Long HDMI cable runs

[hunterjwizzard]

Hi folks,

I'm new to the forums and didn't see anywhere to introduce myself or anywhere that looked like a better for, so I figured I'd try here. I'm sure I'll fit right in with all the weird things I do.

Anywho. I'm presently attempting to upgrade the hardware in my main workstation and have hit a roadblock. Specs here:

Asus Z10pe-D16-WS
2x Xeon E5-2643 v3s
64gb RAM
Windows 10 Professional - fresh install
Monitor is an LG-43UD79-B
Current graphics card is nVidia GTX 1070(there are two but not in SLI)
1000w PSU - dont know the brand offhand but can get it.
KVM: TESmart 8 port

PC in question is using a DP to HDMI adapter on the first display port of the card. Have tried both the latest driver and some older ones from another PC that is working.

Now here's the tricky part: the PC is in one room and the monitor(s) and desk are in the other, with a 50' HDMI cable connecting from the PC to a KVM at the desk and KVM to the monitor. I've been running this setup for years and it has worked well, works well with other systems(also in the other room) and worked previously for this specific system with a different graphics card. However, I really wanted to upgrade to a better card, this being my second attempt.

Basically, I cannot get the system to push a 4k resolution to the monitor for love or money. Seems to be isolated to this specific machine with these specific graphics cards, since the last card(AMD FirePro w7100) did 4k without many complaints. I am typing this to you from a different computer that uses the same kind of cable but an additional splitter in the mix, which gets 4k resolution without any problems. I tried hooking the problem workstation to the same setup, it did not help.

If I do a straight shot from the HDMI out(not DP) on the card directly into the monitor, I get 4k. This is a single 50' run, no extender, spliter, or switcher. However, this is not an acceptable solution because I need to be able to go through the KVM. I get that I'm trying to something atypical, but if it works for other stations why can't it work for this one?

 

[i386]

(Did you upgrade the displayport firmware on your gpu? Nvidia released some time ago a tool to upgrade/fix displayport bugs)

Did you use the displayport to hdmi adapter with previous builds? If no then it's probably your displayport adapter

 

[nasi]

but if it works for other stations why can't it work for this one?

Maybe your DP->HDMI adapter isn't producing enough voltage/power for such a long run. So the signal at the end of your long cable isn't good enough anymore for your KVM to recognize it.

Did you use the same adapter with your FirePro W7100?

You could try a better HDMI cable with bigger diameter, a so called "active HDMI cable" or an active powered signal repeater - that's what your splitter in the other installation is presumably doing if it's having it's own PSU.

 

[hunterjwizzard]

(Did you upgrade the displayport firmware on your gpu? Nvidia released some time ago a tool to upgrade/fix displayport bugs)

Did you use the displayport to hdmi adapter with previous builds? If no then it's probably your displayport adapter

I am using the same DP adapter. Have also tried a DVI to HDMI on the DVI port and a different(powered) DP adapter to roughly the same results.

I will give that upgrade a try, though, that sounds promising.

Maybe your DP->HDMI adapter isn't producing enough voltage/power for such a long run. So the signal at the end of your long cable isn't good enough anymore for your KVM to recognize it.

Did you use the same adapter with your FirePro W7100?

You could try a better HDMI cable with bigger diameter, a so called "active HDMI cable" or an active powered signal repeater - that's what your splitter in the other installation is presumably doing if it's having it's own PSU.

Yes same adapter. In fact the firepro was using 2 of these adapters, though only 1 was producing 4k. The cables are pretty good; I have a few other systems doing 4k over the exact same cables(bought 6 of them). Running a new cable is less than ideal but if it comes down to that I may bite the bullet. Thing is if I can get it to work on the same cable with another system I feel like it shouldn't be neccessary.

I do have a powered 4k splitter on the end to act as a repeater/signal booster between the 50' cable and the KVM. Its a different brand than the the one on the other PC thats working. As I test later I may hook the working PC up to the problem chain and see.

Going to look for that DP update first, though.

 

[hunterjwizzard]

Well, there's progress. After the firware update, the computer can now "see" the native resolution if I plug in to the HDMI port(thats HDMI to spliter to KVM) and even automatically sets that resolution, but doesn't display a picture. On a whim, I hooked the system up to the splitter powering the working system(the one I am typing this message on) and low and behold it worked famously.

So that seems to be the solution: better splitter.

For posterity sake(and anyone finding this thread in the future) the device that solved the problem is this:

J-Tech Digital Scaler/Multi-Resolution Output (MRO) 18GBps 1x4 HDMI 2.0 Splitter HDR10/Dolby Vision 4K@60Hz 4:4:4 [JTECH-18GSP14M]

https://smile.amazon.com/gp/product/B07F7LYFXQ/ref=ppx_yo_dt_b_search_asin_title?ie=UTF8&psc=1

What it actually does, for the curious, is let downscale a 4k display so it fits on a 2k monitor. I've been using it for years on the other PC to clone the screen, guess I can do the same with my main workstation now.

If anyone's interested I'm happy to post my weird setup. Just be forwarned: this way only madness lies.