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Issues with new CCTV system install at work

Discussion in 'Alarms, CCTV & Telephones' started by dannyboi2003, 25 May 2021.

  1. dannyboi2003

    dannyboi2003

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    Evening all,

    I'm after some advice with regards some issues I'm having at work with a new CCTV system that has been installed at one of our sites, a project that I have been overseeing.

    A bit of history, the site has recently been refurbished as part of which the CCTV system was updated/replaced. The old system was a very elderly analogue system consisting of 6 external pole mounted cameras (2 x PTZ dome & 4 x fixed cameras) and one internal fixed camera. Each external pole has a direct buried armoured RG59 cable back to the the NVR and the internal has standard RG59 run internally back to the NVR. The longest external run is approx. 250 metres, there were no issues with the old system except the image quality was poor due to the age of the equipment.

    The requirement for the new system was to increase the coverage to 2 x fixed cameras per external pole (12 total) and one internal camera in the same position. A local CCTV firm who we have used previously and have a good reputation quoted me a solution that would use a multiplexer at each column to send two cameras down the one RG59 cable. Ideally we would have replaced all of the cabling but the budget simply wouldn't stretch to this as it would involve a significant amount of civil work.

    Following the installation of the new system we have had issues with the external cameras, if we connect a single camera at each column direct to the cable we get a perfect and stable HD picture. As soon as we introduce the multiplexers this is where the problems begin, typically we get one camera working with a stable HD image but the second either doesn't work at all, we do get an image but its awful quality or we get an unstable poor quality and intermittent image.

    I spent a day on site with the company today and we have tried various things, they believe we simply can't get two HD images down the one RG59 due to the age of the cabling. However they ran a new temporary cable from the NVR to the nearest column to prove this and we had the same issues, if we connected the multiplexer at the bottom of the column and tested the output with a test monitor we had a perfect image on both channels. I believe the multiplexers they have supplied just aren't up to the job, I have attached some pictures of the multiplexers being used and an example of one good image we are getting and one bad.

    I'd really appreciate any advice, specifically do any of you have any experience with these particular multiplexers good or bad and can you suggest a reliable alternative we could purchase to test? I very much believe these are the issue especially after the testing we carried out today.

    Please let me know if you require any further information, the NVR and cameras are HIKVISION, I can find out the model numbers if needed.

    Thanks in advance.
    Dan
     

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  3. dannyboi2003

    dannyboi2003

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    Edit: The pics don't show the poor quality very well, the patio image is HD perfect quality whereas the car park one is very low quality and pixelated. For example on the cameras giving us a stable HD image I can read the car number plates perfectly, on the bad images you've got no chance everything is just a pixelated blur.
     
  4. secureiam

    secureiam

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    Without knowing what you have its difficult to say.

    model of multiplex resolution cable, dvr/nvr model etc etc
    Cable runs etc etc.

    your telling me that the multiplex works but only at the bottom of the pole or one camera.

    you also suggested its been done differently to the original recommendation due to cost. What is the difference in specs?
     
  5. bernardgreen

    bernardgreen

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    I may be wrong but I think to multiplex video feeds from two cameras the camera's frame scans have to be synchronised.

    At least that is how it was with analogue video.
     
  6. sparkymarka

    sparkymarka

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    I would say those multiplexers look very cheap ….
    Also what MP are the cameras , how long is the cable run ?
    I have seen the CCTV MULE but that only supports Tvi up to 3mp …this may be your issue
     
    Last edited: 26 May 2021
  7. Swwils

    Swwils

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    If depends what they are transmitting down the cable and the cable quality and terminations can have a massive effect.

    They should of tested the cable before offering up a final design - especially as the whole project was priced/designed around not being able to change the cable.
     
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  9. Sally2000

    Sally2000

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    "I spent a day on site with the company today and we have tried various things, they believe we simply can't get two HD images down the one RG59 due to the age of the cabling"

    It's unlikely that the cable has aged in such a way that it will selectively carry one video signal but not two. The bandwidth requirement of the multiplexed signal is still far below the ability of RG59.

    I'd be looking at doing a bench test to test the multiplexer with a couple of cameras.

    Could some or all the cables be replaced with microwave links which are now very economical?
     
  10. dannyboi2003

    dannyboi2003

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    Hi Guys,

    Firstly thank you to everyone who has replied and secondly my sincere apologies for my lack of replies, I have been unwell and off work since posting this thread and only returned to work today. The issues remain as nothing has happened since I posted so I will reply to all of your responses in turn:

    Secureiam - I am still waiting for confirmation of the camera models but I have been advised they are part of the 'colorview' range. The DVR model is Hikvision DS-7216HUHI-K2/P. I dont have any info on the multiplexers being used other than the pictures I have posted, they appear to be unbranded and the boxes they came in didn't have any additional information on either. I have measured the cable distances from the DVR to each column as follows, give or take 5-10m, Column 1 26M, Column 2 58M, Column 3 81M, Column 4 100M, Column 5 183M, Column 6 237M. These cable runs are well within the quoted distance of the multiplexers and as I said if we connect a single camera down each cable without the multiplexers we get a perfect and stable image.

    Bernardgreen - I have no idea, the multiplexers supplied didn't come with any instructions just what you see in the pics. My understanding after doing some research is that some should just work when connected and others have a limit on the type of image you can put into them. As a test we have switched some of the cameras into CVBS mode and we are still having the same issues.

    Sparkymarka - I agree and I believe the multiplexers are the issue, the CCTV company say they have used them before without issue but can't confirm if it was with these particular cameras. I am unsure of the Camera's MP as they haven't confirmed the model number to me yet, I have been promised this will be with me by tomorrow but I include a picture of the cameras as installed if it's of any use. Cable runs to each column have been detailed above. We have tried switching the cameras to CVBS mode which is very low quality and the issues remain, as you said I too believe the multiplexers are our issue.

    Swwils - Testing of the cables was never discussed or brought to my attention. We did run a test cable to the nearest column, if we connected the multiplexer at the base of the column with say 5m between each unit the images came through bang on perfect. When we connected the test cable which we measured out at about 30M, this was brand new off a roll with new ends fitted, the issues returned. It's as though the multiplexers are struggling with the cable distance even though they should work up to 400M.

    Sally2000 - I agree as the old system worked fine on the cabling and we can get one camera working perfectly stable at each column on the existing cabling, only when we introduce the multiplexers do we start having the issues. We have carried out a bench test of sorts, as described above we moved one of the multiplexers receivers to the base of a column and connected it up, there would have been approx. 5M of RG59 between the units and we had 2 perfectly stable images. To rule the underground cable as the issue a test cable was run off a reel from the DVR to the column and we have the same poor quality images again. We have looked at wireless but we don't have the budget, the CCTV company are happy to work with us and as yet haven't been chasing us for payment but are looking to me for a solution, if they have supplied defective equipment then they are happy to replace it but they are looking to me to suggest something as they firmly believe the existing cabling to be the issue.

    Thanks again everyone for your help with this issue.

    Regards
    Dan
     

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  11. The Pars

    The Pars

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    Hi Dan,
    Those multiplexers are fine for the job as I have used them a lot on jobs and are from the same suppliers as the cameras.

    Check what cameras are installed as those multiplexer units will only take up to 3MP cameras. You get 2mp Colorvu cameras but then the rest are 5MP.

    On the DVR side it could be the frame rate has been set to high to cope with the cameras. Generally 3mp cameras I set to around 15 frames per second.

    My first guess is those cameras are 5MP(what does the spec say in the quote) and it’s to much for the DVR. I could be wrong though.

    But I’m sure it’s something that can be easily rectified.

    Plus and it’s from an engineers point of view I wouldnt install the big waterproof boxes to the front of the pole like that as it looks messy…
     
    Last edited: 14 Jun 2021
  12. dannyboi2003

    dannyboi2003

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    The Pars - Thanks for your reply.

    Hmm that makes sense and it's good to hear from someone who has experience with these particular multiplexers. From memory I believe the quote stated 5MP cameras, would it be possible to change this as a setting on the cameras?

    I don't think the DVR settings are the issue as if we connect a single camera at each column taking the multiplexers out of the equation we get a stable image.

    With regards the boxes on the poles, believe me the columns look 10 times better than they did before. There was a lot of redundant equipment on them before and the one I took a picture is the only one that has two boxes on it, the others all have one. They were fitted on the front for ease of access as due to the position of the columns a cherry picker is required. Overall they have left us with a very clean looking installation that I'm more than happy with aside from the picture issues obviously.

    Thanks again and I will try and pin down the model number of the cameras tomorrow.

    Regards
    Dan
     
  13. The Pars

    The Pars

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    Hi Dan,
    I’m a bit suspicious now…is this your own install? however I would contact the installer and sort out if required as you seem to be on the to helpful side and none of my customers would be like this good luck
     
  14. dannyboi2003

    dannyboi2003

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    No it's not my install but I'm certainly not your average customer. Where I work we have 7 sites, my current role is IT Projects Technical Lead and I have over 20 years experience in the IT industry. One of the projects I'm currently leading is the replacement of our entire CCTV estate which has started with this site, whilst I'm familiar with CCTV technology it's certainly not my field of expertise hence my post here for advice. I'm more helpful than most customers as I know the sites inside out with regards cable ducts/routes, electrical feeds etc. It's quicker for me to help getting issues sorted as and when they arise. This project has dragged on for too long now so I need to get it completed and signed off so we can move on to the next.
     
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