30m DVI cable

[Stuart91]

Looking for a 30m DVI cable for a customer - so far the only affordable ones I can find will only go up to 20m. After having a bit of a google around I've found some that cover longer distances but they actually convert the signal to fibre and are fearsomely expensive.

 

Does anyone know of a source for non-fibre 30m cables? Or is there some inherent limitation that means it's not possible?

[David Duffy]

Does anyone know of a source for non-fibre 30m cables? Or is there some inherent limitation that means it's not possible?

You can get DVI repeaters that are good for 20 metres I think. ie. Put one in between two 15 metre cables.

[Stuart91]

You can get DVI repeaters that are good for 20 metres I think. ie. Put one in between two 15 metre cables.

 

Thanks for the tip - however I fear that might not work in this instance because the 15m mark will likely be halfway up a wall... :D

[Cormac]

http://www.extron.com/product/product.aspx...amp;subtype=185

 

DVi extenders using cat5 twisted pair.

I would not expect this to be very cheap.

Other products such as DVi extenders also within the extron site.

 

C

[lukemh]

such things do exist in high quality but they use fibre, which has its own personality and fraility. - but it does allow a fantastic image if installed correctly over distances of up to 100m.

[Stuart91]

such things do exist in high quality but they use fibre, which has its own personality and fraility.

 

There's a chance if a 30m copper solution doesn't exist the customers will plump for fibre. I expect it will be more fragile than copper, but how useful is it for a typical installation? What kind of radius can it bend in? Would it get down a Unicol column without breaking at the end?

[TomLyall]

Fibre for 30m? I think that's going to be a little expensive for what I does.

 

VGA is normally fine over 30m, is there any reason why DVI wouldn't be okay? I'd suggest trying with just copper, join two shorter cables back to back with a gender bender, or find male to female versions.

 

such things do exist in high quality but they use fibre, which has its own personality and fraility. - but it does allow a fantastic image if installed correctly over distances of up to 100m.

Fibre solutions should be good for distances much more than 100m!

[lukemh]

Fibre for 30m? I think that's going to be a little expensive for what I does.

 

VGA is normally fine over 30m, is there any reason why DVI wouldn't be okay? I'd suggest trying with just copper, join two shorter cables back to back with a gender bender, or find male to female versions.

 

such things do exist in high quality but they use fibre, which has its own personality and fraility. - but it does allow a fantastic image if installed correctly over distances of up to 100m.

Fibre solutions should be good for distances much more than 100m!

 

Sorry I should have said the single cable premoulded options that we use are up to 100m but of course they are not limited to that.

 

if cost is an issue I suggest going HDSDI over copper

[Pete McCrea]

There was one company exhibiting a long DVI cable at Integrated Systems Europe- I think it got to about 50m or so, but was about the size of 63A mains cable.

 

There are two approaches to solving the distance issue:

1)Using CAT5 and splitting the image into the signal and control portions generally using 2 sets of CAT5

2)Using Fibre optic cables

Both tend to have a TX and RX unit for each end, some being no bigger than a large DVI connector backshell, others being a third rack width or there about.

 

Extron do a DVI over 2 sets of CAT5 cables, the DVI 201 which has an MSRP of £480 ex VAT. There are other options from several other companies using simillar technology. Unfortunately I can't remember the name of the other manufacturers.

 

Kramer do a DVI over Fibre Optic premade cable as do others. The cable is about 10mm diameter and will bend round radius of about 150mm. This basically builds a copper to fibre adaptor into the TX and RX into the connector shell. Extron do a the 'FOX500' or Fibre Optic eXtender that basically uses fibre to connect the TX and RX. The MSRP on these is £3056 ex VAT, so not cheap. I'd give you prices on the Kramer units but I don't have an electronic copy of the pricing.

 

The reason DVI generally doesn't go too well over longer cable is the losses in the cable. As it's digital, once the signal falls below the thresholds it fails to register and the receiver cant interpret the signal, so goes blank, unlike analogue where you just get smearing or a weak image. IIRC DVI is officially only meant to get to around 5m....

 

Obviously there are other manufacturers and resellers available. Hope that helps

[David Duffy]

You can get DVI repeaters that are good for 20 metres I think. ie. Put one in between two 15 metre cables.

Thanks for the tip - however I fear that might not work in this instance because the 15m mark will likely be halfway up a wall... :D

You can get 25 metre "special" low loss cables. (I sell them but no use as you're not in Oz)

Any chance you can shave 5 metres off the required run?

Adding shorter cables together to get really long lengths will result in "sparkles" in the picture I'm told.

The "special" longer cables are a low capacitance variety I believe.

[rubber duck]

AnalogWay have recently released a selection of DVI cables these range from 1.8m through to 70m with longer to be released in the near future.

 

http://www.analogway.com/products/product.php?Product=52

 

This can be powered or unpowered dependent how you are using it.

 

If you require any further information on these cables please email me at andrewr@true-colours.net

 

Andrew

[RichardM]

Looking for a 30m DVI cable for a customer - so far the only affordable ones I can find will only go up to 20m. After having a bit of a google around I've found some that cover longer distances but they actually convert the signal to fibre and are fearsomely expensive.

 

Does anyone know of a source for non-fibre 30m cables? Or is there some inherent limitation that means it's not possible?

 

 

Is it definitely a digital signal you're sending? If it were analogue you could get away with a 30m VGA cable with adapters (about 8 quid each) on either end...

r

[SeanT]

Or just convert the digital to VGA one or both ends, still be cheaper than the senders!

[Solstace]

Okay - so such silly lengths are available - fantastic!

 

So: I'm about to design a system that throws full 1080p HD content around a building, distributing to 7 screens in the main venue and several screens in other rooms around it. At present the plan is to run the signals DVI-fibre lines around the building.

 

Now if I were to read this thread (and some other info linked from it) in ignorance I could come to the conclusion that sending such resolutions down 30m+ copper cable lengths ought to be possible - which unfortunately completely contradicts the advice received so far.

 

Has anyone done this? Does it work in "real-time" at full 1080p without sparklies, latency, recompression (using motion JPEG or similar) or other artefacts? Can it be reliably redistributed after such a long run? Can I go anywhere in or around London to see this in operation?

 

Sorry - so many questions, but I'm just wanting to cut through the noise! Apologies if this strays into a new topic!

[Stegga]

the best bet might be buying a cable of the correct length - 'Ebay 30m VGA cable' - and try it out. I have run a 30m length without trouble before