westy1 Posted February 10, 2020 Share Posted February 10, 2020 Good Evening, I recently took over the maintenance of a large office complex with a system of 30 cameras linked to one DVR, at least half of the cameras have interference which presents as a tearing picture in most instances. I just wondered what advice you may have for removing the problem or at least minimising it as much as possible. Thank you in advance Link to comment https://www.thesecurityinstaller.co.uk/community/topic/43526-site-with-terrible-interference/ Share on other sites More sharing options...
datadiffusion Posted February 10, 2020 Share Posted February 10, 2020 Analogue cameras? Humbug device? So, I've decided to take my work back underground.... to stop it falling into the wrong hands Link to comment https://www.thesecurityinstaller.co.uk/community/topic/43526-site-with-terrible-interference/#findComment-495194 Share on other sites More sharing options...
al-yeti Posted February 10, 2020 Share Posted February 10, 2020 2 hours ago, westy1 said: Good Evening, I recently took over the maintenance of a large office complex with a system of 30 cameras linked to one DVR, at least half of the cameras have interference which presents as a tearing picture in most instances. I just wondered what advice you may have for removing the problem or at least minimising it as much as possible. Thank you in advance What steps have you carried out so far to isolate the problem Link to comment https://www.thesecurityinstaller.co.uk/community/topic/43526-site-with-terrible-interference/#findComment-495209 Share on other sites More sharing options...
westy1 Posted February 10, 2020 Author Share Posted February 10, 2020 I have tried another wall mount power supply but with no improvement, I also switched some cameras just to see if the problem carried over but my guess would be groundloop. I was thinking of trying some groundloop isolators like these https://www.dtsdigitalcctv.co.uk/proddetail.asp?prod=CON701. Never used them before but I can't think what else might be causing it, I've ran out of ideas so maybe just clutching at straws. Any other ideas welcome. Link to comment https://www.thesecurityinstaller.co.uk/community/topic/43526-site-with-terrible-interference/#findComment-495222 Share on other sites More sharing options...
MrHappy Posted February 10, 2020 Share Posted February 10, 2020 change to 24vac & convert to 12v at every camera Mr Veritas God Link to comment https://www.thesecurityinstaller.co.uk/community/topic/43526-site-with-terrible-interference/#findComment-495225 Share on other sites More sharing options...
sixwheeledbeast Posted February 11, 2020 Share Posted February 11, 2020 It will need some investigation work to find out where the interference is getting on the system. From what you have said I would start looking for a ground loop initially, so a good start on commercial is things like the cameras mounted on metal surfaces. Ground loops are the type of thing that can effect multiple channels when there could only be one channel at fault so disconnect any with a fault until all is clear. Testing for AC in the mV range on the cable is another way to locate. Test and reconnect until you narrow it down. 1 Link to comment https://www.thesecurityinstaller.co.uk/community/topic/43526-site-with-terrible-interference/#findComment-495250 Share on other sites More sharing options...
aissecur Posted February 11, 2020 Share Posted February 11, 2020 Assuming its a coax based system and not CAT 5, can you review the cabling routes on the cameras with issues? Do they run through any switch rroms? Are the cables routed next to any LV / HV cables? Link to comment https://www.thesecurityinstaller.co.uk/community/topic/43526-site-with-terrible-interference/#findComment-495252 Share on other sites More sharing options...
al-yeti Posted February 11, 2020 Share Posted February 11, 2020 14 hours ago, westy1 said: I have tried another wall mount power supply but with no improvement, I also switched some cameras just to see if the problem carried over but my guess would be groundloop. I was thinking of trying some groundloop isolators like these https://www.dtsdigitalcctv.co.uk/proddetail.asp?prod=CON701. Never used them before but I can't think what else might be causing it, I've ran out of ideas so maybe just clutching at straws. Any other ideas welcome. Strange question for you , do you see a potential on the earth ? Of the coax and DVR Link to comment https://www.thesecurityinstaller.co.uk/community/topic/43526-site-with-terrible-interference/#findComment-495255 Share on other sites More sharing options...
westy1 Posted February 11, 2020 Author Share Posted February 11, 2020 17 hours ago, MrHappy said: change to 24vac & convert to 12v at every camera Have you tried this from experience or is it just a suggestion? 3 hours ago, aissecur said: Assuming its a coax based system and not CAT 5, can you review the cabling routes on the cameras with issues? Do they run through any switch rroms? Are the cables routed next to any LV / HV cables? Cables do not run near any other cables or lighting. Link to comment https://www.thesecurityinstaller.co.uk/community/topic/43526-site-with-terrible-interference/#findComment-495256 Share on other sites More sharing options...
MrHappy Posted February 11, 2020 Share Posted February 11, 2020 1 hour ago, westy1 said: Have you tried this from experience or is it just a suggestion? central 12v power supply(s) ? Mr Veritas God Link to comment https://www.thesecurityinstaller.co.uk/community/topic/43526-site-with-terrible-interference/#findComment-495257 Share on other sites More sharing options...
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