Centralized Power Supply Problem

[gmartz 0]

Hi!

 

So we're having a problem when using centralized power supply. Here's the system (residential installation btw):

 

6x Analog 700TVL (960H) Cameras DC 12V

1x 8-channel (Hikvision) Turbo HD DVR

1x 18-channel Centralized Power Supply box (individually fused)

 

Cable wire used: cat5e UTP (with video baluns on both ends for the cameras)

 

Cable runs are just around 10 to 60 meters (max). What happens is, upon plugging in the cameras to the centralized power supply, we experience interference on the screen (those wavy black bars). When only one camera is connected, it's fine but the more you add cameras, interference kicks in.

 

On the other hand, when we use individual adapters (12V/1A), no interference experienced.

 

Will there be a difference if we use a lesser channel Centralized Power Supply box (maybe the 8-channel one) since we only have 6 cameras installed? Lastly, if it says "individually fused" does it mean the power distribution is equal even though we're only using 6 channels out of 18? We're thinking that the box s giving more power to the cameras since it only has 6 connected.

[mattaggie 0]

I doubt power supply is the problem. Its not "overpowering" the cameras. Each connection is for the right voltage.

 

Since you are using Cat5, its probably an electrical issue that has to do with power and video going through same cable. The power ground signal is interfering with video ground signal. Try a video ground loop isolator and see if that doesn't solve it.

[aibudo 0]

I agree on ground loop. There are differences in video balun adapters. Some are not the best.

[almelst 1]

Is any of cameras fixed on metal grounded surface, like a pole or something ? In that case, the problem is ground potential difference between camera and DVR, which causes signal interference. Camera housing is internally directly connected to signal ground and power supply minus pole. Solution? Isolate camera from metal surface (including screws, too) or use ground loop isolator video balun.