Internet Security Systems: Security Alarm Products - Offers commercial & residential wireless security, CCTV, access control, wander prevention, sound, home theater, intercoms and phone systems. Also provides HVAC, structured wiring and cabling, home automation, locks, burglary, and fire equipment needs. .
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CCTV Video Solutions to the Most
Frequently Asked Questions
(What’s wrong with this picture?
/ CCTV FAQ)
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Bright spot smears on monitor
Cameras are designed to view light
reflected from the scene being viewed. When you have a bright light source
in the picture, it may produce a bright white spot on the monitor and a
vertical white line through it. This is a problem especially at night.
Solution:
Reposition camera to avoid bright light
sources in the scene.
Bright background, dark foreground
A bright area in the picture causes the
iris to close or the imager to reduce gain. This causes the unlit area to
appear darker.
Solution: Use a
camera with backlight compensation or reposition camera to avoid bright
background and/or illuminate foreground to even lighting of scene.
Picture rolls when switcher changes
Line locked cameras get synchronization
from the AC power supply they use. If camera power supplies are out of phase
during switching, you will notice a rolling between frames from one camera
to another. This can be confusing to the person monitoring the system. It
can also create problems for your time lapse recorders.
Solution:
Power cameras from the same phase on
your electrical panel or use cameras that have a phase adjustment control.
Picture is snowy or snowy bars roll on screen
The coax cable is picking up
electrical, magnetic, or radio interference. This problem is very prevalent
when using inexpensive cable.
Solution:
Re-route cables away from problem area
and use only good quality cable.
Picture tears horizontally or snowy bars roll
The system is suffering from a
ground loop(s). A ground loop is caused when camera and monitor are powered
from sources using different grounds with different ground potentials. If a
path for current flow (other than the coax) exists, ground loops are
possible. A difference of a few millivolts can cause a ground loop. Ground
loops are not predictable and may appear or disappear after the system is
installed.
Solution:
Install a ground loop corrector or power
all camera from the same source as the monitor.
No picture at the monitor
An open or short in the cable is the
most common cause. Breaks in the center conductors are caused by excessive
pulling or bending, shorts are usually caused by improper connector
installation.
Solution:
Disconnect the cable at both ends and
check with a meter.
1.) From center pin to outer connector should read open. If it reads
shorted, reinstall the connector.
If it still reads shorted, read cable directly. If this fails and cable
still reads shorted, replace cable.
2.) Short one end (pin to outer), meter from other end, it should read
shorted. If it reads open, check the cable directly. If the cable reads
open, replace the cable.
Monitor has “ghosts”
When a video signal is not properly terminated it reflects
back on itself, resulting in secondary images called “ghosts.” Unless you
pass the signal onto another video product, the signal needs to be
terminated.
Solution:
Make sure “Hi-Z/75 ohm” switch is in “75
ohm” position unless looping the video signal on to another device.
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