I have an analog license plate camera KT&C, KPC-LP850NH which has been giving me problems for some time now. I installed it last November on an exterior wall of our building. This is in southern California where it doesn't get too hot or cold. The power supply is a 12V ~2A and connected to an outlet right next to the camera's location on the inside of the wall. It is connected to a Vivotek VS8401 encoder which is connected to a Windows 7 computer running ExacqVision. Up until a couple of months ago, the camera was working flawlessly. Lately, however the video signal is cutting in and out intermittently. At first, the picture would flicker a little during the morning at around 10am-11am and then restore itself. This would also happen late at night, around midnight. Then I started getting "Video Loss" and a blue screen on that channel. That typically happened at the same times and would eventually restore itself. The amount of time the channel was down kept increasing until it could be down most of the day.
I've tried a few things to figure out what the problem is. When I first started having the problem, disconnecting the power supply and reconnecting would make the problem go away for a bit. If I left it unpowered for a whole day, the problem went away for a longer time, maybe a few days. I hooked up an outlet timer to shut it off each day for thirty minutes at a time of day when some overlapping cameras are able to reliably pick up plates, but eventually cutting the power didn't seem to be effective. I had a ground loop isolator attached, which I removed because it seemed to have caused a problem with another camera previously. I thought that had fixed the problem at first, but it came back. I switched from using a coaxial cable (about 150 ft worth or so) to a CAT5 with these video baluns which I used with about 15 other cameras without a problem. I still have the issue. At first, if I disconnected the video cable at the camera and then reconnected it, the problem would clear up for a bit. Now that doesn't seem to work, but if I disconnect the video cable at the encoder and reconnect, the problem goes away immediately.
Vivotek recommended I tried moving the camera to a different channel on the encoder to see if there was a hardware problem. I did that yesterday, and within twelve hours or so, the camera started having problems on the new channel, while the camera I moved to the LPC's old channel had no problems.
This is starting to drive me nuts. The camera is great- I've got it tuned in to pick up almost every plate on vehicles going up and down the main approach to our building- but I've got to get this figured out. Has anyone had a problem like this or have any ideas? Thanks in advance.