Reference
Coaxial cables used to route video signals to and from the unit must meet the video recommendations in this section.
Caution: Careful selection of the proper cable is essential to obtain the best performance from this equipment. Vicon assumes no responsibility for poor performance 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 effectively 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) polyethylene. It has better electrical characteristics than solid polyethylene, but is more vulnerable to moisture. Therefore, use only solid polyethylene dielectric cable with a heavy exterior insulation in applications subject to moisture. The shield must be copper braid providing 95% or better coverage.
Cable Types
The most commonly used cable types are RG-59/U and RG-11/U. Each is actually a family of cables with widely varying electrical characteristics, some of which are not suitable for CCTV applications. Choose a cable type by referring to the characteristics and maximum distances listed below. The maximum distance for best picture refers to the distance between the camera and the unit The characteristics of the cables in this table should be used as a guideline when cables other than Belden are used. Materials and construction must follow the guidelines above. Note that “BC” refers to bare copper and “TC” refers to tinned copper.
Recommended Coaxial Cable Types
| Cable | Belden | Alpha | West Penn | | Type | | | | | DC |
| Center | | Type Shield and | | Resistance |
| Type | Type No. | Type No. | Type No. | Conductor | | % Coverage | | ohms per |
| | | | | | | | | | | | 1000 feet |
| | | | | | | | | | | | (km) |
RG-11/U | 8213 | 9847 | 811,4811 | | 14 Solid BC | BC braid (95%) | | 2.6 (8.5) | |
RG-6/U | 9248 | 9804C | 806,4806 | | 18 Solid BC | Foil + 61% TC | | 7.5 (24.6) | |
| | | | | | | | braid (100%) | | | |
RG-59/U | 8281 | 9803 | 815 | | 20 Solid BC | 2 TC braids (96%) | | 9.9 (32.5) | |
RG-59/U | 9259 | ---- | 816 | | 22 | Stranded | BC braid (95%) | | 15.0 (49) | |
| | | | | | BC | | | | | | | |
RG-59/U | 9659 | ---- | ---- | | 22 | Stranded | BC braid (95%) | | 15.0 (49) | |
| | | | | | BC | | | | | | | |
| | | Picture Quality vs Cable Length | | | |
| | | | | | | | | Maximum | | | |
| | Picture Quality | | | | | | Cable Run* | | | |
| | | | | | | | | ft (m) | | | |
| | | | | | RG-59/U | | RG-6/U | | | RG-11/U | |
| Usable picture | | | | 1100 (350) | | 1500 (450) | | 2400 (750) | |
| Clean picture | | | | 820 (250) | | 1000 (300) | | 1600 (500) | |
| Best picture | | | | 400 (120) | | 530 (160) | | 820 (250) | |
For longer cable runs, refer to the Product Specifications for Video Amplifiers.
1.5-inch Pipe Designation
The standard “1.5-inch pipe” referred to in this manual has actual dimensions of: Outside diameter: 1.9 inches (48.3 mm).
Inside diameter: 1.61 inches (40.9 mm).
Wall thickness: 0.145 inches (3.37 mm) minimum (ANSI “standard” grade thickness).
XX152-02-00 Rev 1004 SurveyorVFT Fixed Camera Dome | Reference • 19 |