Re: Is this how CCTV caneras die?

[Richard Malcolm-Smith <rich@xxxxxxxxxx>]

rb_ziggy wrote:

> Having finally got my front door CCTV working how I want it (the
> motion detection, email of picture and web streaming active only when
> the alarm is set), I'm now wondering if the camera is now on its last
> legs.
>
> I've had the camera for 2-3 years.  What I'm seeing is a horizontal
> pale band (sometimes 2)slowly scrolling down the picture and then
> starting from the top again.  The output from the camera is passed
> through a modulator and then distributed via a Loftbox on coax.



> I don't think I've done anything recently that would cause
> interference on this camera channel so I'm wondering if it is the
> camera or modulator.  Difficult to tell as I have no spares to swap
> out and test.
>
> I'd probably live with it until whichever component totally dies but
> the scanning line is giving false triggers to the motion detection so
> the resulting emails get fired off and pile up a bit.

The line is 50Hz being superimposed on the video signal.

It may come from either a shot powersupply for the RF amp, or the camera,
or
more likly a ground loop you have made between the PC and a TV/DVD/Sky box
which
is now grounded via the coax to the PC.

unplug the mains plug to any and all interconnected gear, and see if the
line
goes, if it does, put a braid breaker on the line to the PC - you can make
your
own with 2 baluns hooked back to back generally, but check them for any
electrial connection between the coax and the 300 ohm terminals.

If you dont get it clear up with the other stuff powered down, then go any
buy
new AC adaptors for the camera and the RF amp if they are seperate. Not
uncommon
for the electorlytic caps in the older transformer based ones to die from
the
contant warmth and the cheapness of them.


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