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CCTV Interference Problems

Discussion in 'Home Automation, Lighting, Security & Climate' started by joe.reynolds, Jul 30, 2009.

  1. joe.reynolds

    joe.reynolds Member

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    First time I have posted so I hope I'm posting to the right section. I've read some great posts and hopefully someone can help me.

    Anyway my problem is there is interference somewhere between my surveillance camera and the LCD. The current setup is basic. It contains the camera, a siamese cable (100 ft coax and power), a BNC to VGA converter, and the monitor. I have read up on CAT5e/6 STP and thought of this as a possible solution but am unsure how to create a cable and not sure what converters would be best (I have experience making CAT5 networking cables). I know that the less converters the better. If you need more details feel free to ask. Any suggestions or are appreciated.

    Thanks,
    Joe
  2. alchad

    alchad Member

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    Joe,

    Hi. I'm definately a novice in these matters, but as nobody else has offered advice, I'll pass a couple of comments based on my own CCTV system.

    Firstly have you come across these

    Pair of CCTV Camera Video Power Balun UTP Transceivers on eBay (end time 07-Aug-09 16:03:05 BST)

    They alow you to mount the camera up to 100 metres away any send power down a CAT5 cable and get the camera signal back. You just need a BNC to RCA connector at the camera end (assuming the camera has a BNC connection) and a simple phono RCA connection between the other end and the TV (most TV's seem to still have phono plug in connections.)

    Any queries, come back or PM me.

    Regards

    Alchad
  3. joe.reynolds

    joe.reynolds Member

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    Alchad,

    Thank you for your response.

    What you have suggested looks like a possible solution. The interference is caused by motors and other machinery in the facility. The page states that these Video Power Balun UTP Transceivers have cross talk and noise immunity (50 dB Cross Talk and Noise Immunity). Is noise something other than interference? Do you know where I could find coax cable specs for comparison? Does anyone have experience where coax had significant interference and switching to CAT5 UTP fixed the problem?

    I don't know how much of a factor it plays but I am hooking this up to a LCD monitor. I am doing this using a BNC to VGA connector/converter (the monitor has a VGA and a DVI port).

    This is the first time I have installed a CCTV system so any other pointers are welcome.

    Thanks,
    Joe
  4. alchad

    alchad Member

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    Joe,
    As I said, I'm not an expert and don't know anything about the relative cable specs, however one point to watch out for is that the Ebay link is from Hong Kong/China and sometimes the translations can be a bit iffy.

    Just a few more comments of a practical nature.

    1) Can you try out the camera with say an ordinary TV which has an AV video input to see if it's the BNC to VGA convertor which might be causing a problem. I've no experience with the BNC - VGA convertors, are they just a straight wire type convertor or are they electronic?

    2) I assume the camera uses a small 12 volt power supply unit, sometimes these can play up and cause interference. They are cheap, a spare is always useful, so buy another and see if that helps.

    3) Is it posible to try the camera/LCD combination away from the facility to determine if the motors/whatever are actually causing interference or it's the camera/LCD itself.

    4) Could you try the camera with the LCD immediatey next to it with just a metre or so of cable.

    Good luck

    Alchad
  5. hornydragon

    hornydragon Member

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    I have often found that there are some so seriously cheap and nasty converters being used for CCTV cams and they can be the issue try the camera on a shorter length 100ft while not massively long is enough to cause a cheap camera with cheap PSU to struggle can you locate the PSU near the camera and send just video to monitor?
    Last edited: Aug 4, 2009
  6. joe.reynolds

    joe.reynolds Member

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    Alchad,

    To answer question 1, I don't have TV to test this on. As for the BNC to VGA, I believe it has electronics but am not certain.

    To answer your last 3 questions, I have tested this system in the facility to find a good location for the camera (using the exact same parts). Everything during the test was OK. So I know this setup is capable of showing a nice image (doesn't need to be perfect). The only difference with the test and the current setup is the monitor is mounted and the cable has been ran (during the test it was strung where it needed to be).

    hornydragon,

    The BNC to VGA converter that I am using tested OK when I was testing to find a good location.

    The cable is a premade cable and I don't have the tools to create a coax cable with BNC ends.

    Any other suggestions are appreciated

    Anyone have a good experience with Quad shielded coax or would that not likely help the problem?
    Thanks,

    Joe
  7. hornydragon

    hornydragon Member

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    Mplin will sell a short BNC cable for a few £ get one and test it (make sure its 75 Ohm)
  8. joe.reynolds

    joe.reynolds Member

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    I am 100% that the interference is coming from the conveyor system because when the conveyors are shutdown the picture is great. It's not the cable length or the converter. Is there a special type of cabling that reduces or blocks that type of interference?

    Thanks,
    Joe
  9. joe.reynolds

    joe.reynolds Member

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    I am going to try the Balun UTP transceivers. The twisted pairs help with interference from what I've read. I'll be sure to post my results.

    Thanks again,
    Joe

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