Dark lines on camera

pal251

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I have 4 or 5 dark lines on my IP camera that was just installed going across the video. I suspect it's the cable because it doesn't do it while plugged into the switch. I am afraid the electricians messed it up while pulling the cable. Normally I do it myself. Any ideas? I put new connections on both ends, no help. It's cat6 or cat6a
 

Probird79

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Sounds like it might be some type of interference. Try running a loose patch cable to bypass the existing line. If that is good then I would have the electrician redo it especially since you paid them. If it still happens after they replace it you may want to run a shielded cable. If they know what they are doing you can show them your problem and they might be more aware where they are running the cable.

What switch are you plugging into and what is it plugged into when you get the lines?
 

pal251

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It's a zyxel switch. Building has 30 cameras with some even being even a 360 foot span with no problems. This is only 75 foot and I don't see anything crazy next to it. It's worse at night. Next time I'm at the property I'll try the patch cable idea but the electricians were dicks and said they don't have time to run a new wire
 

fenderman

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its a digital signal, there would be no lines caused by interference...
 

pal251

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Busted cable then? I will try the loose patch cable idea.
 

pal251

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I believe it's LED lighting, its a brand new hotel. Not even open yet, here is a screenshot

It's a 2mp LTS IP camera. Tried it without and without the dome installed, same thing. Plug it into the switch with a 2 foot patch cable works fine
 

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alastairstevenson

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Plug it into the switch with a 2 foot patch cable works fine
Presumably it's away from the lights when connected like that.
Can you use a long patch cable and move it towards the normal location and observe the effect appearing?
 

pal251

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I can make a patch cable, doubt I can get one in time for the next time I travel there. I have one run that the electricans ran that is like 300 feet long next to the lights, no problems. I wonder if it's just a bad cable
 

Fastb

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Here's a hunch.

A guy showed me a trick. We were discussing fluorescent lighting, specifically magnetic versus electronic ballasts. He showed me how to determine the type of ballast being used by using the camera in his cell phone.

Looking at the camera image on his phone's screen, and aiming the cam directly at the fluorescent tube, the magnetic ballast caused black lines to appear on the tube. The electronic ballast didn't do this, and the tube appeared evenly lit.

That's a new hotel, so magnetic ballasts aren't used. However, you might use your cell phone cam to see if the dark lines are present. And you might narrow down which light fixture is responsible. This is a very simple and easy test to perform, and might yield some clues.

Another thought:
maybe those are dimmable lights, turning on and off with a varying duty cycle, to adjust the light level. If the lights are not set to 100% illumination, then they may be off part of the time, eg: 50/50 duty cycle

Good luck
Fastb
 

pal251

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Possibly. There is a lot of energy efficient stuff going on. I don't notice it as much during the day. You think a shielded cable would help?
 

fenderman

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Possibly. There is a lot of energy efficient stuff going on. I don't notice it as much during the day. You think a shielded cable would help?
It's got nothing to do with the cable... interference doesn't affect IP packets in that way...
 

Mike A.

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Might try changing the frequency of the cams if you can. As Fastb hinted at above, it looks like typical sync flicker with that of the lights (e.g., similar to the effect below). The LED lighting very likely will use some form of PWM and it may be matching that. That also would account for the effect not being present when you move it to try at the switch with different lighting there and less of an effect during the day.

e.g., Video using the same camera of 3 different LED lights with different modulation types/rates. Middle one causing the similar banding.


 
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