Ground Loop

[volito 0]

Searched forum and net for my problem found no answers...

 

System - 4 cameras, capture card in dedicated PC.

 

question- I am getting ground loop effects on one camera "scrolling bars up picture". I am 95 % sure it is a splice I made in cable causing this. I searched on easiest way to properly splice a High gauge "small cable approx. 22 gauge" It is also a Combination Video and Power Cable. Is it possible to get a good enough splice so I do not have to pull more cable?

 

 

Thanks in advance for any tricks or tips.

[lynndiwagon 0]

Try two BNC's and a coupling for the coax part, shouldn't make any difference on the power part.

[VST_Man 1]

22 g won't handle BNC connectors well.....it will be a mess trying to get it "tight". I would recommend soldering the connection and applying proper insulation to protect it.

 

Grond Loop is cause when a potiential between 2 objects is present causing current to flow causingbad video. Make sure the cable is routed around any other wires to ensure your poor video is not caused by inductance.

 

22g video cable is really bad stuff. it may work initially (and I tried it to understand it) but over time a 100% visually good cable just goes bad?

[Kiwi 0]

I think you would have had to do a really crappy job splicing the joint to create this problem! Perhaps the (-) leg is disconnected and the camera is returning power via the shield?

[rory 0]

just keep the video and power separated properly, wont effect all cameras but definitely some of the cheaper ones. What are the wires inside the jacket, just video, positive, and ground?

[volito 0]

Thanks for all the advice but unfortunately I won't be able to trouble shoot until the weekend. As for bad cables "I should of known better to trust the sales guy".

 

 

The only thing I can add is that the quality changes. So it can be interference.

 

I will trouble shoot your suggestions and and post results.

Thanks for your time.

[cctv_down_under 0]

Before you try anything else, if it is rolling pictures it may not be a ground loop, are you using 24VAC, if so it could be a phase shift problem...now please read carefully...ONLY if using 24VAC swap the - for the +, it is unlikely to fix the porblem but easier to test than the rest!

[Lolo Wolf 0]

just a thought...what method did you use for your suspect splice, is it outdoor and where on the run is splice located....you say the quality changes....could be a failing splice causing intermittent contact, a sloppy splice will lead to failure at some point down the road, if your splice is to blame and dependent on the length of the run maybe better to pull new and lessen the chance of haunting you later if its a short run can you lay a temp cable to the cam and see if it goes to normal

[volito 0]

just a thought...what method did you use for your suspect splice, is it outdoor and where on the run is splice located....you say the quality changes....could be a failing splice causing intermittent contact, a sloppy splice will lead to failure at some point down the road, if your splice is to blame and dependent on the length of the run maybe better to pull new and lessen the chance of haunting you later if its a short run can you lay a temp cable to the cam and see if it goes to normal

 

 

 

No special method "just stripped wire-twisted middle and power and wrapped braid back around". Also read somewhere to wrap with aluminum foil around splice. If anyone has step by step instructions or best method please advise. Will try some trouble shooting soon and also try a temp run for quick check over weekend.

 

Thanks

[rory 0]

Best method is to just twist positive to positive, ground to ground (braid), video to video, etc. Dont put the positive twisted cable ontop of the negative one, put it one way then the other the other way so they are not over each other, then tape up good and tight (test first). Video can go over either one, and once again test then tape good and tight.

 

Also, what cable was it again (see my earlier question).

 

This is not a typical CCTV connection so you wont find any definitive explanation of how to do it, it can vary from camera to camera and cable to cable, as that cable is not really CCTV cable.