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Tips To Fix Fuzzy Surveillance Video - April 20, 2011

Tips To Fix Fuzzy Surveillance Video - April 20, 2011

Tips To Fix Fuzzy Surveillance Video
By Christian M Gillman

Finally get your surveillance system all set up only to find you have a picture distorted with lines or tearing? Before you find yourself writing an angry letter to your surveillance installer or dealer; know this. Most likely what you are experiencing is known as ground loop interference. This is a problem that is hard to anticipate and most likely is nobody's fault; at least not directly. Never fear however; because it can be corrected, and this will show you how.

What Is A Ground Loop? How Is It Caused?

First of all a ground loop is a type of electrical interference. It occurs when the AC current present in the system interferes with the ground level video signal. This interference happens along the conductive path formed by the shield of your cctv video cable and the chassis of your video equipment. When this happens there is a difference created between the voltage potential of the shield at each end of the cable. Normally the electrical level of a cctv video cable shield is 0 volts; however when a ground loop is present it fluctuates above and below this level, which in turn creates the distortion you are seeing. As this difference becomes greater it causes more severe distortion, and can in fact destroy your surveillance equipment if the difference becomes too great.

How To Fix It

It is always a good idea for a dealer, installer, and customer to know that a ground loop can potentially occur in their surveillance system, because it allows the budget to be adjusted for a ground loop isolator if needed. What a ground loop isolator does is reduce the difference levels occurring in your cctv cables and eliminate your video distortion. These devices are typically passive devices that can be installed without the need for a power source and they are quickly added to any existing surveillance system (15-GL01).

It should be noted that this problem can occur at multiple points throughout a surveillance system and that a ground loop isolator will be needed for each area it is occurring.

In the end this is a problem that should be talked about when buying a surveillance system; however as it cannot really be predicted as to whether it will occur or not; you can only wait until the system is installed to find out. Ground loops can arise in a variety of connections; such as from your cameras to your monitor, your cameras to a switcher, or many other possibilities; so trying to anticipate the scenario is rather difficult. By allowing a small section in your budget for this problem you can save yourself time, money, and stress when it comes time to resolve it.

Christian M Gillman has worked in the surveillance industry for over 6 years. Subscribe to our monthly newsletter, learn more about surveillance, and find great products at

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