Ground Looping/Interference?

[BangersAndMash 0]

Hi, just joined and wondered if you could tell me which forum would be most suitable for discussing this problem I have?

 

Thanks.

[SDM Group 0]

Installation Help

[Soundy 1]

This is fine - ask away!

[BangersAndMash 0]

Hi, OK. Well, I have a single camera fed into a 4 channel DVR. The camera attached to the DVR by a 20m signal/power cable with BNC connectors. One of these:

 

http://www.amazon.co.uk/gp/product/B004I9N5RO/ref=s9_simh_gw_p60_d4_g23_i2?pf_rd_m=A3P5ROKL5A1OLE&pf_rd_s=center-2&pf_rd_r=0T9AHTQVW5KY3927S49R&pf_rd_t=101&pf_rd_p=467128533&pf_rd_i=468294

 

this is the DVR:

 

http://www.ebay.co.uk/itm/ws/eBayISAPI.dll?ViewItem&item=230697982868&ssPageName=ADME:L:OU:GB:1123

 

The picture is heavy with interference, so much so I think it actually trips the motion detector alarm in the DVR. The interference looks like faint vertical lines being badly distorted left and right, like a hairpin in a road. I have tried to plug the camera and DVR into separate power outlets and then on the same outlet and I've checked all the connectors, but no luck. I have also tried a ground loop isolator but that made the problem ten times worse. Is it because the signal/power cable is unshielded? I've read that power and signal cable should not run along side each other and 20m is a long way to run both power and signal side by side.

 

Any ideas?

[tomcctv 190]

  BangersAndMash said:

I have also tried a ground loop isolator but that made the problem ten times worse. Is it because the signal/power cable is unshielded? I've read that power and signal cable should not run along side each other and 20m is a long way to run both power and signal side by side.

 

 

 

can you list your cameras and also power supply used and what amp.

 

 

but you also have a problem with the cables ...... they are not coax so this will not help. if you dont want to change cables then i would cut off each BNC and attach a cctv balun

[Soundy 1]

Can you post pictures or a video clip showing the noise?

 

Power and video together like this is fine since the power is very low voltage, and 30M really isn't that long a run. However, you do want to avoid running your cables near any other source of electrical interference, such as lighting (especially fluorescent lights), or motors (A/C or other high-current devices, especially).

 

It's also possible if a camera is mounted to a metal surface, or if a mounting screw goes into a steel stud, that it's getting a ground loop that way.

 

And ultimately, it could just be the fact that you have a cheap, no-name, junky DVR (and I'm guessing the cameras are something equally cheap?)