Choosing coaxial cable and twisted pair for video surveillance

Installation of any video surveillance system, with the exception of wireless, is never complete without a cable. The cable transmits the video signal from the camera to the DVR, provides power, and also connects additional devices, such as a microphone. There are not so many types of video cables today; in this material we will tell you about the most common and widely used ones.

The choice of cable for video surveillance depends on a number of key points. For example, when installing IP video surveillance, a twisted pair wire is usually used, i.e. a regular network LAN, similar to the one with which we connect a computer to the Internet. The cable for IP video surveillance has one interesting feature: using it, you can not only connect the camera to the DVR to transmit a video signal, but also supply power to the camera, and also connect an audio recording device. We'll talk more about twisted pair later. We will also look at the 3 main types of cables used for video surveillance purposes, but first things first.

Technical requirements

1. High-quality material from which the product is made, not underestimated resistance and cross-section. It is important to remember here that a good price does not mean good quality. TU cable is cheaper than GOST , which is due to lower quality.
2. The actual cross-section of a good cable should not deviate from the declared one by more than 10-15 percent.
3. EAC marking , which means that this cable complies with several dozen standards, including all necessary GOSTs.
4. In addition to the label, the corresponding marking should be on the cable itself - factory marking, factory specification marking.

Currently, the requirements are regulated by GOST R 53880-2010 “Coaxial cables for cable television networks.”

How to connect to a digital video recorder?

It is not possible to directly connect an analog camera to a digital video recorder, router or computer network card. The first step is to acquire special transmitters that allow you to convert an analog signal to the TCP/IP protocol. It is with the help of such transmitters that the analog signal will be converted to digital. You will also need a twisted pair cable with a standard connector pinout (the crimping procedure is similar to IP cameras and other devices operating using the same protocol).

The first difficulty may arise when converting an analog signal to a digital one; a regular adapter is clearly not enough. The choice of suitable equipment for signal conversion can also cause difficulties; not all analog-to-digital converters will produce good video quality and stable operation; when using the cheapest devices, the quality of shooting can suffer greatly

The procedure for connecting and configuring devices is as follows:

1. The first step is to install the video camera and connect it to a power source.
2. Connect the camera to the converter (receiver) using a coaxial cable.

3. Connect the transmitter to your computer's network card, recorder or router via a category 5 cable (twisted pair). If the cable is category 5 without connectors, first crimp it according to the appropriate diagram (for connecting to a PC the diagram will be “computer-to-computer”, for connecting to a recorder or router “computer-to-hub”). Although for most modern IP cameras the connection diagram is not critical. When using a router, you may need to open additional ports through the router settings.

4. The device to which the A/D converter is connected will need to be configured. When connecting to a PC or router, you need to open a browser and enter the IP address of the transmitter (indicated in the instructions or on the device body), this is done on the recorder in the appropriate settings. It is strongly recommended to change the standard IP, login and password for security purposes, otherwise the cameras may be hacked by malicious people.
5. The image is displayed and you can start recording. For ease of use of cameras, it is recommended to install specialized software for video surveillance on computers (using a regular browser for such purposes is not recommended).

Coaxial cable for video surveillance

Components of a coaxial cable

The most commonly used cable for connecting analog cameras is a video surveillance coaxial cable, like the one that connects an external antenna to a TV or receiver. This type of cable consists of a copper core encased in a thick layer of foam dielectric, which is covered on the outside with a shielding protective sheath, which provides good protection against interference and possible signal loss. The most commonly used brands for video surveillance are domestic brands RK-75-2-13, RK-75-4-12 (RK - radio frequency cable), or imported analogues - RG-59, RG-6, RG-11.

When choosing a coaxial cable, it is necessary to take into account such important parameters as the length and location of installation (indoors or outdoors), and depending on this, purchase a suitable brand of wire.

If the cameras are significantly removed from the DVR and from each other (the line length is more than 200-300 meters), the transmitted signal can weaken significantly: a simple axiom applies here - the longer and thinner the cable, the greater the signal loss. So when choosing, it is very important to take into account the laying distance, and, based on it, choose the appropriate cable for video surveillance systems.

For example, we lay RK-75-2-13 with a line length not exceeding 100 meters, and for longer distances (from 100 to 300 meters) we use grades RK-75-3-..., for distances over 300 meters we usually use UTP (more on this below).

The RG-6 cable differs from its Russian counterparts RK-75 primarily in that it has a larger diameter of the central conductor and sheath. It is also capable of transmitting a slightly larger range of frequencies than RK-75; for example, HD-SDI cameras refuse to work with RK, and transmit the signal perfectly via RG-6 with a line length of more than 10 m.

For clarity and greater detail, we present a table showing the dependence of wire type on distance.

Cable selection depending on the distance of the recorder to the camera

When choosing a coaxial cable for video surveillance, be sure to make sure that the center conductor is entirely copper, otherwise the signal will be very weak.

Among other things, coaxial cable differs according to other technical criteria, such as:

• Flexibility - in cases where laying a video cable requires bending it in several places, it is necessary to purchase a wire with a multicore central conductor, which will have increased flexibility compared to a monolithic one.
• Characteristic impedance – for video surveillance, cables with a resistance of 75 Ohms are most often used;
• Degree of protection against interference – presence of shielding shells;
• Insulation diameter;
• The degree of signal attenuation;

Pros. The main advantage of this type of cable is its high resistance to interference, affordable price, and ability to transmit both video and audio signals.

Minuses. The disadvantages of coaxial cable include the high cost of connectors, easy damage, and restrictions on laying distance. When using RK brands, there is a need for a separate routing of the power cable, although this point cannot always be considered a disadvantage, since for budget systems, the power supply option via a separate cable will be much cheaper - the savings lie in supplying power to several cameras simultaneously, as well as in the high cost of KVK.

Also, when providing power separately from the main signal transmission cable, it becomes possible to connect cameras to the network away from the DVR, which is almost impossible to do using a combined cable.

Combo cable with power

Combination cable

In cases where the camera is powered and the signal is transmitted from one point, it is most convenient to use a combined cable for video surveillance systems. It is suitable for both analog and digital devices. This is still the same coaxial wire with a resistance of 75 Ohms, but in one bundle with the power wires. Thanks to this interweaving, power to the cameras and signal transmission can be provided without laying additional wires.

Also, in addition to everything, such a cable may contain wires for connecting additional functional elements (for example, a microphone), and for controlling the camera (for example, for controlling the camera's rotating device). An example is the KKSEV cable, which, in addition to the coaxial core, has separate wires for power and audio signals.

A combined high-frequency cable (HFC) with power cores is one of the most expensive. It is used when creating a video surveillance system in which each camera will be connected to the network using a separate power supply, each +12V output of which is equipped with an individual fuse, or with a small number of cameras.

Among the most commonly used combined cables for video surveillance are the following brands: KVK-2P, KVK-V-2.

Features of cables for street video surveillance

Since we've touched on a small portion of what an outdoor cable should look like, we encourage you to continue learning more about the larger facts surrounding this topic.

In order to choose your cable, you need to decide on the place where you are going to install it. The following options are suitable:

1. Laying wires on walls or along their surface. This is the standard installation method.
2. By air on a supporting cable.
3. Underground. Pipes and trenches are perfect.

In addition, do not forget that the cable acts as a power source, which means that it must charge the video cameras in a timely manner. Contact a specialist with outdoor measurements to help you decide on a cable that would be ideal for your area.

Cable length and protection

Each cable has a different length, since the distance from the camera to the personal computer is not always the same. Some wires, such as USB, are as short as possible - 10-40cm, while others are long - up to 3 km. This ambiguous number is explained by the fact that cables are divided into outdoor and indoor.

The protection of the wire lies in the material from which it is made. Most often, this is a dense rubberized base, thanks to which the cable is not subject to rapid wear. Street wires are characterized by the presence of additional processing - shielding. It protects the entire surface of the cable from mechanical damage and climatic conditions.

Climatic performance

To find out in which zone your cable will feel most comfortable, you should learn to read what the manufacturer leaves for us. For example, you know that U1 is work in a temperate climate outdoors. Now we will teach you how to read the climatic design of cables.

Principle of operation and features of operation

Data transmission over certain distances, regardless of the channel used, is subject to various interference. This interference gradually drowns out the useful information signal. When its strength drops to the level of interference, it is almost impossible to distinguish and isolate the necessary data from the general background.

The principle of operation of a twisted pair cable is a symmetrical line. In such connections, when transmitting data, interference is also transmitted symmetrically. And when they converge, their mutual destruction occurs, due to which the main data is easily recognized.

This principle of operation is ensured by the special design of the line, which, in addition to the cable itself, also includes a transmitter-receiver pair. Of this equipment, the transmitter is responsible for receiving and converting the video camera's unbalanced signal into a symmetrical one. Then it is amplified and sent to the receiver. At the receiver, the signal is re-amplified and converted back to single-ended form.

But this scheme also has a couple of nuances. Even this transmission method, although it allows you to neutralize interference, still does not exclude the weakening of the useful video signal. The transmission range in such systems is 50 Hz – 6 MHz. And since the channel capacity is much larger, the signal is supplied unevenly. Moreover, the higher the frequency of the transmitted video signal, the more it weakens. In addition, the degree of attenuation is also directly proportional to the range of the line used.

As a result, we can conclude that this transceiver format, also called passive, is suitable only for small cable infrastructures. Over longer distances, transmission is better achieved by active equipment. Such equipment includes various designs of jumpers or trimming resistors. With their help, two types of signal strength adjustment are carried out:

1. Using a jumper – stepwise adjustment;
2. Due to the resistor, the line is adjusted more smoothly.

The first type of equipment is quite easy to use. After calculating the total length of the line, jumpers are installed on precisely calibrated sections, which amplify the signal. Of course, there is no need to talk about fine tuning here, but for most surveillance systems they are quite sufficient.

A trim resistor can provide finer tuning. But this is only possible if additional equipment is used. However, not every master can adjust such a scheme.

By implementing the above measures and properly configuring the system, the signal transmission range over twisted pair cable can be increased from the standard 2 km to 3-4 km.

Cable variety. Why is the right choice so important?

The technology used to transmit video signals from one location to another is one of the most important components of a CCTV system. The market offers many solutions for connecting components into a single whole. Here are some popular options:

• twisted pair network cable;
• coaxial cable and its varieties;
• high-tech fiber optic cables;
• wireless video transmitters and receivers.

A faulty camera can be replaced under warranty. Freezing DVR - reconfigure. Network connections are easy to reconfigure. But if, after installation, an inexpensive and seemingly simple cable refuses to work, then you will have to first find the problem and then start all over again.

The article will tell you how to choose such a cable, the intricacies of installation, connections and permissible distances. The “picture” will definitely appear on the screen even from a camera several hundred meters away, if you study the tips given. An additional bonus is recommendations for connecting a TV, monitor and other popular devices to video surveillance. Although the article is intended for a non-specialist user, we will be glad if an experienced professional learns something new for himself.

twisted pair

The use of twisted pair cables became widespread with the advent of computers. This type of cable is used when connecting a PC to the Network, installing digital surveillance cameras, various electronic devices and when creating computer networks. Structurally, a twisted pair consists of eight thin wires, which are combined in pairs and covered with a common sheath on top.

UTP FTP STP

Depending on the design, the following types of such cables are distinguished:

• UTP is the simplest type of product that does not have a protective screen. This cable has a low price, but it is not resistant to interference, so when laying in close proximity to electrical wiring, it is recommended to use other types (with high noise immunity).
• FTP is a cable with a common protective sheath of foil. The presence of a screen allows installation in close proximity to the wiring without worrying about interference. During installation and operation, it is important to monitor the integrity of the foil, avoiding excessive bending. External cable protection is provided using solid polyethylene or PVC.
• STP. A feature of products of this type is the presence of a more powerful screen (copper braid is used). In addition, the conductors in the cable are also made of solid copper, insulated with polyolefin and have a personal foil shield. Fire-resistant polyvinyl chloride is used as external insulation. An STP cable is the best option when the video camera is connected at a distance of more than 90 m from the recorder and in the presence of a lot of interference.

When choosing, pay attention to a number of characteristics - the diameter of each conductor, the speed of information transfer, the type of outer sheath, as well as the number of cores (single- or multi-core).

The advantages of the cable are ease of installation, low cost (when compared with a coaxial product), the ability to transmit a “picture” over a distance of up to 3000 m, as well as wide functionality. The disadvantages are the low level of protection against interference (for some types), as well as the need to install amplifiers when installing video surveillance over long distances.

Coaxial cable installation guidelines

In order to protect yourself from most problems when laying this type of cable, you must adhere to the following rules:

1. Avoid laying wires parallel to the power ones and do not place them closer than 30 cm to each other. Noise from the electrical network may take the form of several horizontal stripes on the monitor screen that slowly move down (or rise up);
2. Avoid loops and bends in the cable during installation, as they disrupt its uniformity, which can lead to the loss of small parts of the picture or doubling of the image. The image quality will be better if the loop bend is at least 5 times the diameter of the coaxial cable. During operation, the central wire may break off at a bend, which will lead to a complete loss of the video signal;
3. Use only a single piece of cable and under no circumstances use so-called “twists”;
4. To reliably connect video system components, it is recommended to use special BNC connectors, and leave a sufficient supply of cable in places of future connections.

BNC connectors

In video surveillance, special connectors are widely used to connect coaxial cable to cameras, DVRs, or connect two cables to each other. The most common are BNC connectors. They come in three types - crimped, soldered and threaded.

The experience of many installers has shown that crimp connectors are the most reliable. Their connection order is as follows:

1. Carefully cut the outer layer of cable insulation with a sharp knife - about 20-30 mm from the end;
2. Place the metal sleeve over the insulation;
3. Bend the braid (screen) back towards the insulation;
4. Cut off the translucent plastic of the dielectric, in the center of which the signal core is located;
5. Place a BNC connector onto the copper core. The “screen” braid is evenly applied over the connector;
6. We move the metal sleeve to the end of the wire so that the braid is underneath it. The coupling is fixed to the connector using a special tool (it is not recommended to use pliers for this). The BNC connector is ready to be connected to the recorder.

We will tell you more about this type of connector in the next article.

Cable for analogue systems

Let's first consider what cable is needed for analog systems and AHD.

In order to receive a picture from any video camera and transfer it to a video recorder or monitor, you must at least fulfill two conditions:

• supply power to the camera

• take a video signal from it

The most convenient way to do this is with a cable that already combines these functions. That is, there is a coaxial cable for transmitting a video signal and there are also 2 power wires - plus and minus from the 12 volt unit.

Assembling these wires separately today is extremely irrational and unreliable.

Not so long ago, the most common options for this were:

• ShGES cable

• ShVEV and ShVEP cable

If you are making a video surveillance system, as they say, “for yourself,” then these brands are not recommended.

ShGES are two or more wires that are covered in copper braiding. One of the conductors supplies power, the other a video signal.

Due to the very low cost, many analog video systems were built with these wires. True, the distance from the power supply to cameras based on such a cable should not exceed 15-20 meters.

The SHVEV cable consists primarily of 3.4 copper or copper-clad flexible conductors. One of the cores is braided.

When using this cable, simply forget about such parameters as a characteristic impedance of 75 Ohms. However, the signal can still be transmitted over short distances.

The popularity of this cable is also explained by the fact that with 4 cores, sound can be transmitted through an unused core.

Useful tips for choosing

In conclusion, we highlight the main recommendations that will help with the correct choice of cable for video surveillance:

• When installing IP cameras, the best solution is to use a UTP cable with an RJ-45 connector.
• For analogue video surveillance, the classic “coaxial” is suitable if the distance between the camera and the recorder is no more than 100-300m.
• In a situation where signal transmission and power supply are carried out via one cable, it is better to use a combined option.
• If you use a large number of cameras, you should use STP, FTP or UTP cables. Here, focus on distance and the need for protection from interference.
• For outdoor cameras, use products with a protective shell made of rigid polyethylene. When installing a video surveillance system inside various structures, a cable with a PVC sheath is suitable. If you need to mount an external system, it is desirable that the cable structure has a steel cable, which provides greater strength to the product (relevant if there is an air laying).

Sources

• https://svs.guru/videonablyudenie/komponenty/kabel.html
• https://nabludaykin.ru/kakoj-kabel-vybrat-dlya-videonablyudeniya/
• https://vektor-video.ru/kabel
• https://vsesecurity.ru/videonabludenie/kakoj_kabel_dlya_videonablyudeniya
• https://bezopasnostin.ru/videonablyudenie/videonablyudenie-po-vitoj-pare.html
• https://videostoraj.ru/videonablyudenie/kakie-byvayut-vidy-kabelej-dlya-videonablyudeniya
• https://azbsec.ru/articles/videonablyudenie/vybiraem-kabel-dlya-videonablyudeniya.html

Which one is better to choose?

Which cable to choose for a video surveillance system?

Typically, choosing the right type of CCTV cable depends on your specific situation, your desires and the cameras you choose. In the case of IP cameras, this is almost always the unambiguous use of a UTP cable with RJ-45 connectors; analogue video surveillance with a small number of cameras can get by with a regular coaxial cable at distances not exceeding 100-300 meters, and to be able to supply power and transmit signals over one cable it is necessary use either a combined video surveillance cable with power or twisted pair cable. If you have a large number of cameras and longer distances, we would recommend using a twisted pair cable - UTP, FTP or STP cable - depending on the distances, location of use (outdoors, indoors) and sources of interference.

The differences in the location of communications will be that for external cameras it is necessary to use a cable with protective external insulation made of solid polyethylene, and for internal video surveillance systems it can be taken from ordinary PVC. Also, a cable for outdoor installation may have a steel support cable in its design, which is necessary to enhance the strength of the cable when laying the cable through the air (KVK-Pt).

In this article, we tried to analyze as much as possible the question of how to choose the right cable for video surveillance, talked about the main types and their characteristics, tried to highlight in as much detail as possible those design differences that play a major role in choosing the most suitable cable depending on a particular CCTV systems and your preferences. We wish you good luck and hope that this material remains useful to you!

With this they read:

Analogue CCTV cameras vs IP: what to choose?

DVRs "Line": great opportunities at a competitive price

Choosing a hard drive for video surveillance

Differences and criteria for choosing street CCTV cameras
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1. Ilya
   04/14/2017 at 12:09

   good afternoon!!! The distance to the cameras is 160 meters!!! what cable should I use? did you want a regular home twisted pair cable or is it too far?

   Reply ↓

   Alexander Starchenko

   (Post author)04/18/2018 at 05:25

   Hello, Ilya. You can use a repeater every 80 meters, but AHD and TVI digital cameras would be better. They now have a resolution of up to 5 megapixels, a range of up to 500 meters.

2. Anonymous

   03/24/2019 at 03:25

   there are laser cameras up to several kilometers

Fiber optic cables: the choice for serious projects

Both analogue and digital cameras use the legendary but increasingly affordable fiber optic. Cables of this type are absolutely not subject to electromagnetic interference; the distance to the source can be measured in tens of kilometers; signal attenuation is barely present in them compared to traditional wires.

But until now, the use of fiber optic cables in the “office” and “home” video surveillance segments has more disadvantages than advantages:

• installation requires professional skills and specific tools. A non-specialist cannot do without significant costs, both in time and money;
• additional costs for fiber video receivers and transmitters in addition to the high cost of the cable itself (about 60 - 300 rubles per meter);
• poor flexibility compared to coaxial and twisted pair: light “wires” are susceptible to bending, stretching and physical impact.

Optical cable for video surveillance is successfully used in larger facilities than a house, cottage or small office. In this area, optical fiber has serious advantages. As a rule, optical fiber is used as a “means” for transmitting information, because In any case, you will need to use some signal converters (transmitters and media convectors) to connect the video camera via fiber optic.

The end section of a video surveillance system: computer network

This section probably doesn’t really relate to wiring. But it is the segment of the video surveillance platform “from the recorder to the computer (router)” that raises more questions for beginners. Paradoxically, this is also the simplest part of the system. And power supply is not required here, although it is also possible via a LAN cable - PoE technology is increasingly supported by “civilian” devices.

The video signal received from the cameras is processed by the DVR, simultaneously recorded on the hard drive inside the DVR, and, if desired by the owner, broadcast to the screen of a TV, computer monitor, smartphone or tablet. Even to the other side of the planet, if the system is connected to the Internet.

The method of connecting the DVR with surrounding computing devices (PCs, laptops, mobile gadgets) is a classic computer network. Usually - the Internet connected to the router, which is distributed to devices via Wi-Fi. At the same time, Wi-Fi connects different devices with each other. The DVR should become one of the gadgets connected to the network: from the point of view of the router, it is no different from a laptop or smartphone.

To transmit a video signal in the segment between the DVR and the router, it is enough to use a classic network cable (twisted pair) and stretch it from the DVR to the router.

And the existing Wi-Fi network can handle the broadcast of the video signal from the router to end devices (computers and mobile devices). Communication delays in this segment are minimal; stringing wires from the access point is a thankless task.

Video signal over twisted pair for IP cameras

Coaxial cable is a good solution for common video surveillance systems - analog and intermediate solutions (the fashionable analog-based high-definition standard - AHD). An alternative option is a platform without a “think tank”, i.e. without DVR. These are IP cameras that transmit a signal directly to a computer or local network. This solution is beneficial when there are a small number of surveillance sources (1-3), or it is justified when broadcasting a signal over the Internet to remote users, bypassing local surveillance.

The cable for IP cameras is a twisted pair cable (other names are LAN, “network”, UTP).

Types of twisted pair:

• UTP - unshielded twisted pair without a protective shield;
• F/UTP - twisted pair is shielded by a common external foil shield;
• F/FTP - twisted pair is shielded by a common external foil shield, in addition, each pair is separately shielded;
• SF/UTP - twisted pair is shielded by a double common external shield made of copper and foil;
• S/FTP - twisted pair is shielded by a common external copper shield, with an additional foil shield on each individual pair.

Associated with twisted pair cable, the abbreviation PoE (Power over Ethernet) is a technology that provides power. Modern devices that do not require current power (cameras are among them) are able to receive electricity through the same wire from which the digital signal comes. A power source is connected to the POE adapter; the output is a twisted pair cable with a signal and electricity. Safe and convenient solution.