CCTV Vertical Coloured Lines Rolling Across Screen Interference

[mrdiy88]

Hi guys. I have installed an AHD CCTV system (Hikvision) at my house. I have used solid copper cat5e cable coming from the 4 cameras into a 4 channel balun in the roofspace. Then I have ran a length of cat 5e cable from that down to the DVR. The DVR is connected to the TV via HDMI. The cameras transmit using TVI.

The cams are powered using a single 12v 5a psu and 4 way splitter in the loft.

When I have only one camera connected to the power supply the picture is perfect and very impressive. This is the same for each camera if only one is powered at any one time.

As soon as I power two or more cameras the interference appears. The main problem is the vertical scrolling coloured bars going from right to left and very slight ghosting. Sometimes I notice when i view one particular camera full screen that a ghosting images from another channel rolls across the screen. It is ever so slight. But the main concern is the coloured rolling lines. They keep triggering my motion detection.

I am not sure whether to try individual power supplies or a ground loop isolator on all 4 channels. I want the images as perfect as possible so it doesn't trigger unnecessarily.

The cams are plastic body mounted to pvc facia. The votages are perfect at each cam and wiring all good. 3 pairs used for power and 1 pair for video per cam.

Have any of you come across these annoying lines and how did you solve it.

Finally I am using a 4ch passive balun in the loft so I can send the 4 chanels down one ethernet cable to the dvr. Should there be baluns at the camera and the dvr? Even though there is a 4 ch balun in the loft? Wasnt 100% on that.

Thanks for any input

[mrdiy88]

Re: CCTV Vertical Coloured Lines Rolling Across Screen Interference

Forgot the images. See attached. This is night time but it happens in daylight too.

[ModernAlien]

Re: CCTV Vertical Coloured Lines Rolling Across Screen Interference

Hi

I am probably resurrecting a long dead thread. Do you still have this setup and problem?

I do not have working experience with TVI, but have worked with analogue.

Do I understand correctly that you have only one 4 channel BALUN? No other? You should have BALUNs on the camera and DVR side for correct working.

I have come across some very bad 4 channel BALUNS that allowed for cross talk between channels.

I would get 4 single channel passive BALUNs together. Connect two cameras using the 4 BALUNs (one at each camera and two at the DVR side). See the result. Next, try a single channel BALUN at each camera and the 4 channel BALUN at the DVR side. See the result.

Use UY connectors on the CAT5 to assure proper connections where you want to connect two CAT5 cables together. They are worth their weight in gold.

As long as the power supply is of good quality, I cannot see it causing your issue. Make sure to measure the loaded voltages if you measure. Most analogue cameras allowed about 10% variation in voltage before the images started to degrade.

[mrdiy88]

Re: CCTV Vertical Coloured Lines Rolling Across Screen Interference

Hi thanks for the reply. Yes i must say there is certainly crosstalk between the different display images when viewing. At the minute i am uaing baluns at the cameras the cables run into the loft into a 4 ch balun. The only reason i did this was to send all 4 channels down the one ethernet cable. I have no baluns at the dvr but did try them to no avail. I also tried the ground loop blocker but nothing works.

You may be onto something with the cheap 4 ch balun. It was an ebay special (lol). I might do a join as you say and just put baluns at the dvr instead. I will send away for the uy connectors. I will report the results. Many thanks

[ModernAlien]

Re: CCTV Vertical Coloured Lines Rolling Across Screen Interference

Hi

You can try to run without any BALUNs for a test. There will be some impedance mismatches, but if the cross talk stops, then the 4CH BALUN is most likely the culprit.

Ideally the setup should look like the attached document.

Some BALUN manufacturers have special models for AHD, TVI and CVI cameras. I never opened them up to compare to those for SD CCTV models. Maybe someone else can comment whether it is just a trick to charge more for the same thing or if there is actually improvement to be had?

[stj]

Re: CCTV Vertical Coloured Lines Rolling Across Screen Interference

i dont know why you didnt just use screened cable designed for sattelite or cable tv use.
there is so much over use of wiress fucking stuff these days that you pretty much need to shield everything.

[mrdiy88]

Re: CCTV Vertical Coloured Lines Rolling Across Screen Interference

Thanks I will try this and come back when i get the result. I sent away for uy connectors too. I used ethernet because i could send the power and video down the same line. The price of sat cable with power was quite dear and i already had cat5 here hence why i decided on that. I mean it does my job. Eventually I will be upgrading to ip cameras and an nvr but will try to get the interference stopped in the meantime.

Cheers again for the help

[tom66]

Re: CCTV Vertical Coloured Lines Rolling Across Screen Interference

I am wondering why you use Cat5e cable for what is a single ended analog signal that must be sent along 75 ohm cable. It needs to be transmitted along a shielded coax cable with the correct impedance and terminated into the correct impedance as well. I suspect the cable is picking up cross talk from your other cameras - the rolling bar is the colour burst signal in the adjacent camera feed which is being detected as colour video information.

AHD is virtually identical to PAL video but with non interlaced video and higher line count. I have some 720p AHD cameras that work quite well but they use BNC and coax cable. I wouldn't want to send that video along a Cat5e cable because it's an analog signal and susceptible to interference.

If you want to send power at the same time then you will need to get a cable that combines both power and coax video feed, but that cable must use separate power and ground feeds for each camera (it should NOT use the video ground.)

[TornadoAlley101]

Re: CCTV Vertical Coloured Lines Rolling Across Screen Interference

Has anyone found a solution to this? I have the exact same problem with a ZOSI 16 Channel CCTV System. Vertical lines on every camera. I am using 4 power adapters, each connected to a 4 way splitter to power all 16 cameras. When I power only one camera without the 4 way splitter the lines disappear. I am using 12v 2A power adapters for my system. I have a mix of 100ft and 50ft cables, some 50ft cables attached to each other for extra length. The cables are sold by ZOSI and they are BNC type. The cameras are all set too AVI but they support all 4 formats. The company seems clueless at what the problem could be so I decided to reach out to you guys. I doubt it is a ground loop because all of my cameras are connected to the same UPS system and my cameras are not mounted on metal surfaces. I want to try out an 18 channel CCTV Power Supply but I don't know how many amps I need. They have 10 amp and 20 amp options. I honestly don't know which one is best but if you have any better solutions please let me know!

[stj]

Re: CCTV Vertical Coloured Lines Rolling Across Screen Interference

how much current does a single camera use?

[TornadoAlley101]

Re: CCTV Vertical Coloured Lines Rolling Across Screen Interference

Here is the manual for one of my cameras:
https://cdn.badcaps-static.com/pdfs/...bf0fde4a6c.pdf
I do not know what the exact input is but I am guessing around 12v 2amp. Here is the company's website:
https://support.zositech.com/hc/en-u...wnloads-Center
You can try searching through the manuals. I have both dome and bullet cameras. I will also ask the company what the input is. Thanks!

[diif]

Re: CCTV Vertical Coloured Lines Rolling Across Screen Interference

how much current does a single camera use?

The analogue cameras are 500mA.

[TornadoAlley101]

Re: CCTV Vertical Coloured Lines Rolling Across Screen Interference

So I basically need the 10 amp 16 channel power supply?
10 amp/16 channel= about 600mAh
20 amp/16 channel= about 1,250 mAh
Required mAh per camera = about 500mAh

[dick_barton]

Re: CCTV Vertical Coloured Lines Rolling Across Screen Interference

If your sure the camera's take 500mA then the 10A power supply I would have thought would be OK but would not leave you with much room to further expand the number of camera's.

[TornadoAlley101]

Re: CCTV Vertical Coloured Lines Rolling Across Screen Interference

Update: The camera take in according to the company is 300mAh/0.3A and 12V. Is the 10A Power Supply still suitable? Will the extra 300mAh affect performance?

--New Power Consumption Chart--
Power Supply mAh per camera (10A Total)= about 600mAh
Required mAh per camera = about 300mAh
Left Over mAh per camera = 300mAh

[dick_barton]

Re: CCTV Vertical Coloured Lines Rolling Across Screen Interference

16 camera's at 300mA = 4.8Amp supply total so a 10Amp supply would have no issues.
Perhaps you could try a 12V car battery and see if you still have the colour bars before you buy your power supply.

[TornadoAlley101]

Re: CCTV Vertical Coloured Lines Rolling Across Screen Interference

Thank you, I will try this out. I will let you know the results!

[TornadoAlley101]

Re: CCTV Vertical Coloured Lines Rolling Across Screen Interference

I just tried it out and my 12v 0.5amp power supply worked but I have a few questions after I dug deeper into the problem. I decided to unplug all 3 power adapters except 1 and when I unplugged the 3rd one, the lines became less visible on the 4th power supply's cameras but still faintly visible that it was still an issue. I have a lot of devices connected to one outlet including a wifi router, wifi extender, UPS system, power stabilizer, and other devices. Is it somewhat possible that all of these devices are leaving less than enough power for all of my 4 power adapters and causing the issue? I have made a diagram of the setup I have below. Also, will purchasing a 12v 10A Power supply minimize the amount of power that my previous 4 12v Power Supply's took up? Thank you!

Diagram link:
https://docs.google.com/drawings/d/1...it?usp=sharing

Tip: When you click on an image in the diagram, the product link will appear if you need more information such as voltage.

[TornadoAlley101]

Re: CCTV Vertical Coloured Lines Rolling Across Screen Interference

Also, will purchasing a 10a power supply benefit my cameras by providing more amps than required? Is it possible I could also buy a 20a 12v power supply instead? For some reason they are cheaper than the 10a power supplies but if the 20a will mess up my cameras then I can go with the 10a instead.

[TornadoAlley101]

Re: CCTV Vertical Coloured Lines Rolling Across Screen Interference

Here are the links for the power supplies I am referring to:
20A: https://www.amazon.com/Channel-Distr...dp/B01MZ880XT/
10A: https://www.amazon.com/Channel-Distr...dp/B07QXXY987/
It seems the cheaper 10A Power Supplies are less quality so that is why I am aiming for the 20A.

--PS: Sorry if it seems I am spamming the forum. I am honestly just waiting for a reply. Thanks for your understanding.--