Why is the security monitoring video cable 75 ohms?

April 14, 2023

In order to reduce mutual crosstalk and external interference between loops, the cable is shielded. The shielding requirements of cables are based on different occasions. They are: twisted-pair shielding, total twisted-pair cable shielding, twisted-pair shielding and total shielding and other methods.

Shielding materials are round copper wire, copper tape, aluminum tape/plastic composite tape. The shielding pair and the shielding pair have better insulation performance. If the potential difference between the shielding and the shielding pair occurs during use of the cable, the signal transmission quality will not be affected.

This product is applicable to electronic computers [1] and automatic connection cables whose rated voltage is 500V and below. Cable ground core insulation uses K type B low density polyethylene with antioxidant properties. Polyethylene's high insulation resistance, good withstand voltage, low dielectric constant, and low dielectric loss temperature and variable frequency, not only meet the transmission performance requirements, but also to ensure the service life of the cable.

Technical Parameters:

Product rated voltage (U0/U): 300/500V

Long-term working temperature is 70°C

The ambient temperature during laying is not lower than: fixed laying -40°C, non-fixed laying -15°C

Minimum bending radius: no armored layer should be less than 6 times of the cable diameter, cable with armored layer should not be less than 12 times of the cable's external diameter. When 20 °C, the insulation resistance should be not less than 1m after stable charging with 500V DC test. 2500MΩ·Km

Between each pair of twisted shields and between the twisted pair shield and the total shield shall be subjected to 50HZ between the core and the core of the cable, and between the shield and the shield. The voltage shall not exceed 5000HZ for 5min.

1. AC rated voltage: U0/U300/500KV

2. Maximum working temperature: polyethylene insulation not exceeding 70°C, cross-linked polyethylene insulation 90°C, low-smoke halogen-free flame-retardant polyolefin 70°C, low-smoke halogen-free flame-retardant cross-linked polyolefin 90°C and 125°C , Polyfluoroethylene (F46) insulation does not exceed 200 °C, imported soluble polytetrafluoroethylene (PFA) does not exceed 260 °C

3. Minimum ambient temperature: PVC sheath: fixed laying -40 °C, non-fixed laying -15 °C, fluorine plastic and silicone rubber sheath: fixed laying -60 °C, non-fixed laying -25 °C.

4. Cable installation temperature should not be lower than 0 °C (high temperature type is not lower than -25 °C).

5. Allowable bending radius of cables: The minimum length of non-armored cable is 6 times of the outer diameter of the cable, and the minimum of copper tape shielding or steel armored cable is 12 times of the outer diameter of the cable.
Product Usage:

This product has low capacitance, low inductance, excellent shielding performance and anti-jamming performance. The special high-temperature computer cable adopts imported fluorine plastic and fluorine rubber and other materials, and can be used in the environment of -40-260°C for a long time. The product has non-flammable , acid and alkali resistant oil and water and other superior features, cable structure designed for the safety explosion-proof circuit, not only for the laying of the bridge, but also for the laying of cable trenches and buried laying, special high temperature intrinsically safe computer cable in 2000 won the national patent certificate. Suitable for transmission lines with anti-explosion protection requirements and other harsh environments under the collection and distribution systems, automated detection systems, explosion-proof safety performance is significantly higher than the general DCS cable and computer control cable.

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Author:

Ms. Amy

Электронная почта:

amy@ucoax.com

Phone/WhatsApp:

+8613913156783