CCTV Over Cat-3 - Electrical - DIY Chatroom Home Improvement Forum

 DIY Chatroom Home Improvement Forum CCTV over Cat-3
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07-28-2012, 04:09 PM   #1
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## CCTV over Cat-3

Running 4 X10 B/W cameras about 150 feet, each using a Cat-3 line. Each 8 wire strand has four lines in use: 2 for power, 12V DC 80mA and 2 for the video signal.

There is no video from any of the cameras on the monitor.

Should I put the power source closer to the cameras?
Can the Cat-3 even hold a CCTV signal over that distance?

Thanks again for the help.

08-06-2012, 02:51 PM   #2
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According to one calculator I found online (being too lazy to do the math myself), if your CAT-3 is 26AWG, then you've dropped one volt at the end of the line when pulling 80mA. This might be enough to make a difference in whether the camera works or not.

You should measure what is the voltage at the end of the run across the conductors when the camera is connected and the system is on. Also, since use the remaining 4 wires as well to carry power, thereby decreasing resistance. (i.e. three wires in parallel for positive, three wires in parallel for negative)

Have you tested with a short length of cable that the camera and rest of system works?

http://www.calculator.net/voltage-drop-calculator.html?material=copper&wiresize=133.9&vol tage=12&phase=dc&noofconductor=1&distance=150&dist anceunit=feet&eres=.08&x=61&y=9

08-06-2012, 09:35 PM   #3
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## Will do...

I will you suggestions when I get back to the project in about a week. Thank you also for the link.

 Tags cat3 , cat5 , cctv

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