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 Post subject: Signal quality problems- tried baluns, ground loop isolators
PostPosted: Mon Nov 20, 2017 11:02 am 
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Hello, please help! I'm getting video signal interference problems. I have tried ground loop isolators, baluns, and combinations of both and STILL can't get rid of the crap on my screen!

All my installations so far have used the same cheap 12v Ebay cameras and cat5 cable. Sometimes I get interference problems, sometimes I don't. I did one installation with 12 cameras and didn't need to use a single balun-all pictures had great quality. On another 12-camera installation, I had to use baluns and GLI's on ALL cameras just to make them look half way decent, and yet still have quality issues.

Even more confusing, the installation with baluns and GLI's usually look fine during the day(although sometimes images flicker rapidly and are seizure-inducing, wtf?) but at night when IR-Cut switches to night mode, I get scrolling lines and ghost images drifting across the screen. Then they clear up and look fine when light levels change back to daytime.

I usually run 3 cameras on each cat5 cable and leave one twisted pair for power. Is having the power this close to the signal wires the cause of my problems? Does running a separate power wire have any bearing on how much interference is induced into the signal wires?


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 Post subject: Re: Signal quality problems- tried baluns, ground loop isola
PostPosted: Mon Nov 20, 2017 11:30 am 
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bmw1999m3 wrote:
Hello, please help! I'm getting video signal interference problems. I have tried ground loop isolators, baluns, and combinations of both and STILL can't get rid of the crap on my screen!

All my installations so far have used the same cheap 12v Ebay cameras and cat5 cable. Sometimes I get interference problems, sometimes I don't. I did one installation with 12 cameras and didn't need to use a single balun-all pictures had great quality. On another 12-camera installation, I had to use baluns and GLI's on ALL cameras just to make them look half way decent, and yet still have quality issues.

Even more confusing, the installation with baluns and GLI's usually look fine during the day(although sometimes images flicker rapidly and are seizure-inducing, wtf?) but at night when IR-Cut switches to night mode, I get scrolling lines and ghost images drifting across the screen. Then they clear up and look fine when light levels change back to daytime.

I usually run 3 cameras on each cat5 cable and leave one twisted pair for power. Is having the power this close to the signal wires the cause of my problems? Does running a separate power wire have any bearing on how much interference is induced into the signal wires?


Those are the problems. If you do cheap installations, with cheap supplies and cheap labour, well, you will get cheap results.

Cameras with cat5 cable and without baluns? Oh well.


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 Post subject: Re: Signal quality problems- tried baluns, ground loop isola
PostPosted: Mon Nov 20, 2017 11:50 am 
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Okay, but, I've done several installations all using the same types of cameras and cable, yet I get different results with signal quality.

I'm trying to determine what the factor is that I'm missing. Does the proximity of the video wire to a power wire have to do with signal quality? Inductance is the only reason I can come up with.

At one house, I hooked up 12 cameras over cat5 cabling with zero baluns or GLI's and the picture quality of all cameras was perfect, so I know it's not as simple as "cheap parts, cheap labor, cheap results". There's a missing puzzle piece here.


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 Post subject: Re: Signal quality problems- tried baluns, ground loop isola
PostPosted: Mon Nov 20, 2017 3:47 pm 
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UTP cable is 100ohm, while a CCTV video signal is supposed to travel on a 75ohm coaxial cable. That is what baluns are for (balun = balancer/unbalancer), to adapt the video signal to travel over a 100ohm impedance cable, and convert it back on the other end.

Can you send a video signal over cat5 cable without baluns? Sure, it might work as you have already seen, if the distance is not too long, if there are no interference, etc. Do you have to assume it will work? No, you should assume it will NOT work. If you feel like trying, go ahead and do so, but then do not surprise yourself when you get bad results.

Same can be said about power; 2 UTP wires for three cameras? Using one UTP for a single camera is good practice when using one pair for video (with baluns!) and three pairs for power. You want to try to power 3 cameras with a single pair? Feel free to try, but again you should not think it is strange if it does not work ok if you are using bad installation techniques.


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 Post subject: Re: Signal quality problems- tried baluns, ground loop isola
PostPosted: Mon Nov 20, 2017 4:30 pm 
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Hi. Cheap China cameras can give lots of problems .... one is the power neutral and video neutral use the same cable which is not good

3 cameras down 1 cat5 and only 1 pair for power..... your giving yourself a problem.

Installing without baluns on cat5. ..... well you have problems


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 Post subject: Re: Signal quality problems- tried baluns, ground loop isola
PostPosted: Tue Nov 21, 2017 8:09 pm 
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So today I ran a totally separate thick gauge power wire for all my cameras. That may have have solved a volt-drop problem I think I had(Cameras draw more power at night due to IR-cut LED's turning on. New wire seems to have fixed odd night-time distortions on camera screens). But I'm still getting some slight drifting waves/lines on my screen for some cams regardless of light levels.

They all have baluns and some have GLI's. I just can't figure out how to make this interference go away.

Do I need to buy baluns with a certain rating/specification? Do I need to match it to the cable length? I'm using passive baluns and the furthest camera is a only couple hundred feet away at maximum. Do my cameras all need to be the same make/model? Are the signals somehow different and are being induced into neighboring wires via electromagnetic fields?


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 Post subject: Re: Signal quality problems- tried baluns, ground loop isola
PostPosted: Wed Nov 22, 2017 12:58 am 
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bmw1999m3 wrote:
So today I ran a totally separate thick gauge power wire for all my cameras. That may have have solved a volt-drop problem I think I had(Cameras draw more power at night due to IR-cut LED's turning on. New wire seems to have fixed odd night-time distortions on camera screens). But I'm still getting some slight drifting waves/lines on my screen for some cams regardless of light levels.

They all have baluns and some have GLI's. I just can't figure out how to make this interference go away.

Do I need to buy baluns with a certain rating/specification? Do I need to match it to the cable length? I'm using passive baluns and the furthest camera is a only couple hundred feet away at maximum. Do my cameras all need to be the same make/model? Are the signals somehow different and are being induced into neighboring wires via electromagnetic fields?


200 feet... and powering 3 cameras over two UTP cat5 cables. Yup.

Try using a good cable.


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 Post subject: Re: Signal quality problems- tried baluns, ground loop isola
PostPosted: Wed Nov 22, 2017 8:34 am 
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Securame wrote:
bmw1999m3 wrote:
So today I ran a totally separate thick gauge power wire for all my cameras. That may have have solved a volt-drop problem I think I had(Cameras draw more power at night due to IR-cut LED's turning on. New wire seems to have fixed odd night-time distortions on camera screens). But I'm still getting some slight drifting waves/lines on my screen for some cams regardless of light levels.

They all have baluns and some have GLI's. I just can't figure out how to make this interference go away.

Do I need to buy baluns with a certain rating/specification? Do I need to match it to the cable length? I'm using passive baluns and the furthest camera is a only couple hundred feet away at maximum. Do my cameras all need to be the same make/model? Are the signals somehow different and are being induced into neighboring wires via electromagnetic fields?


200 feet... and powering 3 cameras over two UTP cat5 cables. Yup.

Try using a good cable.


I'm using totally separate 18-gauge wires(pair in a shielded sheath) for power. Videos signals are going down Shielded Twisted Pair (STP) Cat5. None of the cat5 pairs are being used for power.

Do I need to buy baluns with a certain rating/specification? Do balun ratings need to be matched to cable length? Do cameras all need to be the same make/model? Are the signals somehow different if the cameras are different? Is it possible that signals are bleeding into neighboring wires via electromagnetic field inductance? If so, should I run the signals down a specific set of pairs or limit the number of cameras on each cat5 cable?


Last edited by bmw1999m3 on Sun Nov 26, 2017 5:28 pm, edited 2 times in total.

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 Post subject: Re: Signal quality problems- tried baluns, ground loop isola
PostPosted: Fri Nov 24, 2017 3:19 pm 
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well in addition to all the other things mentioned do you have your cables running near higher voltage ac lines.

Have you figured out how much it has cost you to go back and redo this as opposed to doing it with the proper wire connectors and power supply? plus it still sounds like it is not correct.


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 Post subject: Re: Signal quality problems- tried baluns, ground loop isola
PostPosted: Sun Nov 26, 2017 1:47 pm 
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Ok so I wanted to give an update since I've made progress on fixing this problem. I tied together the foil shield/sheath of the STP cat5 cable to the power ground. My theory on what happened is this: I have several cameras mounted next to a wooden carport with a sheet metal roof. The camera wires run right up next to the sheet metal roof and I think it was acting like a big antenna, absorbing or amplifying ambient EMF signals in the air and causing them to be inducted into the signal wire. Since I neglected to connect the foil shield to anything, I think the transient voltages were building up in the foil sheath and being inducted into the signal twisted pairs. When I connected the foil shields to the power supply ground wire, it neutralized the potential that was building up in the foil shield and directed it all to ground. So this leads me to believe I wasn't really having a ground loop problem so much as I was having an interference problem. If anyone has experienced this problem before or has any thought on this, I would be glad to hear from you.


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 Post subject: Re: Signal quality problems- tried baluns, ground loop isola
PostPosted: Sun Nov 26, 2017 4:41 pm 
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Hi. That was brave to wright so much crap.

1000s of engineers use cat5 in alsorts of environments and not have that problem..... as it does not exist.

What size cat5 are you using

How many pairs are you using for video

How many pairs are you using for power

What is camera distance ?

Ground loop is mainly coax using cat5 it does not exist so what type of baluns are you using


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 Post subject: Re: Signal quality problems- tried baluns, ground loop isola
PostPosted: Sun Nov 26, 2017 5:25 pm 
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tomcctv wrote:
Hi. That was brave to wright so much crap.

1000s of engineers use cat5 in alsorts of environments and not have that problem..... as it does not exist.

What size cat5 are you using

How many pairs are you using for video

How many pairs are you using for power

What is camera distance ?

Ground loop is mainly coax using cat5 it does not exist so what type of baluns are you using


I already answered those questions in my previous comments.... but so much of what I "wright" is "crap" anyway.


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 Post subject: Re: Signal quality problems- tried baluns, ground loop isola
PostPosted: Sun Nov 26, 2017 5:49 pm 
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Yes your last post was crap....... it does not happen.

But why are you using shelded 18g for power ???


If your using cat 5 for 3 cameras ..... how are you terminating the ends ?


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