WZ16 camera and rainbow color noise

I was looking for a weather-resistant bullet camera (or dome) with a 4-9mm lens, auto iris, >=480 TVL resolution and better than 0.1 lux sensitivity, to monitor a ~30x30' courtyard. The camera is under a small roof, so not completely exposed to elements and, due to space consideration, I cannot use a box-style camera with an outdoor housing.

I ended up getting a WZ16 camera, even if I didn't necessarily need the built-in IR (especially because it tends to cause lot of motion detection at night, and I have enough illumination in the courtyard to get by without IR).

The camera works well in day mode. When in night mode (and you can see the IR LED coming on, and the mechanical IR filter click in place), the image shows pretty bad rainbows (see picture in the attached file, also available )

The image is perfect when in daylight mode, and perfect when in full IR (no other light source). In night mode, any source of non-IR light causes the rainbows.

Where it gets weird, is that the problem only appears with DVR cards (I tried 2, one a GeoVision, one a cheap clone, which has much worse issues, and the one used for the picture). If you connect the camera directly to a monitor, it shows a normal B/W image in night mode

Ian at ExtremeCCTV has been great and tried to pinpoint the problem, to no avail. The dealer even sent out a new camera (thanks to ExtremeCCTV advance replacement warranty), but the problem is still present (alas, the new camera serial number is only 8 units away from the previous one: I was hoping to get one from a different batch)

Given I'm having the problem on 2 completely different DVRs (and those work just fine with many other day/night cameras), I have a hard time accepting the fact that the cameras "work as expected", even if they show fine on a monitor (that monitor can display pretty much anything with a pulse ).

I saw similar problems on this forum with a KT&C camera, and in that case the manufacturer found a manufacturing problem that caused the issue.

At this point, I'm inclined to return the camera (unless anyone here has a suggestion). Did anyone else saw rainbow problems? How was the problem solved?

Any suggestions on what to buy instead? No IR, if possible, to avoid all the IR issues (insects, false alarms, etc). Specs as at the beginning of the post

Following up on my question. Any opinions on the Weldex cameras, esp. model WDBAC-3585C? http://www.weldex.com/index.cgi?m=catalogue;t=1;c=5;i=58

Is there any day/night bullet camera (i.e. switching to low-light B/W mode when needed) without integrated IR?

I think I found a camera that works for me, so that part of the question is not relevant anymore.

Just curious, though: has anyone else seen rainbow problems on Geovision DVRs with WZ-16 cameras? As a matter of fact, has anyone every tried a WZ16 with a Geovision DVR card?

No, ive used the WZ18 on the Geo without those particular problems, though there were other camera related issues, do a search on the forum for Wizkid

just a guess, but it might be an impedance mismatch between the camera and dvr card that isn't occuring when you connect directly to a monitor? perhaps the camera needs a close 75-ohm match to the feedline in order for the day/night switching function to operate properly? how is the line terminated?

It is not a day/night thing, it appears to be a color/bw thing. I've seen that symptom before - many years ago. It used to happen on tube-type color TV's. The 3.58MHz color reference frequency oscillator would go out of lock causing almost exactly the same symptoms.

Damned if I know what the cause is, but I would guess that the camera is sending a B/W signal but the ACK (automatic color killer) on the DVR card is not engaging. Can you attach an oscilloscope? A color signal looks like this:

.

A normal B/W signal should look similar but without the color burst signal. My guess is that something is missing. Most likely is that there is color information coming from somewhere without the burst signal. I don't know where.

marzsit: I tried different types of RG59, RG6, Cat5 with good quality baluns, and direct connect to the card... hard to imagine it was the cable (but very valid point)

Survtech: I have a scope at home (currently traveling). Will hook it up and check. Good idea. I have another day/night camera connected to the same DVR, and it switches just fine to B/W mode, so I can compare the 2 signals

My bad, it was the WZ16 i guess we have here .. it was the 4-9mm version .. unless they changed the model .. either way, they are sitting in my colleagues garage as the day night switch over would never stay focused, no matter when or how it was focused .. We use a similar camera to the WZ16 now, but at almost half the cost, and it stays in focus between day and night modes.

To close the loop on this, I tried the WZ-16 camera with a Techwell-based chipset (DiViS) and it works pretty well both in day and night mode. There seems to be a problem with the BT878 chips, as far as I can tell