VGA over Cat5

[Bazz339]

VGA over CAT 5

 

Am I right in thinking there are 2 ways.

 

1 using baluns boxes ? Passive?

 

2 using senders and receivers? Active?

 

I need to get video to a projector (not a problem that could be via a VGA cable) and a monitor.

 

The monitor concerns me. The best routes for cables take the signal near or very near the induction loop cable which for a VGA cable will almost certainly cause interference, Given the twisted nature of Cat5 cable does anyone know if it will using passive baluns boxes. My feeling is the best bet is probably to use active TX and RX boxes over cat 5 (Screened in both instances) obviously trying to keep as much distance as possible from the loop cable but that may not be much.

 

Presumably if I use an (Active) transmitter from one company I have to use its receiver or is there a standard enabling a receiver from a different company to be used?

 

Referring to my other recent post is there a switcher scaler that will take in VGA X 2 Video times 1 and output via 2 X CAT 5 with a local monitor output on VGA?

[headoned]

In the past iv always used these

http://www.kvmswitchdirect.co.uk/acatalog/Cat_5_6_VGA_Extenders_Distribution.html#aCatXQVideoRx

The mini av tx and rx. They have always been a solid option when doing installs plus you can get a USB power cable that will run the transmitter if your running from a PC or computer of some sort

.

VGA over CAT 5

 

Am I right in thinking there are 2 ways.

 

1 using baluns boxes ? Passive?

 

2 using senders and receivers? Active?

 

I need to get video to a projector (not a problem that could be via a VGA cable) and a monitor.

 

The monitor concerns me. The best routes for cables take the signal near or very near the induction loop cable which for a VGA cable will almost certainly cause interference, Given the twisted nature of Cat5 cable does anyone know if it will using passive baluns boxes. My feeling is the best bet is probably to use active TX and RX boxes over cat 5 (Screened in both instances) obviously trying to keep as much distance as possible from the loop cable but that may not be much.

 

Presumably if I use an (Active) transmitter from one company I have to use its receiver or is there a standard enabling a receiver from a different company to be used?

 

Referring to my other recent post is there a switcher scaler that will take in VGA X 2 Video times 1 and output via 2 X CAT 5 with a local monitor output on VGA?

[handyandi]

Had exactly this problem & had the cheap (£50) balluns from CPC but was better than plain vga but still showed loop interference. Upgraded to Kramer Active units (have a 1:4 out - for future expansion)& has been rock solid ever since. A bit pricey but very well made units. They recommend using FTP cat 5 but have no problems with UTP. Loop is parallel for 10+mtrs within 6". Can let you know which units if you want.

[Andrew Edwards]

Canford stock a selection of items from Databay. The work over any low skew cat cable (Unscreened Twisted Pair). It would appear that the main difference between all the various levels of kit is the max distance that can be achieved at differing resolutions.

 

£120+VAT for up to 180m at 2048 x 1536 for their miniature version. They appear to require a transformer at one end which also has a video EQ and the other end is USB powered. I've seen similar items for not much less and they can barely muster 60m at much lower resolutions usually due to only being active at the transmitter or completely passive.

 

I'm currently looking to source a replacement for an impossibly long VGA cable that recently failed and will probably go for the Databay miniature. I will report back when I get it.

[Bazz339]

20M tops distance wise.

 

I thought active would probably be better for rejecting interference.

 

Sorry not at the top of the tree with data cable FTP and UTP? presumably different standards of cable?

 

Do TX and RX have to be from same manufacturer or will they (or at least some talk to each other)?

 

Thank you for the replies and suggestions, keep them coming.

[Shez]

Sorry not at the top of the tree with data cable FTP and UTP? presumably different standards of cable?

FTP - Foil (screened) Twisted Pair.

UTP - Unshielded Twisted Pair.

[AHYoung]

Canford are having a laugh if they claim that you will get 2048 x 1536 180m down a bit of cat 5 cable using cheap baluns... ive experience of a few of these products and to my mind there is big difference between working and acceptable quality. Most of the cheap units crap out at anything beyond Xga@ 60hz let alone 4 times that... The kramer and extron units generally work but they cost a bit more. Im not sure why you would buy a transmitter and reciever from different manufacturers , and id doubt that poducts are compatible. There is a standard for video transmission via Hd base T technology which means that different devices are/should be compatible but thats a slightly different thing- more expensive again, but possible a better future choice for future compatibility.

 

 

With VGA the way these things work is by multiplexing 5+ analogue signals , rgbhv plus stereo audio, rs232 etc and sending it down the different lines . on standard network cable its very deliberately made with precise and different wind ratios on each core, this is ideal for data transmission, but the rgb video end up skewed as the different colours get delayed by different amounts by the differing cable lengths of the pairs, Video is such a high frequency that its pretty obvious. Better baluns offer better inbuilt compensation, but there is a limit and thats where the low skew cable comes in - this looks like normal cable but each pair has the same number of twists. Not good for networking but better for AV. When you get into Digital video transmission over cat 5 you need a totally different special cable as the skew doesnt matter, but the shielding and bandwith does.

 

 

Also if the main reason for doing this is to avoid the interference from the loop, youd be better at looking at a fibre based solution as by its nature its immune, its more expensive on paper, but once you start looking at the special cable you need for the cat5 systems, its gets very close in price if not cheaper.

[Bazz339]

Im not sure why you would buy a transmitter and reciever from different manufacturers ,

 

 

I would not through choice, I just wanted to know if there was a common standard for TX and RX.

 

With VGA the way these things work is by multiplexing 5+ analogue signals , rgbhv plus stereo audio, rs232 etc and sending it down the different lines . on standard network cable its very deliberately made with precise and different wind ratios on each core, this is ideal for data transmission, but the rgb video end up skewed as the different colours get delayed by different amounts by the differing cable lengths of the pairs, Video is such a high frequency that its pretty obvious. Better baluns offer better inbuilt compensation, but there is a limit and thats where the low skew cable comes in - this looks like normal cable but each pair has the same number of twists. Not good for networking but better for AV. When you get into Digital video transmission over cat 5 you need a totally different special cable as the skew doesnt matter, but the shielding and bandwith does.

 

Thank you for the detailed info.

 

Also if the main reason for doing this is to avoid the interference from the loop, youd be better at looking at a fibre based solution as by its nature its immune, its more expensive on paper, but once you start looking at the special cable you need for the cat5 systems, its gets very close in price if not cheaper.

 

 

Hadn't thought of that. A quick perusal off the net suggests TXs and RXs many hundreds of pounds, is that the case or are there cheaper? Also I have no tools for terminating with fibre optic cable.

[AHYoung]

You can simply buy the fibres premade , they are pretty common these days in data networking and its cost equivelent to anything more than bog standard Cat 5, the Rx / Tx part isnt any more than decent high bandwith cable baluns either so if the intention is to avoid interference and additionally completely isolate it from any ground loops, its a better option, as your cat X stuff may or may nott work wheras your fibre definitely will, and even in a cost driven situation, cheapest isnt best if its not guarenteed to work...

[Bazz339]

I have not been able to find any VGA to fibre to VGA RX and TX units at price that the budget could accommodate reasonably and I do think they probably provide the most sure fire way of eliminating the problem.

 

What price do they start from and who stocks them please?

[AHYoung]

if you want the most cost effective solution, you would be better looking at dvi rather than vga over fibre, kramer 621t / 621r list at 199 each, but you would expect to pay less - we sell kramer, but so does everyone including CPC. fibre available from CPC etc or off the shelf from your nearest networking wholesalers.

[Jippus]

In my experience Kramer is the way forward. I have used their kit on a few installs and they pretty much do what they say they will. I'd stay away from cheaper products, they are not so good in my experience. I have called Kramers tech guys in the past to talk through problems and they are very very helpful.