Jumpy video in ATEM TS. Coax cable run limit?

Hi,
I'm setting up my ATEM Television Studio in a large-venue room pre-wired with coax. I have 9 runs of coax to various points in the room, 3 of them being all the way to the front of the room, maybe 400' - 500' or greater. I took a camcorder and mini converter around to each position to test. Of the 3 longest runs in the room, it works fine on one, but on the other 2 long runs the video is jumpy, coming in and out, going blank every second or so. It behaves as though there is a short in the cable but even with me holding the connections solid it still jumps in and out.

Is there a max limit to the run of coax I can use?
Has anyone else experienced this kind of problem?

Thanks.

their are limits ...

read through the forums and also read the wiki about the smpte standards ... this has nothing to do with blackmagic but with all smpte compliant equipment.

their are standards for various resolutions ... the quality of your coax is also a variable ... yes all coax is not created equally.

in general though 100 meters for hdsdi / 300 for sd sdi without being reclocked and through no other barrels jumpers etc.

Thanks. Can anyone tell me if these are the symptoms (video coming in and out) that would occur in a cable run that was too long?

Yes it definitely is. I tested an analog to SDI mini-converter sending 1080i component video through the mini-converter to m ATEM TVS. At 300' it worked perfectly. When I added another 150' onto it, I experienced the exact same thing you described. When I tried 400' total coax, it seemed pretty stable. This was using Gepco SDI-rated cable and going through several barrel connectors. I think the spec is a little conservative but very safe to use as a guideline.

I'm setting up my ATEM Television Studio too ,now can get some details thx

100 meters is a little over 300 ft ... so yes you can go longer than 300 ft ... and it is spec will it go longer, yes, are their chances you could run into issues, yes and no. the spec is conservative but its also pretty safe to say that at 300 ft or less you will always get it to work ... at greater distances your just asking for trouble ... any blackmagic design sdi unit will reclock the signal and get you another 300 ft ... or fiber is really quite cheap depending on what your wanting to do ... per ft its less than quality coax in a bulk situation and can get you essentially unlimited distance.