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Light horizontal scrolling lines


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#1 jeffx

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Posted 21 September 2005 - 08:12 AM

I just rewired two CCTV cameras using RG6, and the picture quality is actually not as good as when I was just running the cameras over phone wire (CAT3).

What will cause light scrolling horizontal lines? I was careful not to run the RG6 anywhere near 110V lines. I even shut the power off to that side of the house and ran my PC/cameras off of UPS power and still had the same line artifacts.

Both cameras are being powered off of the same power supply (could this be causing the problem?)

I have two other cameras going to the same DVR card (the famouse eBay 240 FPS card) without lines, but these run over RCA cables and each have their own power supply.

All comments/suggestions would be helpful!

Here is the total path from the camera to the capture card:

Camera with BNC output
"F" FEMALE TO BNC MALE ADAPTOR
"F" MALE TWIST-ON FOR RG-6
RG-6/U COAXIAL CABLE ~ 60 Feet
"F" MALE TWIST-ON FOR RG-6
F connector with plastic insert
"F" MALE TWIST-ON FOR RG-6
RG-6/U COAXIAL CABLE 6 Feet
"F" MALE TWIST-ON FOR RG-6
"F" FEMALE TO BNC MALE ADAPTOR
Capture card with BNC input

Edited by jeffx, 21 September 2005 - 08:13 AM.


#2 tech-home

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Posted 21 September 2005 - 08:24 AM

"F" MALE TWIST-ON FOR RG-6

The twist on connectors are not known to be very good quaility. I used these for a few and switched over the snap on version with much better results. Yeah the tool wasn't cheap though.

Also are you sure you terminated the rj6 correctly?

http://www.hometech....n/coaxterm.html

Edited by BrianD, 21 September 2005 - 08:31 AM.


#3 Chas821

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Posted 21 September 2005 - 10:07 AM

The scrolling horizontal bars in the video indicates that there is a 60 HZ AC component in the video. Change out the camera power supply as I suspect it's not well filtered. The clue here was that the other cameras each had their own power supplies. Filtering a power supply that's not heavily loaded isn't that hard, but heavily loading one power supply (I'm assuming here that they are wall warts?) with the two cameras is breaking down the filtering.

Doing CCTV without a decent power source (a switching power supply) is asking for the trouble you're experiencing.

Chuck

Edited by Chas821, 21 September 2005 - 10:12 AM.


#4 BraveSirRobbin

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Posted 21 September 2005 - 10:11 AM

Also, do a quick check and measure the resistance between the coax (with both ends not connected to anything) center conductor and ground to make sure you don't have anything shorted (loose braid against ground or a bad crimp/twist when installing the connector. If you need help with this let me know.

#5 jeffx

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Posted 21 September 2005 - 12:09 PM

I'm assuming here that they are wall warts?


Here is the power supply I am using. It is 2 AMP and the cameras only use 220 mA max each w/ IR on. Before I re-wired from CAT3 to RG6, using the same power supply, I did not have the scrolling lines problem (but there was a pretty visible shadow which prompted me to go to the RG6).

I found a 12V 300 mA power supply lying around the house and I will put that on one of the cameras to see if that helps, though.

The twist on connectors are not known to be very good quaility.


I was questioning with the twist on "F" connectors how they could get a good connection to the ground as I was installing (and I appear to have been correct to question this), so I'm goint to replace those also. I just put in an order for compression tool, a better stripper (my stripper appeared to be cutting into the groun foil) and a bag of compression fittings.

Also, do a quick check and measure the resistance between the coax (with both ends not connected to anything) center conductor and ground to make sure you don't have anything shorted (loose braid against ground or a bad crimp/twist when installing the connector. If you need help with this let me know.


I'll check the resistance between the ground and center conductor after I put the compression tips on.

Thanks to all for the assistance! Parts Express is always fast to ship, so I should be able to work on these fixes Friday or Saturday.

#6 jeffx

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Posted 21 September 2005 - 07:57 PM

Is 4 inches too close to a power outlet for my RG6 wall plate (where my camera connections terminate)? I'm thinking now that the nearby outlet may also be a source of 60 Hz noise, even though it is only affecting 2 of 4 cameras.

If so, how far away should I move the outlet from the video wall plate? I can always put another 2 gang data wallplate in it's place and moving the electrical is fairly quick and easy.

Just trying to eliminate every possible cause of noise while I am re-doing these connections...

#7 tech-home

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Posted 22 September 2005 - 01:10 AM

Is 4 inches too close to a power outlet for my RG6 wall plate (where my camera connections terminate)? I'm thinking now that the nearby outlet may also be a source of 60 Hz noise, even though it is only affecting 2 of 4 cameras.

If so, how far away should I move the outlet from the video wall plate? I can always put another 2 gang data wallplate in it's place and moving the electrical is fairly quick and easy.

Just trying to eliminate every possible cause of noise while I am re-doing these connections...

18 inches is what is recommended.


I do have some closer but they are seperated by a stud and I haven't noticed any issues.

#8 Squintz

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Posted 22 September 2005 - 06:21 AM

Lines to me usually means a horizontal or vertical sycning issue. Just to give you a reason why I think that....

My ex's parents gave me a large tv that was only a year old but it had horizontal lines that were faint and scrolled slowly. They were on a slant and not perfectly horiontal. To fix it I opened up the TV and there are two potentiometers just behind the conveer. I adjusted one and it made the lines go away. Those potentiometers control the horizontal and vertical syncing.

So your camera could be proving a signal that is not matching up with the display. You can try to find out why its not the same by fixing the camera or you can adjust the display to match the camera.

#9 jeffx

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Posted 30 September 2005 - 09:46 AM

just a quick update. I replaced the ends of all my coax cables with the higher quality compression tips and this seemed to clean up any shadowing, but the horizontal scrolling lines are still there. Moving the cables around in my smart closet has a pretty big affect on how bad these lines are, so I'm pretty certain this is being caused because I have my camera/coax wallplate to close to my electrical outlet.

I'm hoping I'll have the time to move the outlet to another wall in the closet this weekend so I can resolve this issue.

#10 jeffx

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Posted 03 October 2005 - 02:17 PM

moved the outlet this weekend, still getting the horizontal lines. Should I have each camera on a separate power supply?? Could the fact that 3 cameras are sharing one (regulated 2 AMP 12v) power supply be the issue? or maybe the way I have them wired?

The 12v pairs from each camera terminate at one + and one - post. From this post, one wire from both the + and - goes to the + and - on the power supply. When I had only one camera setup, I did not notice these lines. Having some family over to work on my roof tonight (two electrical engineers) and I am going to seek their advice also.

#11 Squintz

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Posted 03 October 2005 - 02:29 PM

When you plug the TV into normal cable television do you still get the lines? I guess my question is; Is it the TV causing the problems or is it the Cameras and/or cables. If you read my post before it sounds a lot like horizontal syncing.

#12 rocco

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Posted 03 October 2005 - 06:04 PM

Jeff, can you post a picture?

I've hesitated to consider possible causes because I don't know if "horizontal scrolling lines" means horizontal lines that are scrolling (vertically) or lines (vertical or diagonal) that are scrolling horizontally. And by light, do you mean that they are hard to see? or that they are brighter then the rest of the picture? Also, are they sharp-edged? or do the fade off gradually?

I can diagnose many image problems if I can see them.

Edited by rocco, 03 October 2005 - 06:05 PM.


#13 jeffx

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Posted 06 October 2005 - 03:09 PM

Jeff, can you post a picture?

I've hesitated to consider possible causes because I don't know if "horizontal scrolling lines" means horizontal lines that are scrolling (vertically) or lines (vertical or diagonal) that are scrolling horizontally. And by light, do you mean that they are hard to see? or that they are brighter then the rest of the picture? Also, are they sharp-edged? or do the fade off gradually?

I can diagnose many image problems if I can see them.

Horizontal scrolling vertically, light as in brighter than the rest of the picture (most noticeable in low light conditions). Fade off gradually, hard to see in still captures, but easily noticed in video.

I'm going to try a different power supply tonight (found a 12v 1.2 amp wall wart that can power all 3 cameras).

Here are "live" captures"

Posted Image
Posted Image
Posted Image

#14 WayneW

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Posted 06 October 2005 - 03:13 PM

Are those the $65 cameras from Direct Sales?

#15 jeffx

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Posted 07 October 2005 - 11:08 AM

Are those the $65 cameras from Direct Sales?

Yes, the above captures are from the $65 Direct Sales cameras.

I tried a different power supply last night, but I'm still getting the horzontal banding that scrolls vertically. I tested each of these cameras individually directly to a monitor before installing them into their current locations and the picture had no defects.

I'm now beginning to believe that the line noise is either being caused by the PC or the capture card (or both). So to troubleshoot further this weekend, I am going to patch the cameras directly to a monitor, patch to a different capture card in another PC and install the 8 port card in another PC to see if the banding is eliminated in any of those scenarios. Wish me luck.




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