Saturday 13 March 2021

Solving HDMI Long Run Dropout

My Sky TV box feeds three displays throughout the house; a JVC projector in the Home Theatre, a Panasonic 58DX800 in one living room and a Samsung 7 Series TV in another All are more or less 4k , (the JVC is a Faux-K unit), but all support UHD resolution, which the Sky box outputs.

I don't see much value in the additional multi-room subscription for Sky as we really don't use more than one TV at a time, and on the odd occasions we do, we can run the Sky app on a playstation or other device.

So the challenge is how to route the signal to each device. All are reasonably proximate to the Sky box with runs from 7M for the projector to 15M for the two TVs.

I have the system set up as follows;

 The SkyQ box feeds an HDMI Splitter via a single HDMI cable. This serves 2 key functions; It allows me route to the 3 devices, but also strips HDCP, without which my JVC won't display an image.

One splitter output has a run of 20M Fibre 4K cable direct to the Panasonic TV, while the other goes to the Marantz AV8805 Cab/Sat input, to connect to the JVC projector as needed (Zone 1) and permanently routed to the Samsung TV (Zone 2)

This mostly works, except that the HDMI connection to the Panasonic TV is unstable, (red arrow above).. From time to time there are merge visual artefacts (green lines), some audio drop-out and fairly frequent re-syncs where the screen blanks and resets, resulting in a 1-2 second interruption.

I'm on my second or maybe third cable and thought that this Fibre version would resolve the problem, but unfortunately not. I've also tried all sorts of configurations including testing direct cable connection between the SkyQ box and the TV, but the problem always exists. Some combination of this TV model and the cable run length is problematic.

Before considering purchase of an expensive 8K Fibre cable, I thought I'd try HDMI over ethernet as I had a spare AVAccess HDBaseT extender kit I'm not using. The configuration now looks like this;

And this works perfectly. The AVAccess devices are rated at 4K60Hz over 40M Cat5e, which is more than enough for my needs. Been watching UHD content all through the day without any hiccups so, problem solved!

I've written before about these devices for routing virtual computers, but they really are very flexible pieces of kit. If you're having trouble with lengthy HDMI runs, you could do worse than look at this solution.