2 replies to this topic

[logifuse]

You've probably seen those baluns that allow you to run component video (sometimes plus digital audio, sometimes plus remote control extension) over an Ethernet cable.



Well I recently replaced my old Foxtel iQ with an iQHD. The iQ used to feed my bedroom TV via the inbuilt modulator & I use a wireless IR remote extender to control it, & while that worked ok, the picture was rubbish & the iQHD doesn't have a modulator, so I needed a new solution. Running any new cables was going to be all too hard, so I had to fit it to the existing cables. That meant I had an RG6 & an Ethernet cable.

The obvious solution was either HDMI or component baluns. HDMI was out because the crappy Toshiba TV in the bedroom can't get digital audio in sync, & component plus SPDIF was a problem because the TV doesn't support combining those 2 in to an input (did I mention it was a crappy Toshiba?). Besides, it probably would have been out of sync anyway. What I needed was Component with L + R analogue audio. The best part was that I got the TDC850NF which has HDMI plus SD or HD component (the newer TDC851NF only has HDMI plus SD component), so connections weren't a problem & I could have HD on both my TVs.

So what to do? I suspect that the lack of a balun with my required connections is because there are only 4 pairs of wires in an Ethernet cable. When you consider that 1 wire of each pair just carries ground, there's no reason that it has to be that way. Time to experiment & see if I could make something.

So what I did was this. I got 2 RJ45 sockets with punch down connections, a cheap component cable & a cheap L + R cable (I had all these lying around). I cut the cables in half & stripped the outer back, twisted the grounds in to a single strand, & then punched the component cables in to pairs with their grounds. Then I punched the L + R in to the remaining pair & punched their grounds in to 2 of the component grounds. I matched the pattern on the other socket & then continuity tested both "leads" to check for shorts. Then I put an Ethernet cable between them & checked for continuity & shorts - all good.

At this stage, the leads needed some reinforcement, so I put a cable tie around the component & L + R cables where they leave the socket & then taped up the exposed rear of the socket with electrical tape. I did one lead & then continuity tested & then did the other lead - if you do both at once & introduce a fault, it's harder to find where it is.

 ComponentEthernet.jpg   19.38K   38 downloads

So to testing. Hooked it up & hey presto, perfect HD component & in sync stereo audio, & my wireless IR sender still does that part.

To be fair, it's a shortish Ethernet run (maybe 10m total), so results may differ, but for less than $20 worth of parts it's great. Just wish I'd taken photos while I was assembling them.

Justin

[dave1234]

Been meaning to try this to share foxtel in another room hehe. Don't quite follow what you mean by twisted the grounds in to a single strand but probably make sense if I cut a cable!

They sell Component/Digital Audio over single Cat5 baluns. Wonder if you could do the same thing here instead of L&R audio? They're only ~$50 but I'm a tight arse lol

http://pro2.com.au/5...ideo-digital-2/

[logifuse]

Yeah, it would work with a single digital audio line instead of L+R analogue.

The cables are a central signal wire in a plastic sheath, & then surrounding that is the shielding which will be wire in a braid. You need peel that braid & bunch it up on one side of the cable & then twist that so that it forms a single strand that can be punched down in to an RJ45 socket.

 RCAStripTwist.jpg   32.4K   18 downloads

Edit: Unlike the photo, don't strip the plastic off the centre wire - punching it in to the socket will make the required contact while keeping the wire isolated.

The problem for my scenario is that I have 5 signal wires & 5 grounds, but only 8 Ethernet wires to to run them over. Obviously the 5 signals need to be kept apart, but the grounds can be combined. For you, you should be able to just use 4 pairs (signal plus ground) without messing around.

I should add, I recently moved house & had the opportunity to run new cables, so it's now running over Cat 6 over a distance of about 20m including a few twists & turns. Working beautifully.

Justin