COAXIAL CABLE RECOMMENDATIONS
Careful selection of the proper cable is
A
to obtain the bestperformance from this equipment.
Vicon assumes no
when
cables other than those recommended are installed. In all
cases, coaxial cable impedance should be 75 ohms.
Materials
Use only cable with a pure copper center conductor. Do not
use cable with either a copper-plated steel or an aluminum
center conductor because these do not transfer signals effec-
tively in the frequency range used in CCTV networks. A
center conductor with low DC resistance is required for
effective CCTV operation.
Solid-core bare copper conductor is best suited to video
applications, except where flexing occurs. If the coaxial
cable will be subjected to flexing during normal use, select
a cable with a stranded center conductor.
The preferred dielectric material is cellular (foam) polyethyl-
ene. It has better electrical characteristics than solid polyeth-
ylene, but is more vulnerable to moisture. Therefore,
solid polyethylene dielectric cable with a heavy exterior
insulation in applications subject to tnoisture.
The shield must be copper braid providing 95% or better
coverage.
Installation Tips
Do not stretch cable or subject it to sharp bends.
Keep the cable out of contact with hot pipes or any other heat
source. Even
is notenough heattocauseobviousdamage
to the cable, transmission characteristics will be affected.
In locations
cable must be continuously flexed (for
example, with scanners or pan-and-tilt drives), use cable
intended for such movement. This cable will have stranded
wire center conductor.
Use only crimp-type BNC connectors.
Cable Types and Operating Distances
The most commonly used cable types are RG-59/U and
RG-II/U. Each is actually a family of cables with widely
varying electrical characteristics, some of which are not
suitable for CCTV applications.
The maximum camera-to-unit distance for the three most
common cables is listed in Table A. The characteristics of the
cables in this table should be used as a guideline when cables
other then Belden are used. Materials and construction must
follow the guidelines above. Table B gives some equivalent
cable numbers of other manufacturers. Vicon recommends
the following coaxial cable types, unless otherwise specified
elsewhere in this manual.
TABLE A
RECOMMENDED CABLES
‘BC = bare copper,
= tinned copper
TABLE B
DC RESISTANCE (OHMS) PER 1000 FEET OF EQUIVALENT CABLES
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