Right I have an analogue CCTV system comprising of 8 cameras.<Remainder read then snipped>
We'll number them as Cam 1 to Cam 8 to help with describing the problem.
They are all powered with 12 V dc from a proper CCTV power cabinet: https://www.tlc-direct.co.uk/Products/TSPSU16slash20.html which is next
to a 8 channel Samsung SRD870DC DVR.
The cable used is this: https://cpc.farnell.com/pro-power/ca-sel-07m100/security-cable-black-100m/dp/CB02516?st=CCTV
So the yellow co-axial is used for video and the red and black wires
used for 12V DC. There is an outer foil screen on the CCTV cable.
On 06/01/2022 17:43, SH wrote:
Right I have an analogue CCTV system comprising of 8 cameras.
Crosstalk via the camera PSU? Try powering a cam that is giving
crosstalk from a battery.
Bill
Right I have an analogue CCTV system comprising of 8 cameras.
Right I have an analogue CCTV system comprising of 8 cameras.
We'll number them as Cam 1 to Cam 8 to help with describing the problem.
They are all powered with 12 V dc from a proper CCTV power cabinet: https://www.tlc-direct.co.uk/Products/TSPSU16slash20.html which is next to
a 8 channel Samsung SRD870DC DVR.
The cable used is this: https://cpc.farnell.com/pro-power/ca-sel-07m100/security-cable-black-100m/dp/CB02516?st=CCTV
So the yellow co-axial is used for video and the red and black wires used
for 12V DC. There is an outer foil screen on the CCTV cable.
Now Cam 1 and cam 2 are at the front of the house.
Cam 8 is at the back of the house. Their respective cables run for about a metre before cam 8's cable branches away from the cables for Cam 1 & cam
2.
Cam 1 is looking at the front lawn.
Cam 2 is looking at a car with alloy wheels on the front driveway
Cam 8 is looking at a vegetable patch in the back garden which has a
picket fence around it.
On the TV sets when selecting Cam 1, I am seeing a horizontal scrolling
ghost image of cam 8 on here it looks like a grey pencil drawing of all
the edges of of the slats of the picket fence slats across what is the
front lawn.
So something from Cam 8 is getting into Cam 1
On the TV sets when selecting Cam 8, I am seeing a scrolling ghost image
of what lloks like a grey pencil drawing of all the edges of my car with
the allow wheels scrolling across of what is the vegetable patch.
So Something from Cam 2 is getting into Cam 8.
I have already tryed unpplugging cam 1 from the DVR and plugging into
another camera input. the problem is still there
I also have tried unplugging cam 8 from the DVR and tried it in another camera input. the problem is still there.
So it does not appear to be video cross talk from within the DVR.
I have a bank of 10 UHF mods, I have already tried turning these off and unplugging the video leads between this UHF bank and the DVR, the problem remains so it is not video crosstalk across the 1o UHF modulators.
I have another theory but would like to open to the floor what the
audience think?
Power supply intermodulation, ro maybe the signal levels in the cables are high enough to cause it no matter what you do, unless they are completely separated?
Brian
On 07/01/2022 09:44, Brian Gaff (Sofa) wrote:
Power supply intermodulation, ro maybe the signal levels in the
cables are
high enough to cause it no matter what you do, unless they are completely
separated?
Brian
If there was PSU intermodulation, would you not expect all 8 cameras to
be affected and how does that allow a ghost image from one camera to get
into another?
I am wondering if a 0v black wire has become disconnected somewhere do
DC ground is now being provided via the co-ax outer screen?
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