HDMI cables

kleefarr

Is there any maximum length for an HDMI cable from sky box to TV before picture degrades?

John mac

25Meters

kleefarr

Great, thanks.
Need a 15/20 mtr one.
Only prob is, I have now realised that in laws only have a standard Sky box. :rolleyes:

brian_gall85

If at all possible it's much better just to run some more co ax cable and move the box.

kleefarr

Well that's the thing.
The box is in the kitchen. The picture on the TV in the kitchen is fine, but the picture on the TV in the front room is not great. I assumed that it was the quality of the cable, hence my thought about changing it to an HDMI cable.
The box though, even though they got it replaced about a year ago, is an old looking one to me and doesn't have the HDMI socket.
I was looking at some second hand HD boxes on some site. But do you think that changing the co axial cable might improve things?

brian_gall85

It can't really make thinks worse, but if I were you I would get a HD box, picture quality is so much better.

kleefarr

That's what I thought.
Have suggested it, so we'll have to wait and see.

John mac

if there is a hd tv in the front room move the new hd box there, run a coax to the tv in the kitchen.

a lot cheaper than buying a long hd cable.

kleefarr

A long HDMI cable is only €20/30 though.
Most of the time the Sky is viewed in the kitchen anyway, so moving back and forth to the front room to change channels would be a pain. And not going to the hassle of setting up a magic eye or anything.

mossym

John mac wrote: »

25Meters

the hdmi spec doesn't specify a maximum length, it specifies a minimum signal level that has to be available at the sink(normally display). get a poor enough cable and you could be below that level at 5m.

op, long cables are really hit and miss, be very careful what you buy, there's been lots of cheap long cables bought on ebay that end up in the dreaded sparklies or a complete loss of picture altogether,

at that length you would be better off looking at some hdmi to cat6 baluns and using cat5/6 cable to carry the signal

watty

HDMI *IS* same spec as Cat5e for the data / clock and doesn't need baluns. Cat5/6 won't let it go further. What you need is a repeater or line driver/receiver. Passive baluns / Cat6 won't go any further than real HDMI cable.

If going 3m to 14m with a "home made" cable (or ANY length with adapators) you need TWO runs of SCREENED Cat5e or Cat6
http://www.techtir.ie/howto/hdmi-via-cat5-cable


A maximum length of 15m is specified for the "Standard" weight HDMI cable which is electrically identical to screened Cat5e for the twisted pair parts. Longer needs much higher grade cable than Cat6 or repeater/drivers.

mossym

watty wrote: »

HDMI *IS* same spec as Cat5e for the data / clock and doesn't need baluns. Cat5/6 won't let it go further. What you need is a repeater or line driver/receiver. Passive baluns / Cat6 won't go any further than real HDMI cable.

If going 3m to 14m with a "home made" cable (or ANY length with adapators) you need TWO runs of SCREENED Cat5e or Cat6
http://www.techtir.ie/howto/hdmi-via-cat5-cable


A maximum length of 15m is specified for the "Standard" weight HDMI cable which is electrically identical to screened Cat5e for the twisted pair parts. Longer needs much higher grade cable than Cat6 or repeater/drivers.

any passive solution for hdmi extension that takes power from the 5v on the hdmi cable is a bad bad idea, the 55ma supply there is for one thing only, hot plug detect on the far end so passive units that use this for supply are a bad idea and should never be used. but agree with your point that they won't go any further. There is a bigger debate here about passive equalized cables, but that's a different matter

powered units with an external power supply can go further than HDMI cables, due to active equalization. also, they don't all need double runs of cat5 cable, solution here using a single cable for 50m length, have seen this in operation at a show and it works

http://ukhdmi.com/cablesson-hdmi-over-ethernet-single-cat56-extender_QQ101813

and any max length cable given is based on a certain gauge wire at a certain distance to deliver a passing eye diagram at the HDMI recevier, the HDMI spec doesn't quote max cable lengths, it's down to the signal level at the sink, you can work backwards and derive cable lengths, but they are not specificied, and any max cable lengths given are based on the HDMI spec, not a part of it. Have a look here

http://www.scribd.com/doc/48078495/43/Table-4-20-HDMI-Sink-Impedance-Characteristics-at-TP2

watty

I think we are saying the same thing differently, but agree.

The distance is implied by the recommended cable.
For more than 12m to 15m you need an active self powered solution or very expensive cable.
The built in Power isn't for powering anything.
True "Baluns" are purely passive "current choke" style transformers. They are pointless and do not extend the cable. They can be used with SCART or VGA without power and Cat5e. So called "balun" working solutions for HDMI extension are nothing of the sort. They are separately powered amplifiers and if they don't have a switch setting for distance are either rubbish or for a fixed distance or using fibre or putting the signals on a carrier.
Anything using a single Cat5e/Cat6 cable is definitely and active solution needing its own PSU.

mossym

watty wrote: »

I think we are saying the same thing differently, but agree.

yeah i think we are. think any further posts should be to help the OP with his problem..:)

and apologies to john mac for using the term absolute rubbish, no need for bluntness like that, a consequence of the last moments of my bad form over munster losing yesterday, edited now