meyerside

I hope someone can help me. We have an installation of PTZ camera over 200m distance using RG-6 coax cable (one continuous wire). The video has horizontal shift & induces tearing on the top of the screen. These horizontal shifting does not roll over the screen. We thought it was a ground loop problem and installed ground loop isolator on RX side, TX side and both, but to no avail. Upon careful examination of the video, we found that the tearing only happens when we are looking at bright object (i.e. sky). When we move the PTZ to look at dark object (i.e. ground pavement), then the tearing artefact goes away. As such, at night time, we see the tearing artefact less than compared to day time. Any ideas? It could still be ground issue as we measured 6Vac between BNC shield and our DVR ground. After installing Ground loop isolator, this value went down to 0.5Vac, but as stated earlier video did not improve. Any help or guidance would be appreciated.

I don't know if this helps or not. We are also using Pelco IWM24-GY PTZ arm which has built in transformer and accepts 120VAC directly.

The brand of camera is Pelco Spectra IV PTZ The display we are using is LCD monitor - refresh rate of 60Hz.

Thank you for the replies. First - Yes, the coax is properly terminated with 75 ohms. It's going to a DVR and we switched the cable to known good channel, but the problem follows the camera. Second - as for cable. All I know is that it's made by "provo". I will try to find the model number.