| Coax
Characteristics |
| |
Pure copper center conductor
- Not copper covered steel as used in CATV or
MATV systems. Copper braid with at least 95%
coverage. - Not foil shield.
DC resistance total system 20 ohms or less.
(Measured center conductor to shield with one
end shorted.)
Stranded for excessive cable movement
RG59U - Do not exceed 800 feet
RG6U - Do not exceed 1300 feet
RG11U - Do not exceed 2000 feet
Proper coax will provide good signals to the
monitor location.
|
| Video
Signal Termination |
| |
Always terminate the video
signal ONLY at one place and ONLY at the end.
Some equipment will "Auto-terminate".
Look for a switch or jumper. If present, set
correctly.
|
| Ground
Loops.How to Detect/Correct |
| |
One lead of
meter is on the coax shield, the other is on the
monitor case. Any AC reading indicates a ground
loop. The severity of the ground loop usually
determines the effect of the video signal. A 100mv
ground loop can cause a problem. A ground loop
usually appears as a thick black band scrolling
upward on a monitor. |
| |
Actual Ground
Loops |
| |
|
Difference in AC ground
from camera to monitor locations.
Install a V235GLTA
in the coax line (close to the monitor location).
|
| |
"Induced"
Ground Loops |
| |
|
In master transformer applications,
differences in AC power to individual cameras
can cause AC to loop through coax. This occurs
mostly when a camera does not have a built-in
isolation transformer. |
| Lens
Adjustments |
| |
ALC: |
| |
|
Selects the type of lighting
condition to which the lens LEVEL adjusts |
| |
PK (Peak)
setting: |
| |
|
Adjusts the lens on any
bright peak light in the scene. This could cause
the remaining picture to appear dark. |
| |
AVG (Average)
setting: |
| |
|
Adjusts the lens on an
average of the bright and dark light. |
| Level |
| |
Controls how
much light comes into the imager. "L"-Low, "H"-High
Works in conjunction with the ALC setting With
camera/lens viewing the bright area, adjust the
LEVEL pot (clockwise) to point where the picture
begins to bloom, then turn back to remove bloom.
This will provide the best overall setting for
both low and bright conditions. |
| Back
Focusing |
| |
Fixed -
Auto-Iris |
| |
1) |
Hold dark filter in front
of lens. This filter should be dark enough to
open the iris, yet allow camera operation. |
| |
2) |
Adjust the lens focus ring
to mid-range position. |
| |
3) |
View distant object within
desired field-of-view. |
| |
4) |
Adjust camera's focus position
to obtain sharp focus. |
| |
5) |
Tighten focus adjustment
screw Remove filter. |
| |
6) |
Camera should remain in
focus during day and night viewing. |
| |
Zoom - Auto-Iris |
| |
1) |
Hold dark filter in front
of lens. This filter should be dark enough to
open the iris, yet allow camera opera- tion. |
| |
2) |
Viewing distant object
(approx.75ft), adjust lens' zoom to widest angle. |
| |
3) |
Adjust cameras mechanical
focus position to obtain a sharp focus. |
| |
4) |
Adjust lens' zoom to telephoto
angle, viewing distant object. |
| |
5) |
Adjust the lens' motorized
focus to obtain a sharp focus. |
| |
6) |
Remove filter. Camera should
remain in focus through entire zoom range. |
| VCR
Maintenance |
| |
If there are
excessive dropouts (noise specks across picture)
and TRACKING control does not clear, head clean
ing is recommended. |
| |
Video Head
Cleaning Procedure: |
| |
Tools
required for cleaning: Head cleaning kit, chamois
swab, cleaning fluid. |
| |
1) |
Coat the chamois swab with
the cleaning solution. |
| |
2) |
Touch the swab to the video
head, and gently turn the upper cylinder to the
right until the video head is clean. |
| |
3) |
Do not move the swab up
and down. |
| |
4) |
Make sure that only the
swab comes in contact with the head. |
| |
5) |
Thoroughly dry the head
prior to running a tape. |
| |
Set up a regular routine maintenance of VCR
head cleaning at 3500 hours.
Always replace any tape after it has had over
50 passes recorded on it.
Most VCRs will require a major service including
head replacement, capstan, clutch, idler and
roller replacement at approximately 10,000 hours.
|
| CCTV
Installation Rules |
| |
AC & Coax |
| |
|
Maintain an "Open Air"
separation for every 100volts of AC. Avoid running
high voltage with coax. |
| |
Coax Type |
| |
|
For optimum coax operation,
ALWAYS use a coax with a pure copper center conductor
with at least 95% copper shield. |
| |
Coax Loop
Resistance |
| |
|
For optimum operation,
maintain a less than 20ohm coax loop resistance.
Terminate into 75ohm Load. |
| |
Camera Positioning |
| |
|
To reduce reflections,
always position the camera/lens as forward as
possible inside a housing. |
| |
Proper Focusing |
| |
|
Always focus with the iris
fully open and use a dark filter to maintain an
in focus image during all conditions. |
| |
Line-Lock
and Phase |
| |
|
Always use phase adjustable
line locked cameras in multi-camera systems. When
connecting the video to a switcher, the phase
adjustment feature will help to provide roll-free
switching. - Note: 12vdc cameras do not provide
a Line locked phase adjustment feature. |
