What do you do to connect HDMI Devices in "long distance"? - Page 1
Forum section: electronics / general

author: Zucca
author_rank: Unknown
timestamp: April 15, 2019, 02:37:34 pm
content: short story:This weekend I had to set up a satellite receiver + projector in a room for >200 people. The sat receiver and the projector were about 12meter far away from each other.I did some tests with a 15meter HDMI cable and no issue at all. Once I arrived at the place the "expert" tech guy there strongly suggested to use those :https://atlona.com/product/at-uhd-ex-70-kit/because an HDMI connection >12meter is unstable. He would provide the LAN network and the device for free for us.Everything was working great until I lost the HDMI link in the middle of the show, and the 200 people were looking at me....Back to regular cable I had no issue at all.What do you do in case of long HDMI connections?Now I did some homeworks, is it true that above 50 feet/15meter it become unstable?PS: Once I told him, the expert guy were kind of speechless and red in face.

author: soldar
author_rank: Super Contributor
timestamp: April 15, 2019, 03:05:04 pm
content: If you test it with the HDMI cable and it works then I see no reason for complicating things further. But I mean testing the actual parts involved, not just some other parts. My experience is that things which are supposed together in theory often do not work together in practice.One cable works with one phone but not with another in spite that they are supposed to be exactly alike. etc.If the setup works then leave it as it is.

author: ogden
author_rank: Super Contributor
timestamp: April 15, 2019, 03:09:13 pm
content: Quote from: zucca on April 15, 2019, 02:37:34 pmI bring satellite receiver next to projectorMain problem with "longer than usual" any cable is - devices differ, cables differ as well. If you can get best of everything - TX, RX devices, cable and no interference sources around then you may run HDMI over low loss cable for long runs, including 15m. For example my previous (2015yr) laptop had "weak" HDMI output. In many meeting rooms where projector is ceiling-mounted, it often had HDMI signal issues while colleagues happily used projector.If I recall it right, common assumption of max HDMI cable length is 5m. There are extenders over Cat6e cable with amplifiers inside and then there are extenders that encapsulates HDMI into Ethernet frames to send over Ethernet. You just have to get hardware and cables youcantcan trust, test everything twice before critical shows

author: soldar
author_rank: Super Contributor
timestamp: April 15, 2019, 03:33:44 pm
content: Quote from: ogden on April 15, 2019, 03:09:13 pmThis is the critical piece of advice. Test extensively, test again. That is how you minimize your chances of running into problems.

author: Zucca
author_rank: Unknown
timestamp: April 15, 2019, 08:27:14 pm
content: Quote from: soldar on April 15, 2019, 03:33:44 pmWell I did, and if next time a "professional" expert tells me it is better the other way I tell him:"No, thank you".I bet you I will still run into problems because Murphy always win.Quote from: ogden on April 15, 2019, 03:09:13 pmI will not touch an HDMI to ethernet frames anymore. This because the network capacity should be able to handle it. Who knows if the router,switch or what else will play bad here.Extenders over a dedicated CAT6e look more sexy.https://www.startech.com/AV/Extenders/HDMI/hdmi-cat6-extender~ST121HDBT20SWhat do you use?

author: ogden
author_rank: Super Contributor
timestamp: April 15, 2019, 09:03:10 pm
content: Quote from: zucca on April 15, 2019, 08:27:14 pmIf you do not want to challenge Murphy's law - do not challenge specification of the product.QuoteYou shall know. Obviously. If you can't - it is your problem, not problem of the converter you use.

author: lamabrew
author_rank: Regular Contributor
timestamp: April 15, 2019, 09:12:44 pm
content: There are so many unknowns in a question like this. If the video is 1080p 60Hz (i.e. what fit in the original HDMI 1.2 bandwidth equivalent of 165 MHz pixel rate) then you can probably go 15m or farther with high quality cable. If the video is 4K resolution and/or more than 8 bit RGB (or 12 bit YUV), i.e. 225 MHz to 340 MHz equivalent rate, then 5m might be it. The newer HDMI 2.x 600 MHz equivalent might not even make it that far.HDBaseT is a pretty reliable way to get < 300 MHz HDMI up to 70m. Not sure why the word LAN was added as HDBaseT is point to point connection that uses CAT 5/6 cable in a proprietary format, it is not a HDMI over Ethernet system.HDMI and particularly the HDCP Digital Restrictions Management (DRM) system that consumer gear has inflicted on it is very, very fragile. If the video resolution changes or blips the whole link (BY DESIGN!) comes crashing down and can take a few seconds to re-establish itself. I've seen plenty of devices that operate normally most of the time but get confused if the source blips at just the wrong time and/or a few times in a row quickly. The only cure is either a cable unplug/replug or in some cases power cycling one or both devices.The fact that putting the old cable back "fixed" it could just be coincidental, the whole sequence could easily have happened without changing cables and/or just using the direct HDMI connection.Gear from more than half-dozen years ago tends to have more problems than newer gear as the newer HDMI chips can be somewhat more reliable. But I've yet to see any HDMI chip (among the 4 vendors I'm familiar with) that works perfectly 24/7/365 with all equipment combinations.But to answer the original question: HDBaseT (both ends from the same vendor) for 10m to 70m range and fiber beyond that. If needing more than a few point to point then HDMI to IP is probably the best bet - but you need dedicated switches, etc., you don't put that over your regular network. Or you go with broadcast (SDI) gear as that stuff is designed to work (but it's also big $).

author: Zucca
author_rank: Unknown
timestamp: April 15, 2019, 09:18:04 pm
content: Quote from: ogden on April 15, 2019, 09:03:10 pmYes the problem I trusted I guy who should have known his network.ogdendid you had good experience with HDMI to Ethernet Frames converter?If yes which one you used?

author: Zucca
author_rank: Unknown
timestamp: April 15, 2019, 09:20:26 pm
content: Quote from: lamabrew on April 15, 2019, 09:12:44 pmlamabrewthank you so much, that's the feedback I was looking for. Now I have to do some homeworks and digest that. Thanks again.

author: ogden
author_rank: Super Contributor
timestamp: April 15, 2019, 09:27:45 pm
content: Quote from: zucca on April 15, 2019, 09:18:04 pmI have no experience with such converters, yet I am sure that I would find one that works for me - if needed. In case I can't find one that works for me then most likely I can't find one or it simply does not exist. Part of my reply is sarcasm because it is becoming increasingly difficult to find best products using internet (search).

author: Lukas
author_rank: Frequent Contributor
timestamp: April 15, 2019, 10:19:53 pm
content: SDI/HDMI (and vice versa) adapters are $25 a piece on ebay and 75 Ohm coax cable shouldn't be that expensive either...

author: KC0PPH
author_rank: Unknown
timestamp: April 15, 2019, 10:37:11 pm
content: Once your HDMI cable gets to be long buy the one with the amp built into it.

author: donkey77
author_rank: Regular Contributor
timestamp: April 16, 2019, 06:27:51 am
content: I watched this a while back but haven't got around to using the info for my project yet.https://youtu.be/XFhx8Zy95IY

author: dmills
author_rank: Super Contributor
timestamp: April 18, 2019, 11:53:49 pm
content: SDI is a decent way to go, and if you know your gear there are converter boxes out there with a single thru hole resistor on the board amongst all the smt stuff, cut it and magic happens to the HDCP pain.SDI at 3G rates is picky about cable and connector performance if you want reliable operation, but it works very, very well out to over 100M with negligible latency.YellowBrix have good stuff, BMD have cheap and sometimes slightly flaky stuff.Regards, Dan.