VGA & Video relay

[richard_cooper]

I have an upcoming event in one of my venues that needs to be relayed into another building. I need to send a video feed of the speakers to one screen and a copy of their powerpoint presentation for another screen. I have the cameras/vision mixer and audio side already that will not be a problem. My concern is how to send the video down approx 150-200m of cable and how best to do the same with the VGA output from the computer. Quality needs to be as good as possible. I've never really been that involved with the video side of things and could do with some advise.

 

Does anyone have any pointers with this, or any pointers to good books on this sort of area.

[Andrew C]

You can get "media convertors" (not sure correct name) that will do just what you need. They are hireable from A/V presentation type outfits. I've only done this once, so I'm not up on detail.

[bruce]

What sort of links do you have between the 2 buildings?

 

Co-ax? Fibre? Balanced audio? Nothing?

 

Is there a data network in place between the 2 buildings?

 

 

I've done several events like this,over distances from 50m to 100 miles - but typically about 1km. We did it in several different ways, depending on what infrastructure was in the ground....

 

For the powerpoint display, by far the best option, assuming there is a data link in place, is to use a PC at each end, and some sort of application-sharing software. Microsoft netmeeting is ideal, and free. It will probably already be installed on both PCs, fire it up, share the application, and then anything which is displayed on the "master" machine will be mirrored on the "slave". But if you've never used this befoire, test it first.

 

For audio & video, there are many options. I have used:

 

Long cables - up to 1km in one case! Need DAs with plenty of gain, and proper tools to tweak them.

 

Analogue video/audio, FM encoded and transmitted over fibre.Typically gives slightly better than VHS-type quality. Hardware is relatively unusual, but available via the CCTV surveillance market. Simple. We've done lots of this, for lecture overspills etc. The encoder/decoder units are about 1k/pair, if I remember correctly.

 

Audio & video, H.323 encoded and transmitted over a data network, using video-conference hardware. Expensive, but works well if you have a decent network connection between the sites. The same hardware may also be able to transmit your powerpoint simultaneously.

 

Another option that I've looked at is using a dedicated MPEG4 hardware codec. These units can provide 4CIF quality, over about a 2Mb/s data link. Display is either via a similar hardware unit, or on a PC. I'm hoping to get a pair of these on evaluation very soon. They're becoming common in the CCTV arena.

 

Bruce.

[colinmonk]

You could also just rent a couple of TCP/IP Video Transmitters/Receivers, and send the data across Cat5...

 

Split the powerpoint machines VGA out with a 2way DA, then feed one down one cat5, then send a composite feed off a camera down the second cat5

 

You could just buy a box or two of install Cat5 ( as its cheap as chips, it wouldnt really matter if you binned it at the end )

[bruce]

One other thing - if you are running copper between 2 buildings, be very very careful about grounding and isolation. There can easily be a substantial voltage between the "earth" levels. So you need to take great care, particularly with screened cables.

 

Bruce.

[computer]

KAT5, although aimed at domestic use may be able to help you. the guy also has a vga version 99% working atm you could ask him about.

[Pete McCrea]

I'd go down the route of using the CAT5 Sender units. Stick the VGA in, CAT5 out the other side. Then upto 500' of CAT5 to the RX.

 

Extron do units with the ability to send Audio too. If you could mix the video feed into a scaler/mixer then output on VGA, you'd need the one CAT5 link to send the Audio and VGA signal

[colinmonk]

Extron TCP/IP products are very good! Excellent quality, and highly reccomended, If you need any help tracking down a rental company for any then can offer one or two names...

[Peter F]

Cat5 cable is your friend.

 

Do a google for Intelix baluns, they'll do the job. Other companies make similar products. Most decent AV hire companies will have some in stock, Canford Audio sell them.

 

If you can convert the vga signal to a composite one at source you will be able to do it all (i.e. both directions) with one cat5 cable.

 

If you had an intelix V2A2 at each end you could send audio between the 2 locations as well.

 

Standard cat5 cable will do the job fine.

 

It really is a jolly fine solution to yours and many other problems.

 

All the best,

 

Peter

[bruce]

I've used CAT5 baluns too - they're surprisingly good. You may well need DAs with variable outputs.

 

I even once used them to drive audio and video over a length of ancient BT phone line which was the only link we had between 2 buildings. It worked!

 

So, it all depends what sort of cables you've got between the locations.

 

And as I said before, be careful with the grounding.

 

Bruce.

[IanG]

approx 150-200m of cable

<{POST_SNAPBACK}>

 

For the video this kind of distance is easily doable with standard cable.

 

Look in Canford for PSF1/2 (28p/metre at the moment), PSF1/3 and SDV-L cable.

[bruce]

Many of the suggested solutions involve running new cables between the 2 venues. Is this practical? No intevening roads etc?

 

Bruce.

[slim_mcslim]

CAT5 is my prefferred method of distribution - the cheap baluns type devices are only really good for about 50m, we have powered boxes that do it and are excellent, howver the audio that comes out at the other end is shockingly bad, so either run a long XLR or use another cat 5 and an audio only converter.

 

paul