av verses ac

[kevings]

hi this my first post on this forum feel free to tell me i am stupid and talking out of my elbow if you want
my question is i do know that you can use mains cables in a household circuit to carry ethernet signals is there some sort of gizmo out there that you plug in like the power over ethernet plugs that will allow you to transmit av signals over the same power cables
as i said if you think i am talking stupid feel free to slap me down

 

[tvtech]

Hi kevings

There is no question in this world that can ever be called "stupid".
It's the people that never ask or inquire that are indeed stupid. Think about it and welcome to ETO. by the way.

Someone here who has experience with your specific question will probably reply shortly.

Cheers

 

[Sceadwian]

kevings, I'm with tvtech, the only stupid question is an unasked one =) That being said though Google is your best friend! Do a search on Google for Video over power.
**broken link removed**
is the first link I came up with, bit pricey but it's a niche market item. Do some more searching yourself and try the same search terms on ebay.
Keep in mind I'm not sure if you mentioned Ethernet over power just as an example or if you're already using a network connection over your power lines but the two are almost certain to interfere with each other, the video one wouldn't work or would be full of noise and the ethernet one would have huge data loss from traffic collisions, meaning it'd try to retransmit which would cause more noise for the video, neither would end up working.

I would personally advise biteing the bullet and wiring your location with Cat 5e or better Cat6 cabling to the key points. Sites like MPJA - Power Supply, Power Supplies, Security Cameras, LCD, Fans, Etc. sell baluns which can let you attach video (via a BNC connector) over any twisted pair wiring. Seeing as how Ethernet only needs 4 wires to work there are 2 pairs of wires in standard network wiring that aren't used.

 

[antknee]

They certainly exist in the UK although they have never caught on in a big way. Even Ethernet which was supposed to be the next big thing didn't get that big. Wireless is just so much better. I remember wiring the upstairs of my house with ethernet cable 10 years ago, the cable was 40 foot long! I don't see any particular need to stick with ethernet, although you may need it for a particular reason.

 

[Sceadwian]

antknee, when wireless networks can hit 1 gigabits per second over 300 feet of range without any fear of interference through walls between any two points any number of which can exist in the same location the only limit of which is the number of ports on the systems has, you let me know =) Wireless networks and the bandwidth they use become more saturated and less useful every day.

As one who has used both wireless and wired solutions, I've found in every situation that the wired solution is better. The only case for wireless access is for those that need true floating wireless for a laptop or other remote devices that are required to be wire free. There are even economical in home fiber solutions that put copper to shame.

 

[antknee]

Wireless is currently 108MBits/s or around 12MBytes/s, lets say with losses you get 10MBytes/s, this means a dvd can be transferred in around 9 minutes, when I can watch a 90 minute DVD in 9 minutes I'll rewire my house

A wired solution with 1GByte/s Lan is faster and more reliable, I guess there is a trade off between speed and convenience. They aren't either or you can have both.

 

[misterT]

I don't know if there is any existing gizmos that allows you to transmit signals over power cables, but the concept of such a device is quite simple. You can use either capacitive or inductive coupling to interface with the power cables.

Capacitive coupling is easy to install but the problem is in the impedance matching. There exist some ICs that can automatically match impedances. These ICs are designed for mobile phones.

With inductive coupling it's easy match the impedance, but installation requires more work.

https://emcesd.com/tt2005/tt040205.htm

 

[antknee]

The technology outline is here:

Power line communication - Wikipedia, the free encyclopedia

I remember seeing one of the adapters on sale a while back, I can't remember how much it was but it wasn't an earth shattering price.

 

[kevings]

thank you all for your answers i will sertanly look on google.

 

[Sceadwian]

misterT of course such devices exist, didn't you read my posts? I even linked to a commercial device that does just what the poster wants =)

 

[kevings]

on reading all the post i would like to ask Sceadwian a question. do you mean if i split the Ethernet lines and use the two pairs that are not being used to carry the av signal whist still using the Ethernet over power adaptors this will do the job for me

 

[Sceadwian]

As long as you're not using gigabit ethernet yes, Gigabit ethernet uses all 8 wires. Standard ethernet (both 10 and 100) leaves 2 pairs unused. I think there may be a caveat if you're using power over ethernet as well, but for standard network runs, 4 wires are never used. This CAN result in noise in the video signal (especially with long runs) and MAY cause minor interferences with the ethernet data, however the high common mode rejection of the typical twisted pair cable shouldn't cause you to worry too much. Your mileage may vary.

 

[kevings]

thanks it is just a three up three down house so not very much length in the cable runs, not at home at the moment will try this as soon as as i get back and post results

 

[Sceadwian]

Keep in mind I never said you could just send unballanced video signals over twisted pair, the audio might be okay if you don't have any ground loop issues (which you probably will). You need a balun on both ends.

 

[kevings]

thanks i will pop into our electronics shop ( Maplins ) the equivalent of your radio shack and see if they can point me in the right direction

 

[Sceadwian]

It's not a common item, Radioshack sucks for anything of any real usefulness, they just rebrand cheap Chinese electronics and hock Sprint cellphones. I know you can get AV baluns that take a BNC connection (alter to taste) from mpja.com they're meant for security camera type setups where long run coax would be either costly or annoying, when you cna used the unused wires on an existing network setup.