Coaxial Cameras Testing Voltage

Validating Power:

One of the first steps with troubleshooting coaxial based cameras is to verify the camera is receiving appropriate power. If there are issues with power, cameras will not be able to reliably transport video. The most surefire way to rule out an environmental issue, i.e. power or interference, is to connect the cameras on a short, sandboxed cable run. In other words, you would place the camera in close proximity to the video recorder and connect it to the system with a new coax cable and a direct power supply. If you have video, the issue lies with the environment. This guide will help you determine potential issues with power transmission.

Using a Multimeter:

You can use a multimeter to determine if the power distribution box is outputting enough power. Most distribution boxes will have a positive and a negative terminal to which you can touch the multimeter probes to. Most systems will either read 12VDC or 24VAC. Check the specifications on your particular power distribution box. If you are getting no power or less than what the power supply is supposed to output, you may have a faulty distribution box.

Factoring in Distance:

Power distance plays a heavy factor in video transmission. Voltage will inherently drop over distance. If your power cable is running a significant distance, you may not be supplying enough voltage at the end of the run to reliably keep the camera powered. Fortunately, there are voltage drop calculators that can be used for these very reasons.

You can increase the voltage to compensate for longer runs. For example, if you have 12VDC 2A power running 150ft, you may drop up to 31% of the original voltage by the time it reaches the camera. You would need to increase the voltage by an equal amount so you still have 12V by the end of the cable run.