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Blake CCTV

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Posts posted by Blake CCTV


  1. Sorry just read your post again and seen Coax in the title. Check the termination switch/setting on the DVR if there is one! Using a voltmeter set to Ohms go to the camera and check the resistance of the coax cable as it goes back to the DVR, it should read 75 ohms plus the resistance of the cable so probably about 80 - 100 ohms depending on the cable length/quality. If you are reading in the M ohms range then the cable is un-terminated, or has possibly been damaged, next go to the DVR and remove the camera signal lead and measure the resistance of the video input this should be 75 ohms.

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  2. This looks like reflection, normally caused when a signal cable isn't correctly terminated either due to a loose connection, a cheap Balun or if the termination resistor has been un-selected. If you are using cat5 are you using just one single pair for the video signal if not you should be. I think you are right about the power as the camera is clearly on and has no issues there. What type of cable are you using cat5 or coax?


  3. If you have a supply voltage issue at the camera end then using the shotgun cable will give better results as the 2 core for the power will have a much bigger cross sectional area (the cable is thicker than cat 5) so there will be less volt drop meaning that the camera will have the correct amount of voltage to work.

    If you have a voltmeter then check the supply voltage at the camera end, it may be fine at the PSU but a lot less once it has travelled down the cable to your camera.

    Another option if possible is the move the power supplies to the camera location.


  4. This could be a couple of things, some cheap Baluns do give interference but this shouldn't affect the other pictures, it may be some sort of ground loop issue; although Baluns claim to give ground loop isolation it still occurs.

    I would personally check the power supply voltage at the camera locations, there can be quite a volt drop on cat 5 especially if you are using 12Vdc I prefer to use 24VAC when I can.

    When you disconnect one camera there will be more voltage for the other cameras and the camera with the longest cable run will put the biggest strain on the supply.


  5. I remember using a mains powered 9" crt test monitor to adjust the focus on a tubed camera at the top of a 6m tower and using my oscilloscope most days.

    I also remember seeing the first baxall ccd camera that was really poor resolution about 300tvl


  6. Aswell as opening port 80 you need to port forward this to the dvr.

    When your router gets incoming traffic on a port that is open it will let it through but if you don't tell it where to go it won't have a clue.

    Port 80 is the default port for internet traffic and would've been open on your router anyway.

    You need to tell you router to send any incoming traffic to the ip address of your DVR.


  7. Where are you located eg UK ?

    If a camera is to see you then you should be able to see it, the only way that I know of hiding a covert camera is behind a 2 way mirror even then you can take the mirror down and check behind it.

    Cameras can be discreet but most will require wires for power and signals wireless cameras can be harder to find but will only work for as long as the battery will allow probably only a few hours.

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