Colour interference problem

[Sloper 0]

I've had my 4-channel Avtech KD674 DVR up and running with a single camera for about a week now, without problem. However, yesterday I added a second camera, and while everything is fine during daylight hours, after dark, when the IR LEDs are on, I'm getting colour interference on the screen from one of the cameras. It comes in bursts that last a second or so and always every 8 to 10 seconds. It sees this as motion so I've had to disable motion detection for now.

 

If I disconnect power to the other camera, then the interference stops Both cameras are on a single 2amp power supply (using a 4-way splitter), which should be more than enough, according to each camera's ratings.

 

Could anyone suggest what might be causing this?

[rory 0]

maybe try switching the cameras around, if the problem camera is say camera 3 then move it to camera 1 instead.

[Sloper 0]

maybe try switching the cameras around, if the problem camera is say camera 3 then move it to camera 1 instead.

 

I've tried swapping the two camera's channels, and also tried the offending camera on the two spare channels. I've also tried using the two cameras on different power supplies but the fault remains

 

Think it's a faulty camera then? I wonder if the retailer will accept it is faulty if it's ok when I disconnect the other camera.

 

Anyway, cheers Rory.

[Sloper 0]

No further suggestions?

 

I'm at a loss. It looks to me like the problem may be with my DVR. Would you agree?

[Birdman Adam 0]

EDIT: Oh crap, i just noticed you already tried new power supplies...

In that case I guess that second camera you got must be the problem...

 

I think your power supply must be at fault.

 

Either it can't handle the cameras at night when the IR turns on, or there is some sort of loop problem.

 

Either getting a bigger power supply or getting a separate one for each camera may fix it.

[rory 0]

try to power each camera on its own individual power supply and see if that makes a difference. Does this occur when you connect just one camera to the DVR at a time?

[Sloper 0]

I have already powered each camera on individual power supplies. I'm tempted to think the second camera is the problem, but then why is it ok when I disconnect the other camera?

 

Could the DVR have some problem? It's been suggested to me that a termination circuit within my DVR is faulty and the one camera signal is causing interference on the other. I have no clue about these things.

 

I'm going to order a third camera today ( I was going to get one eventually anyway). Hopefully, that should narrow the problem down.

 

Thanks for the replies guys.

[Birdman Adam 0]

Yea, I mean we've pretty much ruled out power supplies, and the cameras.

 

All that's left is the DVR

[Sloper 0]

Well, the new camera arrived today. I've just connected it up and it produces a good IR image; good and steady... BUT, with three cameras connected, the image from the suspect camera has now become even worse. There are stronger bursts of colour noise then before.

 

I've tried running all combinations of two of the three cameras and it's always the image from that one particular camera that has the problem (run on it's own, its image is fine )

 

So, it looks like the camera is at fault, not the DVR ( I think!)

[rory 0]

is the problem camera a color or BW camera? If it is BW try turning the saturation down on that channel? Just an idea, cant promise it will work

[tomcctv 187]

Well, the new camera arrived today. I've just connected it up and it produces a good IR image; good and steady... BUT, with three cameras connected, the image from the suspect camera has now become even worse. There are stronger bursts of colour noise then before.

 

I've tried running all combinations of two of the three cameras and it's always the image from that one particular camera that has the problem (run on it's own, its image is fine )

 

So, it looks like the camera is at fault, not the DVR ( I think!)

 

 

i have seen this before. try and turn the power around red to - and black to +

[Sloper 0]

Jeez, this is turning into a bit of a saga.

 

The image from my new camera is now doing exactly what the previous camera's image was doing - lots of colour noise in fairly regularly spaced bursts.

 

Last night, when I tried out the new camera, it was fine, as I mentioned in my previous post. However, I had only connected it up to a spare cable temporarily, and hung it out of the window to test it. Now, it is properly installed outside and connected to the cable I installed originally with the previous suspect camera. So, it looks like that cable is the problem! What do you reckon? Could perhaps a badly made-up cable cause this.. maybe a poor power or signal connection?

 

There is one other possibility that occurred to us. There is an old phone line outside, fitted to the wall close to the camera. The line isn't in use now, but I think it's still 'live'. I think they carry 50 volts if I remember right.

 

Anyway, I'll be replacing that cable with a new one tomorrow. I'll report back!

[Sloper 0]

Ok, I changed the cable for a known good one today, and STILL have the problem! I have tried different cameras in that location and also different cables. I've tried swapping the channels around too, no change. As soon as the image turns b&w, there are bursts of colour noise.

 

It's always one particular view that has the problem, regardless of which camera I mount there, or which cable I use, so the problem has to be with the location of the camera (under the soffit). There's an old phone-line attached to the house just a foot or so from the camera, but the cable is not in the camera's view.

 

Got to get that cable removed.

[themerchant 0]

is the camera bracket touching any metal in that location?

 

what kind of cable is it? premade RCA or coaxial? it maybe something in the attic (high voltage wires, always cross at right angles)

Premade RCA cable is not so good and has no shielding.

 

 

 

I once had a problem with metallic reflective paper on a warehouse ceiling, which cause some weird issues.

[Birdman Adam 0]

So it's been narrowed down to where the cable has been run!

When you tested the spot with new cable, did you run it in a similar fashion as the old cable?

 

What kind of cable is this; Siamese RG-59?, Cat5?, RG-59 with 18/2?

 

What other wires of any type are within a foot of this cable as it makes it's way from the camera to the DVR?

 

MUST be some type of interference which only the B/W signal is susceptible to!

[Sloper 0]

Well I had the phone cable removed.. no change!

 

I got a replacement DVR box yesterday. Connected it all up and waited for dark with trepidation. I was optimistic though...

My hopes were dashed. The problem remains exactly the same, so I can discount the DVR at least.

 

In the attic, the only other wires are to the lights in the bedroom ceilings. We've tried switching power off to that lighting circuit completely, but the problem was still there.

 

Things are a bit better now but we're not sure what we've done to make the improvement. We have just 2 cameras running at the moment, and after dark they are fine until there is movement, and then the pictures go a little haywire for a couple of seconds before settling again. If I connect a third camera, the pictures from the first two go completely haywire and remain that way until I disconnect it.

 

I'm about resigned to only being able to use 2 cameras and not being able to have the audible motion-alarm switched on.

 

Adam, the cables are all siamese RG59. All ready made-up. Two no-name ones purchased on eBay and advertised as shielded, and the other is by Sentient, also sheilded.

 

One thing though... there's a PIR security light on the front of the house where the 2 cameras are. Is it possible that it could cause problems?

[themerchant 0]

Im thinking you might have a power supply issue. since it only happens at night, thats when the camera uses more power since the LEDs are on. also you indicated that more than 2 cameras, you have a problem. It would probably be best to have a power supply box rated to at least 5-10 amps or at least individual power supplies (instead of a splitter)

[erk 0]

Please tell me how you got on with this. I have exactly the same issue, with the same DVR. Each camera used individually works fine, but together 1 camera always has colour interference sliding across the screen, almost a shadow of another camera. I have tried them all oon the same psu, and using various different inputs, but to no avail. Also the cameras with a 4 way swann guardian usb and pc had the same issue, in fact it just would not show the image and used to flag up an alarm. My next step is to try using different cabling instead, to see if that sorts it out.