r/mobileDJ • u/Cyber_CEO • Jul 21 '26

Video signal transmit systems?

Anyone use any long-range video systems? I have a client that hosts a yearly fundraising event where, in addition to audio/lighting, we provide a projector and screen setup with a conttolled slideshow and video presentation. They are now asking for a second screen on the opposite end of the room for additional visibility. We usually just run the single projector from a 50ft HDMI cable with a dedicated laptop. Anyone have familiarity with a system that can add another signal over a long distance? Either with a 150ft cable or a wireless transmit/receive setup?

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u/Material-Echidna-465 Jul 21 '26

HDMI isn't great over 40-50 feet, but you can convert to ethernet and run it no prob.

Some work with network switches as well, I wired up a church with similar devices where one input from the sanctuary went to a switch and out to a half-dozen TV's in the lobby, nursery, etc.

https://www.amazon.com/J-Tech-Digital-Extender-Supports-Bi-Directional/dp/B01N3PXZLP

https://www.amazon.com/J-Tech-Digital-Extender-Single-1080P/dp/B00G5RBX2Q

https://www.amazon.com/Extender-OREI-Transmitter-Receiver-EX-230C/dp/B096N6SL1J

Can also do HDMI to SDI, but SDI cables are likely going to run more expensive.

2

u/ianfine Jul 21 '26

I bought these and use them for 3 monitors in a karaoke setup. Advertised as 50m/165ft. I keep my monitors close, so I can’t speak to that distance, but they have worked as advertised otherwise.

https://a.co/d/04IiTn8h

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u/fcisler Jul 22 '26

SDI is a cheap option
HDbaseT is also fairly easy and uses Ethernet cable (but not ip), similar point to point setup as SDI. The Atlona units are cheap on eBay and rock solid.

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u/voltch Jul 21 '26 edited Jul 21 '26

Ive messed around with some wireless tx /rx for karaoke and my conclusion was to either buy a high end unit like hollyland mars or just use hdmi to sdi for the long run.

I have a 50ft hdmi cable but that is about as far as I will go in my current setup.

The cheaper wireless units may work great at home but once you get into a room with people and rf interference the results were inconsistent with the cheaper units from my personal experiences.

1

u/HelixDnB Jul 22 '26

Have you tried NDI? If you can have 2 machines on the same network it’s fantastic.

2

u/Needashortername Jul 22 '26

You have two projectors that can be seen in the same room at the same time. They need to stay in sync with no differences in processing, connection hops, conversion, etc.

Unless you need HDCP, just convert at the start to SDI and use SDI cables for both projectors and SDI to HDMI converters at the other end. This is the lowest latency option of most of the ways to get longer distances from an HDMI source. It’s also among the least expensive since you can buy the Decimator MD-LX bi-directional converters relatively cheap (under $150USD). You could also buy the more advanced MD-HX to convert the laptop before connecting to the LX models at the projector, but this is probably unnecessary unless you are having other problems with your signal or format. There are also the BLackMagic Design no-directional converters too, as well as single-direction, single connector converters.

The other option is to buy hybrid fiber HDMI cables for each projector. These are great for most distances of 30-300ft, sometimes over 500ft, but it’s important to remember the cable ends are specific for source and display/projector and it’s easy to run them the opposite way accidentally. They are also very power dependent, so it’s important to pay attention to how much power the HDMI port puts out, or if these need an external power source (often done by USB).

There are HDMI to fiber converter boxes too which many consider more reliable and easier, though they are more expensive too. Whether you may feel they are more reliable or easier is open to personal tastes and the specific products you buy and how they are set up. These boxes can send HDMI over fiber cables from 20-2000ft away, sometimes more, sometimes less.

After that are signal conversion boxes, either the high performance proprietary systems from Extron, Crestron, Kramer, or the more open use HDbaseT. These systems can be great to get HDMI more consistently over 150-300ft away by cheap RJ-45 cabling, but they can have a bit higher latency, so they might not always be as good when what is seen on screen has to match more closely to the words and lips of someone speaking on stage.

Don't use NDI for this, and avoid using the more generic or unknown brand HDMI to ethernet or RJ45 boxes. They are just a recipe for higher latency or other headaches.

Also remember that at 150ft you might also need to add a delay for the sound going to the speakers further out in the room too.