Interference/ghosting help

[MrPenguin 0]

I have an old condo building that had be upgrade their 4 camera video system. Basically, swap out B/W cameras for color, vcr for dvr, and change the location of the dvr. Everything is done, and it works, but occasionally there was ghosting on 2 cameras and still is horizontal lines/static for about 1/8 the height of the screen 1/7 the way from the top on 2 cameras and 1/7 the way up on the other 2. The static comes and goes totally randomly. At times it may stay and then get much worse where it suddenly encompasses the entire camera, but the proper picture eventually comes back. All of this without any user interaction. Sometimes it comes and goes within 20 seconds, other times longer. Totally random. The horizontal lines are always at the exact same locations when they appear. sometimes they roll or do other motion, but only within that same 1/8 section they are in, not rolling through the entire screen or getting bigger/smaller.

 

We originally had it where the cameras were powered by 24v plug in power supplies. When the ghosting appeared, you could unplug one of them and all ghosting on all cameras would go away, plug it back in and no ghosting for a while. One thought was ground issues. I redid all the ends taking extra care, the ghosting dropped almost to none (barely visible occasionally on one camera), but the static still comes. I have since changed over to an atronix 24v fused psu. With no change, other than now, unpluging does not change anything on the picture for static.

 

I have unplugged the DVR and had the cameras plugged directly into the tv, same issue. I have removed the UPS from the equation, same results.

 

My current thought is the power is not clean. It is a very old building and the UPS they have does not do line conditioning.

 

In relocating the DVR, I had to splice in a new section of cable to make it to the new location. I added about 30-60' or so of cable. In reading today, I saw that the RG6 I used for that extension may not have been the best choice. The existing wiring is RG59.

 

My plans currently are to get a conditioning UPS first. Try moving the PSU to the original dvr was. Lastly, and most avoidably would be to swap the new sections of cable.

 

So, any hints as to what to test/try first?

Would a line conditioning UPS help this issue?

The complete randomness of this issue is what really annoys, I cannot pinpoint the source.

 

DVR = Speco TN series

PSU = Atronix 24v

Cams = Toshiba IK-65wda

 

Thank you.

[Soundy 1]

Sounds like possible ground issues to me as well... with each camera on a separate transformer, however, it shouldn't be directly related to the power source.

 

One possibility is if the affected cameras are in grounded metal enclosures, giving them separate ground paths from the coax shields - unplugging one of the affected cameras and shutting it down would then eliminate the ground loop. Disconnecting one of the noisy cameras' video lines should also clear up the noise on the other.

 

The other possibility is that one or more of the lines run near a source of strong, randomly-occurring EMI... such as HVAC, an elevator, etc. See if you can correlate the noise to anything else turning on in the building.

[vitHoward 0]

You mentioned that you used RG6 cable. If the cable is copper covered steel center and foiled shielded, that might be your problem. It doesn't matter whether it is RG59 or RG6 as the RG number simply specifies the size. It's the construction of the cable that matters.

 

Foil shielded cable allows the composite video to create "waves" that can cause ghosting. I had an 18" jumper in the middle of a 300 run that completely messed up my signal. It took weeks to find it.

 

Look at the surface of the cable jacket. If you can see the "herringbone" pattern, it's the wrong stuff.

 

Please post a reply to let me know if that's the problem.

Howard