the effect of coaxial cable and cat-5 cable loss

the effect of coaxial cable and cat-5 cable loss
Why your CCTV images are not as sharp as they should be.
This graph illustrates the picture quality obtained when transmitting a CCTV picture through
various lengths of RG59/U cable, and the restoration of picture quality obtained by using the ACE472
at the monitor end of the system. Note that only 80% of the picture quality remains after going through
350 feet of coaxial cable, and 50% is missing after only 1100 feet of cable. By 2000 feet, 75% of the
original picture detail is gone. This picture detail can be recovered!
When the “Cable Ace” ACE472 is connected at the monitor end of the cable, 100% of the
original picture detail will be delivered by coax or twisted pair wire up to 3000 feet long. Even after a
5000 foot run the picture quality is still as clear as a 600 foot run of RG59/U.
All cables introduce some loss of picture brightness and clarity. The longer the cable run the
greater the loss. The loss of picture clarity is usually more noticeable than the loss of brightness as the
cable length between the camera and the monitor becomes greater. Picture quality is often measured in
terms of “Lines of Definition” on camera and monitor specification sheets, but coaxial cable and CAT5 twisted pair wire are not rated in this way because the “Lines of Definition” rating of the cable varies
with the length of the cables. The overall picture quality delivered to the monitor requires that the
camera, monitor, and cable all be capable of handling the picture quality desired. Once the camera,
recorder, and monitor have been selected to produce the desired system quality, then overall system
quality will depend entirely on the loss produced by the cable or twisted pair wire connecting the
camera to the monitor.
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One frequently used measure of the degree of quality loss in pictures transmitted over cables is
when ½ of the energy required to produce those “Lines of Definition” is lost in transmission over the
cable. Note that “Lines of Definition” does not refer to the number of picture lines being transmitted.
In fact the number of picture lines in an NTSC CCTV picture is always 525 lines, regardless of the
number of “Lines of Definition” being transmitted. The term “Lines of Definition” refers to the
number of vertical lines that could be resolved in a picture. That is why a “Lines of Definition” test
pattern contains progressively finer and thinner vertical lines to denote higher definition. The following
table shows the maximum length of Coaxial Cable and CAT-5 pairs that may be used to deliver
standard “Lines of Definition”:
LINES
330
400
470
570
700
RG59/U
686 Feet
615 Feet
585 Feet
521 Feet
470 Feet
CAT-5
289 Feet
259 Feet
246 Feet
219 Feet
198 Feet
RG59/U plus ACE472
5300 Feet
5200 Feet
5100 Feet
4900 Feet
4700 Feet
The table shows the maximum distance in feet that can be used and still obtain the desired
number of “Lines of Definition” for RG59/U coaxial cable and twisted pair wire “CAT-5” cable pairs.
Much greater lengths of cable can be used when an ACE472 Cable Ace is connected at the monitor
site. The ACE472 can be ordered for coaxial cable or twisted pair wire input.
Note that the CAT-5 (twisted pair) type of transmission typically transmits about ½ the distance
as coaxial cable at the same quality level when transmitted over non equalized cables, however, the
quality of the pictures on both coaxial cable and CAT-5 facilities will be full quality when the ACE472
is connected at the receiving end of the system.
The coaxial version of the ACE472 Automatic Cable Equalizer will enable your picture to be
transmitted for any distance up to one mile, precisely compensating the cable automatically for its
exact length. If switched to another, different length of cable, the ACE472 will automatically re-adjust
to correctly compensate for the new length of cable. The ACE472 will correctly compensate for any
number of “Lines of Definition” and any distance up to one mile on any coaxial cable type.
The twisted pair wire input version ACE472-UTP will compensate the twisted pair wire run for
up to 3000 feet automatically.
The picture brightness and frequency response correction provided by the ACE472 is totally
automatic and does not require any routine adjustments. That means that all cameras and cables
connected to the “Cable Ace” will always have the same peak brightness and the best possible picture
clarity. The length of the cable is no longer a factor in CCTV picture quality when the ACE472 is
employed. The ACE472 will correctly compensate High Definition cameras as well as Standard
Definition cameras, all automatically to provide the highest definition possible for the cameras and
monitors connected into the system. This means that a system can be upgraded with the ACE472 alone
and then further upgraded by replacing the standard definition equipment with high definition
equipment.
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