The GB474PTZ Ground-Loop Blocker is an active device used to eliminate Ground Loop Interference and picture quality problems in new and existing CCTV video installations. This product will allow "Up the coax Remote Control Pan, Tilt, and Zoom" operation and will extend the range of the control signal up to 3500 feet. The unit is installed at the monitor site where the CCTV signals come together, or at any intermediate point where video ground-loop problems exist.
The GB474PTZ operates with any standard B/W or Color video signal. This device controls and corrects four channels of CCTV video. Each channel is separately adjustable for Video Level and Picture Sharpness. A built-in active ground loop blocker removes the 60 Cycle Bars from the CCTV signal even after they have become part of the video signal and prevent 60 Cycle "Hum Bars", restore the video level, picture sharpness, and allow PTZ control signals to pass up the coax cable for control of your camera. The Level control can be adjusted to overcome losses due to long cable runs up to 3500 feet, poor cable quality, and improper video terminations.
The Picture Sharpness control can be used to restore Picture quality to its original sharpness due to long cable runs, poor quality coaxial cable, kinked or damaged coaxial cable or twisted pair "Balun" transmission installations. It restores the video color-burst on a color camera to improve color camera operation on long cable runs and prevent Ghosting in the picture by absorbing and eliminating the reflected video Ghost signal. In addition, it will restore the Characteristic Impedance of the down stream video signal to prevent secondary Ghosting in the picture.
By installing the GB474PTZ in your existing CCTV system you can avoid the many hours of troubleshooting and trial/error associated with problem installations. For some installations you will find it advantageous to install a GB474 on each group of four channels. It is especially useful in installations requiring lightning protection. Lightening protection devices often induce 60 cycle bars into the video signal because they use a connection to ground that does not equal the video ground at the monitor point