How to use baluns for connecting cameras

[jdelacruz 0]

I am very new to this type of work. A little background. I'm a manufacturing engineer at a cabinet manufacturing plant. About a month ago my boss tells me that I'm on the security camera project (with absolutely no knowledge on it) and I need to get these cameras up and running.

 

I am not completely sure on the specs of the computer but I know we are running GV-1480 Series on a PC. Since I have been on this project, we have set up 5 cameras using the siamese cables from ispyvision.com. We have 11 more cameras to set up, however we have run into a slight issue. As we are getting to the last few cameras, we are definitley going to run out of the siamese cables. From talking to my boss, he said something about hooking it up with a CAT-5 cable.

 

Today, I just found out that our whole package came with about 6 Twisted Pair Video Transceivers for CCTV. So my question is would it be more cost effective to get more siamese cables or start using some of our CAT-5 cable that we already have (however the CAT-5 would still need to be run). From doing a bunch of reading on the internet I also have a few questions about the balun/CAT-5 setup (I haven't found any answers to some of these specific questions online). Now to the questions...

 

1) As stated earlier what would be more cost effective, CAT-5 or another 1000 or 2000 feet of siamese wiring?

 

2) If using CAT-5 cable, would I need to have a special power adapter to get power to our cameras? What is the average cost?

 

3) Would I be able to just run a single CAT-5 cable to the camera, and then to our pc DVR system, then just hook up the baluns to both ends (for the video) and then just use the other left over pairs to run power?

 

Any help would be greatly appreciated as I am completely confused and lost. Thanks in advance for any help!!!

[kensplace 0]

1) As stated earlier what would be more cost effective, CAT-5 or another 1000 or 2000 feet of siamese wiring?

 

Cat5 should be available cheaper than siamese, normally you would have to figure out the cost of the cat5 + Baluns, but if you already have enough baluns then that additional cost does not matter. Bear in mind you will need 2 baluns per camera.

 

2) If using CAT-5 cable, would I need to have a special power adapter to get power to our cameras? What is the average cost?

 

As long as the camera's are low voltage (NOT MAINS, for your own and others safety never use mains with baluns, or over non mains rated cable.) then the cat5 cable will cope with the power for the camera, just like siamese cable. Just dont exceed the volts/amps rating for the cable. Low voltage 12v or 24v cams should be fine, whatever you used to power them over siamese can be used for the cat5.

 

3) Would I be able to just run a single CAT-5 cable to the camera, and then to our pc DVR system, then just hook up the baluns to both ends (for the video) and then just use the other left over pairs to run power? -

 

Yes, thats the normal method for using a pair of baluns, one at each end, and another pair of cables for power.

 

If you dont already have sufficient baluns for the cameras that are left to be installed, then the question becomes, whats cheaper, siamese cable, or cat5+2 baluns per camera.

[jdelacruz 0]

Thanks for the answers Ken! One thing that I really do want to understand, when connecting with the CAT-5 as is, does it matter which pair goes to the camera or power? Or just as long as they are the same pair on both ends?

[kensplace 0]

As long as you have the same pair at both ends for power, and another pair same at both ends for video then that will be fine. Make sure you obsvere polarity, positive at one end going to the same coloured wire for positive at the other end, and so on.

 

Just make sure you dont mix wires from different pairs, the video must be transmitted over a twisted pair to ensure the signal is sent without interference.

 

Make sure you dont buy *shielded* twisted pair cable, standard unsheilded cat5 or cat5e should be fine, the NVT (balun makers) state that shielded twisted pair should not be used, as it severely degrades the signal on longer runs.

 

Its not important which pairs you use, as they should all be rated the same, but if possible I would recommend picking a colour pair for power, and a colour pair for video, and using the same colour pairs for each camera you wire up on a different cable.

 

Logic behind it being, its much easier for people in the future if they know that you always used red/black (standard for power if those colours are available as a pair) for power, and that the same coloured cables are always used for video. Makes fault finding easier, if things are all laid out the same.

[kensplace 0]

ps, dont forget if the cable runs are long to work out the voltage drop, to make sure the cable you run is ok for the length. The longer the cable, the more voltage is 'lost' on the way to the camera, if to much is lost, it wont operate.

 

If the cable runs are not particularily massive then you should be ok, but worth bearing in mind if a long run.

 

The manufacturer/supplier of the cable should be able to give you specs on voltage drop for the cable/lenght of the run.

[jdelacruz 0]

Well, I just tested out a camera using the CAT-5 cable right where the DVR is at. It worked perfectly! That was going to be my next question there, our maximum length that we would lay out these cables would be 500 feet. I am not too sure about voltages across cables, but to your knowledge do you think that standard a CAT-5 cable would lose voltage over that length? Thanks again for your help!

[kensplace 0]

Depends on a number of factors, the gauge of the wire, the power drawn by the camera, and length of cable.

 

The more power the camera draws, the bigger the voltage drop will be.

Just measured a 12v baxall cctv cam, it uses 200ma, or 0.2amps at 12v so a typical camera does not use much power, obviously some camera's may draw more, some less.

 

There are a couple of online calculators for voltage drop, one is

 

http://www.gweep.net/~sfoskett/tech/poecalc.html

 

There is nothing stopping you from using more than one pair of wires for power, if you have spare pairs, as the more pairs you use, the less the resistance,and the less the voltage loss.

 

Not really done any 500m runs with cat5, so cant say for sure how it would go, it also depends how sensitive the camera is, some dont mind running at a lower voltage, some hate it!