cctv interference

[sparkies2306]

guys any ideas on how to sort out interference on cctv system

it has 5 cams installed on it all outside cam with i/red

3 cameras ok but 2 of them on the monitor are showing we lines across it nothing to serious but guy who we done it for starting to complain a little

thanks in advance

 

[Barx]

Would it not be best to figure out what causing the interference. Do the coax run along size mains cable, etc?

 

[ian932]

Is it domestic or commercial install, can you expand on the install?

 

[binky]

Would start by checking co-ax connectors are termianted properly - it's easy to get a whisker of copper in wrong place

 

[NozSpark]

I bought some pre terminated extension kits for a CCTV install,,,, never again!!

Ended having to replace it with shotgun and crimped RG59 connectors

 

[PC Electrics]

Are these wired or wireless cameras?

 

[sparkies2306]

sorry guys

this system is hard wired, and as far as i can see they are run along with power cables, and all controls dvr monitor all back to one room where fuse box and all othere supplies for gates, intercom are situated

the cams just have small power lead of it and rg59 end

cheers

 

[NozSpark]

It could easily be picking up interference from being alongside mains cables,,, like any signal/data cable they should really be 150mm away

 

[ian932]

With my limited Knowledge of cctv I'd suggest the following things could be done in this order.

1. Plug a test monitor in at the faulty camera position to prove the camera is good.

2. Check all plugs are made off ok (if a strand of screen is touching signal core you could check by continuity testing)

3. Connect a test monitor to the furthest point to eliminate the PVR etc.

If you get to item 3 and its clean then it

 

[Barx]

The one thing these guy

 

[Curley]

Hi,

Thin white lines on the screen are normally indicative of RF interference, look for sources of RF near to the cameras or cable run, one of the worst we come across apart from WIFI are sky+ boxes.

first to try.

turn off any prospective source to see if this cures the problem, if killing the kit works then the only way to cure the issue permanently would be to run the signals back on a balanced line (twisted pair or cat5) and use baluns.

Are the cameras all fed from the same phase? (not a problem if they are not PROVIDING! steps are taken to avoid earthloops)

How long are the cable runs?

TIP always better to stay away from causes of interference is a lot cheaper avoiding than trying to remove it.

Sean

 

[Lead-Laddie]

Do yourself a favour,I usually find that when a single poor quality PSU is used they can often cause interference, I am guessing but each camera has it;s own PSU. If thats so, try swapping a few between god and bad cameras and see if thats your problem. I once bought a 12V 5A PSU from a well known supplier in Edgware road London and unfortunately after week in situ it started to interfere. I returned and it it was replaced and that one is still a rock solid picture today.

As a last resort, for the cameras in question check the entire length or cable run for pinched coax, finally there are filters you can install called HUMBUG or ground loop isolators. The out of phase thing is called a ground loop and the strange thing is they don't always cause problems with image display but when they do, it's time for drastic measures.

I prefer 24vAV PSU as the AC is less prone to ground loop interference and voltage drop over distance. I start with 24AC and prefer body cams that can use 24V ac or 12V dc. Where the cameras are 12V I step down the voltage to 12V DC at a junction box adjacent to the camera, result, nice regulated voltage with negligible voltage drop and plenty of current available and never suffered interference with this method. You can use variations of this to supply power to a group of cameras if your transformer is suitable. If not , well it's back to 24v distr and several transformers. http://www.rexcctvinstallation.com

---------- Post Auto-Merged at 05:49 ---------- Previous post was made at 05:49 ----------

It's one or two of your PSUs.

http://www.rexcctvinstallation.com

 

[Doc Hudson]

Old thread, last posted on in May 2011, probably resolved now?

Doc H.