School Installation

[alanb 0]

We are installing a DVR system into a high school. Because of the size of the school we need to use two separate power supplies. The first supply has 8 cameras on it and they all work fine. The second supply is located in another wing of the school. It has four cameras on it: A PTZ, a dome, and two bullets. For these four cameras we ran Cat 5 using MuxLab baluns. The PTZ is using the PTZ balun and the other three are on a 4 channel video hub balun such that a single CAT 5 can be used for all three video signals. Separate power gets run to all of them.

 

 

At first all four cameras had rolling bars on them. If we disconnected the PTZ, the other three cameras would then work fine. If we reconnected the PTZ and disconnected the video hub balun, then the PTZ would work. During troubleshooting, we saw that the PTZ was not grounded so we ran a separate ground wire and now the PTZ picture works. (We have no PTZ RS-485 control of the PTZ using the balun). However, when we now disconnect the PTZ the other three cameras still have rolling bars.

 

The three camersa are all mounted to brick. When we connect our handheld LCD monitor right at the camera the picture is fine. These CAT5 runs are around 500 to 600 feet, the PTZ is 800 ft. Should ground wires be added to these cameras? Beacuse the handheld works I am not certain the problem is related to the power supply. Any suggestions????

 

Also, I would appreciate any tips for getting the control line of the PTZ to work. Naturally, the PTZ/DVR worked fine at our shop using the PTZ balun before we installed it . We check polarity and all the obvious things.

 

Any help is certainly appreciated.

 

Alan

[VST_Man 1]

sounds like ground loop. you either need ground loop isolators or active baluns, not passive. ground loops are tough to fix when you apply basic grounding techniques, power schemes. best way to avoid ground loop or poor video picture is to use active baluns from the start. I learn that the expensive way.............hard way.

 

PTZ? If it works on a short wire then you already have your answer.........that wire run is too long for the signal to go OR you have interferance on the wire. make sure all your cable runs are not installed close to ac power cables.

 

ground loops are created when you have differences in poientials. That potiential can sometimes be solved by grounding but I've found that it is very hard to get right because when you fix one camera the others go bad? no ryme or reasn other than that potiential shifted and your chasing it. ground loop isolators block those unneeded signals and allow the video.

 

good luck

[DataAve 0]

baluns?

[Doug 0]

I've seen this on several occasions using passive baluns and DVRs, it can normally be resolved by using independant power supplies for each camera.

 

Try using four plug in transformers on a power strip instead of the multi camera power supply.

 

If that doesn't work then try using active baluns at the head end.

 

Doug

 

 

We are installing a DVR system into a high school. Because of the size of the school we need to use two separate power supplies. The first supply has 8 cameras on it and they all work fine. The second supply is located in another wing of the school. It has four cameras on it: A PTZ, a dome, and two bullets. For these four cameras we ran Cat 5 using MuxLab baluns. The PTZ is using the PTZ balun and the other three are on a 4 channel video hub balun such that a single CAT 5 can be used for all three video signals. Separate power gets run to all of them.

 

 

At first all four cameras had rolling bars on them. If we disconnected the PTZ, the other three cameras would then work fine. If we reconnected the PTZ and disconnected the video hub balun, then the PTZ would work. During troubleshooting, we saw that the PTZ was not grounded so we ran a separate ground wire and now the PTZ picture works. (We have no PTZ RS-485 control of the PTZ using the balun). However, when we now disconnect the PTZ the other three cameras still have rolling bars.

 

The three camersa are all mounted to brick. When we connect our handheld LCD monitor right at the camera the picture is fine. These CAT5 runs are around 500 to 600 feet, the PTZ is 800 ft. Should ground wires be added to these cameras? Beacuse the handheld works I am not certain the problem is related to the power supply. Any suggestions????

 

Also, I would appreciate any tips for getting the control line of the PTZ to work. Naturally, the PTZ/DVR worked fine at our shop using the PTZ balun before we installed it . We check polarity and all the obvious things.

 

Any help is certainly appreciated.

 

Alan

[alanb 0]

Doug:

We put the cameras on separate transformers and like magic everything is now working perfectly. Thanks!

 

I appreciate the tips offered by all members.

 

Alan