answer here, the obvious choice is to go back to the ATEM TVS HD, but...
Last night we had important event and the other switcher was in the office, 500 kilometer away. So we hired experienced engineer from another rental company to solve our problem. He brought some switcher, it didn't work at all with my long cables - not even single blinking, just black screen. The guy checked my cables, said I did the connectors properly, then measured the cables with some testing device and said they are too long and the signal is to weak.
Solution? Split one of the 100 meter cables into 2 50 meter cables. They worked, so we used the 1 M/E 4k with 4 cameras - 2x50 meter cables, 1x20 meter cable and 1xoptical cable with converters. Everything went perfect. But...it was the first time we used 4 cameras, highlight repeater, computer for graphic/titles/animations and another computer for playing some videos. My bosses were happy with that, so they want me to keep working that way. But there is no way to do that with the ATEM TVS HD - it has only 4 SDI inputs and I need at least 6. Also, it has just 1 aux output and last night I needed the 3 aux outputs - 2 to feed the repeater and 1 to feed the video screen on the stage.
So I really have to find the solution to use the ATEM 1 m/e 4K and still use long cables (we need them in some cases), but right now the budget is limited and I cant buy 400 meter of Belden 1694 or optical cables (besides I don't think the boss will be happy). I have few ideas how to solve the problem.
1. Making the cables 80 meters long, hoping it will be ok.
2. Using some sort of devices to "amplify" the signal on the camera end - not the best idea with the mobile camera operators - I can't stick all kind of devices on their back.
3. Using some sort of devices to "amplify" the signal somewhere in the middle of the cable - not a good solution when working outdoors or crowded area.
4. Reclocking - I don't understand it right now, but I wait for answer and also I will read a bit.
5. If there is some way to "downgrade" the switcher or "change" the sensitivity of the input.
That last one may sound stupid, but the last night the engineer asked me if there is something in the settings that will allow me to do something like that.

Thanks for your time and any advises/ideas !

Hey,

I would definitely shorten the cables to about 80 meters.
But keep in mind that the combination of SDI output and input equipment might play a role as well.
Some cameras SDI output may only be able to run 50 meters to your ATEM, and some might be able to run twice as long.

Also the SDI input equipment has different sensitivity.
Many ATEMS (in my experience) are not very sensitive, and require a strong SDI signal.
Other equipment can be more sensitive.
For instance, if I have a blinking source on my ATEM I can usually reclock it with a Decimator converter (I use the MD-HX) or a Smartview monitor at the destination (right next to the ATEM). And then just run a short cable to the ATEM input.

I've been thinking of trying the Decimator DMON-6S to reclock - that would give you 6 reclockers in a small package. Not a pretty solution, but it might work

you can put a bm micro converter sdi to hdmi into the middle of the cables(you use sdi in and sdi out and you dont need the hdmi output) they reclock the signal and you get 50 to 70 more metres with belden 1855. but you need electric power there and someone who put plugs in the middle of your existing cables.

you can put a bm micro converter sdi to hdmi into the middle of the cables(you use sdi in and sdi out and you dont need the hdmi output) they reclock the signal and you get 50 to 70 more metres with belden 1855. but you need electric power there and someone who put plugs in the middle of your existing cables.

Thanks! I'll try that when I get to the office. I make my cables (I have proper tools), I have converters and I have long power cables. The only thing that bothers me is using this system outdoors, especially during rain and snow. Will it work if I put the convertor on one of the two ends of the cable - the switcher end or the camera end?

No. The signal has to be resynced when it is good enough to be resynched. After 100metres too much of the signal has been lost.

Yes, rain and water is a problem. The better solution are better cables without the need of resynching.

No. The signal has to be resynced when it is good enough to be resynched. After 100metres too much of the signal has been lost.

Yes, rain and water is a problem. The better solution are better cables without the need of resynching.

Thanks again. I already have idea what to do, but your idea sounds good. I may try to make some sort of permanent, sealed box in the middle of the cable where I will put the converter. I may also run one more cable with 5 volts power (for the converter) along with the other two cables that go to very camera. I actually have intercom cable going to every camera and it contains power for the intercom unit. I'll check the voltage and it will make the task easier if I can use that power also for the converter.

If you decide to buy new cables, here you can get some numbers: https://www.belden.com/blog/broadcast/t ... erformance

If you decide to buy new cables, here you can get some numbers: https://www.belden.com/blog/broadcast/t ... erformance

Thank you. That chart looks very good, wish I saw it earlier. It says I should use maximum 66 meters of 1855a in my case. I guess I shouldn't trust my friend who advised me on 1855 . 1694 is much better for HD and it is ok to use maximum 113 meters which is enough for me. Unfortunately I can't buy any new cables right now and my boss is not very happy, so I'm back to the office (instead of using my free days) and started few tests to solve the problem.

I need to comment few more things. Speaking honestly I'm desperate right now, so I really appreciate all the help and advises I get from all of you. Thank you for your time!

I connected SDI-HDMI BMD micro converter into the switcher input and the 100 meter cable goes into the converter input. I know it's not the right way, I did it just to see what happens. Not a single drop so far. The only explanation I find is this:
TV Studio HD switcher works fine with my cables, because its inputs are not so sensitive.
1 m/e 4k doesn't work well with my cables, cause the inputs are more sensitive. Decklink 4k card also doesn't accept the signal from my cables. So I guess the input of the converter is not so sensitive and connecting it at the end of the cable helps fixing the level of the signal enough for the 1m/e to work with it. I tried again connecting the SDI cable straight to the switcher - terrible blinking. Using the converter this way (at the end of the 100 meter cable) looks like the right decision right now and also really easy, quick and cheap. But I'm not sure if I should trust it.
And since I have small budget and very limited time before the next event, I came up with another idea. I hope you can share your opinion on it. Here it is:
I go back to the ATEM TVS HD switcher - it works well so far with my 100 meter cables. The reason I replaced it with the 1m/e PS 4k is because I needed 2 extra aux outputs and 1 extra SDI input in order to connect highlight repeater. I think I can do that different way. two of my cameras will go into BMD SDI-HDMI microconverter. The HDMI out will go to one of the HDMI inputs of the switcher. The loop out will go to the repeater. The repeater is actually very powerful computer with Decklink cards and proper software. If loop out of the converter is good enough for the ATEM 1m/e it should be good enough for the decklink inputs. In the same time, connecting 2 cameras to HDMI input, will free 2 SDI inputs.

Does it look ok? I'm going to connect that now and try. The only problem is the repeater is not here. We don't have it, we hire someone ho has it and we won't meet before the next event.

p.s. Another reason I want to go back to the TVS HD is the headphone output. I'm not only the engineer of our team. I'm also the sound engineer. The headphone output helps me monitor the signal before it goes out of the switcher for broadcasting or recording. I can't do that with the ATEM 1m/e 4k and it really bothers me. Well, I use one SDI-analog converter but sometimes I need it for something else and it's too much bother anyway.