Diagonal Lines... RF Interference?

[MillerTime 0]

Has anyone experienced diagonal lines on installed cameras?

 

We have installed a CCTV system in a building right next to a AM radio station. We have about 13 cameras on the system the diagonal lines are visible in all of the cameras but get worse with the longer runs. The worst being the long runs that we used baluns. The runs are approximately 400ft with passive baluns.

 

Do you think that the radio station could cause this problem?? Any ideas on how to fix it would be appreciated.

 

I have a picture of it I can send or link to later tonight.

[dvrtiger 0]

I don't think that radio frequencies are cause of your problem, especially on coax lines and in buildings with fine protective ground in power junction box... did you try to test cameras, one by one, connecting them to the monitor?Did you try another monitor? More likely one of the cameras or baluns is causing it. RF usually produces fast horizontal lines or flickering effect on monitor, depending on frequency. And electronic circuits of cctv equipment are shielded from such problems (or cctv would never function in shops with eas system installed, which is also RF or AM based).

[survtech 0]

If the interference is from the AM radio station, more than likely you would be able to see the modulation of the signal. It would probably appear as a change in the pattern of the interference with the varying volume of the signal. Try tuning the station in on an AM radio while watching a camera and see if there is any correlation between the interference and the sound.

[mitstarion 0]

I have saw diagonal interference before and the culprit is the wire connecting the DVR and Monitor.

[zmxtech 0]

most AM and FM stations dont have the transmitter near, there linked by landline or microwave many Km away ?

 

but if your one is... sounds like it for sure ! I would grab a CRO and look at the waveform

 

Some Ferrite chokes everywhere might fix

 

z