CAT 5 cable and multiple cameras

[andrewinpopayan 0]

I don't know if this has been asked before, I have had a look through a lot of posts but can't find a situation that is the same.

 

I want to run 5 cameras (each with own seperate power supply) and run the video output up each twisted pair of cables. I will put a balun at each end of the pairs and feed video into a DM DVR. Am I looking to get a lot of crosstalk and problems?

 

Thanks in anticipation.

 

Andrew

Further note. After hooking everything up I have a >lot< of noise/bars etc, could it be an effect of living within 200m of a National grid HV pylon and my cables running more of less parallel to the pylon cable run??

[GrouchoBoucho 0]

I don't know if this has been asked before, I have had a look through a lot of posts but can't find a situation that is the same.

 

I want to run 5 cameras (each with own seperate power supply) and run the video output up each twisted pair of cables. I will put a balun at each end of the pairs and feed video into a DM DVR. Am I looking to get a lot of crosstalk and problems?

no, there are no inherent problems with doing this. of course, regular cat5e is only four pairs, thus a max of four cameras - you'll need two runs to do all five.

 

Thanks in anticipation.

 

Andrew

Further note. After hooking everything up I have a >lot< of noise/bars etc, could it be an effect of living within 200m of a National grid HV pylon and my cables running more of less parallel to the pylon cable run??

that's quite possible. utp is usually very good at rejecting noise, and the balanced line makes it even better, but at some point the laws of physics always come into play. noise like that could come into the system anywhere - through a single camera, directly into the dvr, etc.

 

i would suspect a ground loop but if each camera has an individual power adapter, that shouldn't be a problem.

[andrewinpopayan 0]

i would suspect a ground loop but if each camera has an individual power adapter, that shouldn't be a problem.

 

Thanks for the reply.

 

They are all powered from seperate supplies, 12 volt 1amp switch modes "wall warts"

 

I have a stack of 12 volt alarm batteries, I will try running the cameras on them and see if it makes any difference.

 

Andrew

[Numb-nuts 1]

I sometimes run a single cat5 for each camera and it carries both video signal and power.

I go by the convention that solid color is pos and striped color is neg in amll things.

 

Now select a pair for your video and open the other pairs and twist the solid colors together and the striped colors together to carry the DC power

 

Video pair the solid is pos the stoped is neg

DC pairs the solids are pos the striped pairs are neg and use screw on terminal DC connectorsat either end a plug at the camera end and a socket at the DVR end. Of course you're better off with a single power supply with enough power to run all your cameras.

Actually I run mine through a fuse bank but it's really not essential.

[GrouchoBoucho 0]

i would suspect a ground loop but if each camera has an individual power adapter, that shouldn't be a problem.

 

Thanks for the reply.

 

They are all powered from seperate supplies, 12 volt 1amp switch modes "wall warts"

 

I have a stack of 12 volt alarm batteries, I will try running the cameras on them and see if it makes any difference.

i'll bet it won't. using separate supplies breaks the most common ground loop problem (although there my be other types of ground loops that aren't power-related).

 

Now select a pair for your video and open the other pairs and twist the solid colors together and the striped colors together to carry the DC power

this is important to note: only use one pair for video; otherwise you lose the noise-rejection properties of the twisted pair.

 

Of course you're better off with a single power supply with enough power to run all your cameras.

that's fine as long as you have decent (ideally dual-voltage) cameras, but can create ground-loop problems with cheap cameras.

[andrewinpopayan 0]

I have sorted out a camera that was causing most of the noise/hum, it was an old mains powered unit that had gone sick, worked ok but put hum on the line.

 

thanks for all the answers/suggestions

 

Andrew

[yakky 0]

You also want to make sure you have real, quality baluns. I picked some crappy ones up and had all sorts of issues that made me question using CAT5. They turned out to be nothing more than balun style connectors, they didn't actually have any circuitry inside.

[andrewinpopayan 0]

yeah cheers yakky, these are el-cheapo fleabay one's. I have a spare one so I might prise it apart and take a look.

 

Andrew

[GrouchoBoucho 0]

they look like this?

 

[andrewinpopayan 0]

Sheeet they do, feeling that these are crappos errr f*ctover

 

 

additional afterwards (twat$)

Item Description

 

High quaility product,Brand new.

This item is a adapter that use the coaxial cable convert to Camera CCTV BNC twisted-pair. With no Balun.

he coaxial cable have a better capacity of resisting disturbance，good transmission quality、energy saving、high reliability、easy to assemble and low costs.

At distances up to 50m，its capacity of resisting disturbance is equal to the the device with Balun.And it is more costs saving.

It is a best choice for the short line equipment.

No power required

 

Package Included:

8X BNC Convertor

[GrouchoBoucho 0]

reading that description hurt my brain...

[yakky 0]

hahaha.... same ones I fell for!

[andrewinpopayan 0]

hahaha.... same ones I fell for!

 

Yeah : lol, I will buy a good one and pull it apart, I don't think theres anything complicated inside, maybe a few turns of wire on a ferrite core/bead. cost pennies to make.

I'll let you know what I find.

 

Andrew

[GrouchoBoucho 0]

this is a diagram for a tv antenna balun (converting between coax and the old 300 ohm twin-lead antenna wire)... but other than maybe a couple ceramic caps for filters, video baluns are pretty much the same internally:

 

[yakky 0]

I've had good luck with these:

 

http://www.amazon.com/PAIRS-Mini-CCTV-Video-Balun/dp/B00442G9O6

 

Just slightly more than the fake ones.

[andrewinpopayan 0]

I've had good luck with these:

 

http://www.amazon.com/PAIRS-Mini-CCTV-Video-Balun/dp/B00442G9O6

 

Just slightly more than the fake ones.

 

I just bought a full set of these.

http://www.ebay.co.uk/itm/271098287762?ssPageName=STRK:MEWNX:IT&_trksid=p3984.m1497.l2649

 

I take it that you are in the USA Yakky?

[andrewinpopayan 0]

http://www.ebay.co.uk/itm/271098287762?ssPageName=STRK:MEWNX:IT&_trksid=p3984.m1497.l2649

 

These arrived today and make a WHOLE world of difference.

[yakky 0]

Yep, in the USA. Glad things worked out for you! Happy Holidays.