# Low Cost, VGA Splitters and VGA over CAT5 Baluns



## memoguy (Sep 29, 2014)

Hi there, I am looking for some recommendations around VGA Splitters and Cat5 Baluns. Both of these devices will be operating at 1024*768, 60hz. The Baluns need to get the VGA across a run of about 75 meters.

The budget is basically as low as possible as this is going to be used in a High School.

I am currently looking at these:
http://www.jaycar.com.au/productView.asp?ID=AC1671
http://www.jaycar.com.au/productView.asp?ID=YN8075

I will need two splitters and two sets of baluns.

Also does anyone know what the actual difference is between a powered VGA splitter and a simple VGA Y cable like this:
http://www.belkin.com/images/product/A3G006-01/372.jpg

Interested to hear your thoughts on all of the above


----------



## Chris15 (Sep 29, 2014)

What cable are you using Cat5? Cat5e? Cat6? Cat6A? Belden Nanoskew or equivalent?
That's the first step into understanding whether the solution will work.

In general, anyone using a Y cable on video ought be shot.
They wreak havoc with the impedance of the transmission lines, and you're dealing with high enough frequency signals for that to be a problem...


----------



## peterleif (Sep 29, 2014)

one thing we use in my job is called magenta boxes. they go from VGA to Cat5 from a transmitter to a receiver. I cant talk on price though. We've used them for well over 200 ft runs. you could also look at a Distributor Amplifier for the multiple vga runs, though magenta does have a DA splitter for cat5 runs. But if your looking at multiple inputs youd need a switcher.


----------



## memoguy (Sep 30, 2014)

Thanks for that! Is there any chance you could link me to the box you are talking about?

I am not too sure what the cabling is. The cable is already in the wall just with rj45 patch points on each end. I am guessing it is cat5 or better


----------



## Chris15 (Sep 30, 2014)

See the thing is that as you get "better" than Cat5, for analog video, your performance gets worse, especially at distances of 75m.
The very improvements that make for better data performance, ie. different skew rates for each of the pairs, make it painful for analog video.

You've got access to both ends of the cable? Remember that having a network switch in the way is the surest way to have nothing work.

In the end, you get what you pay for.
75 metres is not a trivial run by anyon'e definition. Skew is likely to be a problem with anything except the nanoskew type cables. These baluns allegedly have skew correction, so playing with them may produce acceptable results.

If this is for permanent installation, consider seriously whether investing in VGA infrastructure is a wise use of money - VGA is dying quickly, HDMi is the current way forward, for how long, none of us really know...


----------



## memoguy (Sep 30, 2014)

Yeah, I have access to both ends of the cable. This cabling is not installed for network access so there is no switch, this is just for theatrical data applications. Out theater is wired everywhere with RJ45 for data, BNC for video, XLR3 for audio and XLR5 for lx. 

Right now VGA will have to be the go, as all the gear we have uses VGA. The intention here is to use this to run two projectors with edge blending. The system will consist of this:

Mac running Qlab
analogue dualhead2go
2X VGA splitter
2X VGA bulan pairs
2X projectors
3X 4:3 monitors

Setup in an arrangement like this:
https://dl.dropboxusercontent.com/u/51681259/diag.png

I think it is important to split the VGA signal out like this and feed it to monitors to allow for easy troubleshooting. (i.e. if something goes wrong we can blank the projectors and fix it on the booth monitors before unblanking the projectors)


----------



## Bubby4j (Sep 30, 2014)

I just recently did a upgrade in my church with VGA, much like you're wanting to do.

I agree that if possible I'd use DVI/HDMI, but that is getting pretty expensive. Especially if you need a video switcher also.

I bought a bunch of Extron baluns off ebay. Then I got a bunch of power supplies for them and other assorted things. It came out to around $140 per "channel" (sending video to 6 displays at the same time, each one with its own run), including an Extron IN1508 switcher. It's not true seamless, but it's good enough for my use.

I found these extron whitepapers very interesting, it explains skew and other effects which can degrade the video quality. That's why cat5 is better than cat6, and skew free cable is better than cat5.

https://www.extron.com/download/files/whitepaper/tp_intro_wp.pdf
https://www.extron.com/download/files/whitepaper/tp_opt_wp.pdf


----------



## StradivariusBone (Sep 30, 2014)

Chris15 said:


> If this is for permanent installation, consider seriously whether investing in VGA infrastructure is a wise use of money - VGA is dying quickly, HDMi is the current way forward, for how long, none of us really know...



Is there a reason why DisplayPort hasn't taken the place? I know Apple has adopted it into their ThunderBolt design and I've heard many laptops are now sporting DP out. It's very easy to convert to VGA as well. HDMI with its variants seems like more of a PITA to me. Plus DisplayPort is royalty-free.


----------



## kevlar557 (Sep 30, 2014)

StradivariusBone said:


> Is there a reason why DisplayPort hasn't taken the place? I know Apple has adopted it into their ThunderBolt design and I've heard many laptops are now sporting DP out. It's very easy to convert to VGA as well. HDMI with its variants seems like more of a PITA to me. Plus DisplayPort is royalty-free.



Not only that, but its a LOCKING CONNECTOR!!!!!! Imagine that haha. DisplayPort is superior in just about every regard: Higher resolutions, multiple audio/video streams, etc... Only problem is that its a classic case of Betamax vs VHS. All of the manufacturers and content producers backed HDMI.

Now off of that rant - Look at Monoprice's VGA extenders. Surprisingly, I've used them without too much hassle, and they're cheap as chips. Link below:

http://www.monoprice.com/Product?c_id=101&cp_id=10105&cs_id=1010504&p_id=5034&seq=1&format=2


----------



## Bubby4j (Sep 30, 2014)

kevlar557 said:


> Not only that, but its a LOCKING CONNECTOR!!!!!! Imagine that haha. DisplayPort is superior in just about every regard: Higher resolutions, multiple audio/video streams, etc... Only problem is that its a classic case of Betamax vs VHS. All of the manufacturers and content producers backed HDMI.
> 
> Now off of that rant - Look at Monoprice's VGA extenders. Surprisingly, I've used them without too much hassle, and they're cheap as chips. Link below:
> 
> http://www.monoprice.com/Product?c_id=101&cp_id=10105&cs_id=1010504&p_id=5034&seq=1&format=2



Although, it doesn't look like they have skew correction or peaking adjustment.


----------



## kevlar557 (Sep 30, 2014)

Bubby4j said:


> Although, it doesn't look like they have skew correction or peaking adjustment.


 
That is the one thing I don't like about them, but you get what you pay for I suppose. I haven't had a situation where it was needed, but I always use STP when putting in extenders. 

If you feel like you'll need adjustments like that, there are tons of Extron MTP systems for sale on eBay. The Magenta boxes that were mentioned earlier are OK, although with their HDMI boxes, we previously had a lot of DOA devices.


----------



## StradivariusBone (Sep 30, 2014)

Probably about 95% of the machines I see in the building when we rent out to presentations/meetings have VGA, but the only other thing I've been asked to plug in is mini DisplayPort on the Macs. What's the signal drop off like compared to HDMI? I know there are issues running SDI and HDMI over long runs, hence this discussion about baluns. 

At my church, we use a setup that turns DP into VGA and then splits it into RGBHV and that run is about 200' running off a TripleHead2Go alone. It shouldn't work, but somehow it does. Before that it was just VGA to RGBHV through a splitter/amplifier.


----------



## Chris15 (Oct 1, 2014)

DP uses lower voltages than HDMI, so on one hand, I would expect it to drop off quicker through resistance, on the other hand, lower voltage means less of a voltage swing, which may have favourable implications in the frequency domain.
In terms of real world - I honestly haven't read enough or used it enough to know what distances are viable.

At the moment, DP better supports higher resolutions than 1920x1080 in terms of adopted implementations. HDMI 2.0 handles 4K fine though.

One of the reasons HDMI will continue to dominate in the consumer AV sector is CEC, all the TV companies like to boast about their implementations - VieraLink, AnyNet Control, etc.
While DP can handle that through the Aux data channel, it has not been standardised in the way that HDMI has been.

As for DP being locking - is that actually helpful in the consumer market where people are used to non locking connectors?
RCA, minijack, HDMI, SVHS, and friends are all non locking connectors, and so to throw a connector that looks similar but locks is likely to confuse Mrs Smith when trying to connect her new Bluray or more particularly when disconnecting it to replace a broken one, move the furniture, whatever...

SDI generally is happy with relatively longer distances, part of it's heritage as a broadcast standard when long (hundreds of metres) is part of the deal. But the original SDI was only SD, so along came HD-SDI, using 2 links, and then 3G-SDI came along to go back to one cable and 1080p resolution.

Oh, and just as a side note, the TMDS streams in DVI, HDMI and DP are fairly similar, and depending on the equipment being used, can in many cases be plugged directly into one another by passive cable adapters...


----------



## KeepOnTruckin (Oct 1, 2014)

You said you have BNC for video. Do you have 5 BNC connectors at both ends? This would seem to indicate you could use a VGA-to-RGBHV adapter at both ends if your BNC connectors are in useful locations.


----------



## memoguy (Oct 2, 2014)

Unfortunately there is not quite that much BNC in the roof. Maybe 2 patch points in the vicinity of each projector


----------



## peterleif (Oct 4, 2014)

hey sorry i havent gotten back sooner, the boxes i was referring to are these http://www.markertek.com/product/mg...iew-ii-xrtx-a-video-and-audio-utp-transmitter, they aren't cheap sadly.


----------

