I want to install a camera that is around 40m from the DVR and not near a convenient power supply. Video cable was going to be rg6 coax and there's no audio requirement. The camera requires 12v with a max of 500ma. For the power I envisaged feeding a 24V/1A power supply into a in-line rectifier/regulator (output 12v max 1000ma) and then supplying power to the camera via a cable pair.

What cable should I use over that sort of distance?

I thought about using cat5/6 for the video/power wiring but don't want a loss in video quality and I believe it's hard to get quality equipment to do the job.

thanks

Edited February 13, 200719 yr by basilb

Cat5 with balluns for video on 1 pair and 12-volt power on another pair over 40m should be fine.

Only issue could be the camera you choose, many manufacturers recommend only using a regulated power supply, (like an encapsulated transformer - you see them everywhere, telephones etc), but these might drop a small amount of voltage over the cable run and depending on the voltage tolerance of the camera could affect its use.

I have successfully used regulated boxed security psu's in similar situations without problems (they typically produce a bit over 12-volts, normally around 13.5-volts but the voltage can be adjustable). You would need to check with the manufacturer of the camera you are buying regarding suitability and voltage tolerances.

tbh if it really want 500ma then it wont be, if be looking at .75mm flex at that load over that distance. probaly doesnt need .5A though

You want to avoid using CAT5 for power. If you have to, use a 1 Amp regulated DC suppy, and that should be fine.

I thought about using cat5/6 for the video/power wiring but don't want a loss in video quality and I believe it's hard to get quality equipment to do the job.

Not particularly, any reasonable quality balun will give as good an image over 40m as RG59 would.

For the power if using cat5e cable I would use the spare cores (probably 2 pairs) for the power. If you were going to use the RG59 option then 0.75mm flex or 8 core alarm cable (4 for +ve, 4 for -ve) could be used. The alarm cable will drop just under 1 volt over about 40m, the 0.75mm flex slightly less.

Thanks for the advice.

Cat5 would certainly be a neater solution. Any suggestions on what baluns to use? Ones i've seen range from $20 to $50 but I've no idea on whether the more expensive ones are better. I'm in Aust BTW.

i can recommend NVT or pelco. Everything else i have used is just plain carp!

Colin he is asking about baluns now, what do you mean?

fair enough but as you quoted my response about the baluns you can see why i was confused

Probably my fault by starting with a power question & getting led into using cat5 for video. Well I'm learning interesting stuff anyway.

As for fitting the voltage converter at the camera end - that's a good point. Only problem for me is that it's being fitted on the outside of a double brick wall so it would be difficult to conceal the wires plus the converter. Would it be worth the effort you think?