CCTV basics (for beginners) introduction

This lesson is about the basics of CCTV and is intended for beginners who have no experience in the field if that is your case keep reading.

In this lesson, I will explain in detail the basic concepts of analog CCTV, and how a small recording system with 4 cameras and a digital recorder works.

What is an analog camera?

At first, a CCTV camera has characteristics similar to any traditional camera you know (like the camera on your cell phone) because it has a lens that directs light to an internal image sensor, but the similarities end there because in an analog camera there is no internal SD card for recording.

An analog camera captures images using a lens, image sensor and the internal circuitry system generates the analog electrical signals that are sent through coaxial cables to an external recorder (known as DVR) that converts analog signals to digital format for local recording and remote access.

What is an analog CCTV system?

It's a system with analog security cameras that send the signals to a DVR (Digital Video Recorder) usually located in a rack or a surveillance room.

This type of system is not purely analog because there is a conversion of analog signals to digital, it is, in fact, a hybrid system, but it is very common to hear technicians referring to this type of system as analog.

 

Connecting Multiple Cameras to a DVR

It is possible to connect several analog cameras to a digital recorder (DVR), just get the equipment with an adequate number of channels.

The following image shows 4 analog cameras connected to a DVR that in turn is connected to an analog monitor that displays the images. The system uses coaxial cables designed for CCTV.

Take a look at the diagram, the first block shows the analog cameras that are responsible for generating the video, the second block has the DVR that converts the signals from analog to digital to record and send the video stream to be displayed in the third block where the analog monitor is located.

Note that the analog cameras have different physical formats, in this example, there is a box camera, a dome camera, a PTZ, and a bullet camera successively.

Here is an image that shows a 4-channel DVR and 4 analog cameras.

One of the cameras has the coaxial cable connected to the DVR so that it can send the electric signals to the DVR for digitization and recording.

The purpose of this image is only to illustrate the simplicity of the concept of connecting analog cameras to a digital recorder, it is also necessary to power all devices with a power supply.

The next image shows the back of a DVR, note that there are 4 inputs for the cameras and that the connection of the coaxial cable to the DVR is made by a BNC connector.

There are different types of coaxial cables on the market, in the picture above it is possible to notice that the black cable is thicker than the white one, but the last one has a parallel cable to carry the power to the camera (this type of cable is known as siamese cable).

Cables and connectors for CCTV cameras

Note in the following image that a siamese cable has a BNC connector at both ends and a pair of wires that to power the camera, at one end there's a power connector (also known as P4 connector in some countries) and on the other side the red and black wires are connected to a power source.

If a cable without parallel power cord is used (such as the black cable shown in the picture), it will be necessary to use a separate power cable, which may make the project a bit more expensive, but in some cases this solution is more professional, especially when the cameras are installed far from the DVR and the parallel cable is not good enough to carry the power.

Professional Analog Cameras connectors

This type of separate power connection is quite typical of professional cameras, especially box models that are usually used in special projects.

Note in the image below, this professional camera can be powered with either 24-volt AC (Alternate current) or 12-volt DC (Direct Current) power.

In day-to-day situations for small projects, it is rare to find professional analog cameras of this type due to cost-effectiveness, especially when it is better to use modern IP cameras rather than expensive professional analog cameras.

If the design is small and your concern is cost, it is currently more common to use traditional analog cameras with siamese cables and power connectors.

CCTV camera resolution

There are different analog camera technologies on the market and therefore different types of resolutions, let's discuss this topic.

Analog resolution

The resolution of an old traditional analog camera (CVBS) is measured in TV lines, which is nothing more than the  number of vertical lines that appears on a monitor. The higher the number of lines, the higher the resolution.

Note in the picture below that there are lines on the monitor screen that make up the image, depending on the number of lines the camera can generate it is considered a higher resolution camera, although it is an old technology, we still find cameras with resolutions of 480, 540, 600 and 1000 TV lines, however I do not recommend the use of such cameras.

Digital resolution

As you saw before, after going through a DVR the image is converted to the digital format.

When converted to this format another measurement unit is used  to refer to the resolution of the camera. The term TV lines is not used for digital resolution because the number of pixels that is available in the image is used.

Nomes such as CIF, 2CIF, 4CIF, VGA, SVGA, XVGA, HD, Full HD, Mega Pixel and 4K are used to refer to CCTV digital resolution.

See in the picture below that there are several dots that form an image, they are the pixels and the higher the number of pixels, the higher the digital resolution.

It is possible to have thousands of pixels in an image, in this example, we could have cameras that generate 0.3 to 8 million pixels, that's the reason the resolution is referred in Mega Pixels (MP).

DVR network output

As you saw earlier, a DVR converts the analog camera signals into a digital format so it can be recorded on an internal hard drive, but not only that, the DVR also has a digital output that allows sending the camera images over a computer network and the Internet.

See the following image that illustrates the concept.

Note in this picture that the analog cameras are connected to the DVR that receives the signals in traditional analog format with 600 TV lines (TVL) that are converted to the digital format 4CIF that represents 704 x 480 pixels horizontally and vertically respectively.

This video in digital format is displayed on a computer screen with specific software, note in the diagram that there is a blue cable (network cable) connecting the digital output of the DVR to a computer.

It is also possible to connect a coaxial cable from the DVR to an analog monitor and also obtain a traditional analog video output with the 600 TV lines.

Connecting monitors to the recorder (DVR)

After receiving signals from the analog cameras, the DVR can display them on a monitor or TV, just use the available BNC, VGA or HDMI outputs on the back.

Note in the following image that there is a BNC connector output to use a coaxial cable and connect to a traditional analog monitor and an HDMI type output to connect to a digital monitor.

Analog cameras with modern technologies

So far I have talked about traditional analog cameras that have the analog resolution measured in TV lines, the type of technology used in these cameras is called CVBS and is not the most appropriate to be used these days.

Modern technologies such as HD-TVI, HD-CVI, and AHD are suitable for CCTV projects where it is still necessary to use analog cameras.

When connecting a camera using this type of technology in a modern DVR, the digital output will be much higher than the 4CIF resolution (704 x 480 pixels) previously seen. It is common to find these modern cameras in the market with Full HD resolution (1920 x 1080 pixels) and even higher resolutions such as 3 Mega Pixel, 5 Mega Pixel, and 8 Mega Pixel.

When buying your CCTV cameras use this new type of technology.

Final words and conclusion

Analog CCTV systems are no longer used in large projects, as there is a preference for IP systems, but there is still a market for analog cameras and DVRs in small projects where cost is a key factor.

If you need to use an analog system, avoid the old traditional technology (CVBS) and use modern technologies with high-resolution analog CCTV cameras such as HD-TVI, HD-CVI, and AHD.

Connecting monitors to the recorder (DVR)

After receiving signals from the analog cameras, the DVR can display them on a monitor or TV, just use the available BNC, VGA or HDMI outputs on the back.

Note in the following image that there is a BNC connector output to use a coaxial cable and connect to a traditional analog monitor and an HDMI type output to connect to a digital monitor.

Analog cameras with modern technologies

So far I have talked about traditional analog cameras that have the analog resolution measured in TV lines, the type of technology used in these cameras is called CVBS and is not the most appropriate to be used these days.

Modern technologies such as HD-TVI, HD-CVI, and AHD are suitable for CCTV projects where it is still necessary to use analog cameras.

When connecting a camera using this type of technology in a modern DVR, the digital output will be much higher than the 4CIF resolution (704 x 480 pixels) previously seen. It is common to find these modern cameras in the market with Full HD resolution (1920 x 1080 pixels) and even higher resolutions such as 3 Mega Pixel, 5 Mega Pixel, and 8 Mega Pixel.

When buying your CCTV cameras use this new type of technology.

Final words and conclusion

Analog CCTV systems are no longer used in large projects, as there is a preference for IP systems, but there is still a market for analog cameras and DVRs in small projects where cost is a key factor.

If you need to use an analog system, avoid the old traditional technology (CVBS) and use modern technologies with high-resolution analog CCTV cameras such as HD-TVI, HD-CVI, and AHD.

DIY home security camera system installation (no monthly fee)

Installing a home security camera system yourself is not that hard. You just need to mount the cameras, run some cables and setup the video recorder. 

                                                           

In this lesson, I explain the basics of a DIY home security camera system installation, so purchase your kit and grab your tools to get started 

The installation is based on wired IP PoE cameras and a Network Video Recorder, which means is necessary to run UTP (network cables) from the camera to the recorder, but it's not necessary to use a power supply for each camera.  

==> For your reference you could purchase a security camera kit like the Reolink 4MP 8CH PoE Video Surveillance System available on the Amazon store.

==> Before go shopping, I recommend you to read the lesson: How to choose a security camera system for your home to have a better idea of the different types of system and choose the one that works for you.

How to install a security camera system

There are some steps you have to follow to have a good security camera system installation, please just pay attention to the details and everything will work fine.

Let's start with an example of wired security camera system installation.

Choose the best spot for the camera installation

Before installing the cameras is necessary to carefully choose the best spots that can give you a clear view of the subject you want to monitor and record.

Installation height

The cameras must be installed up high so they can't be reachable, you don't want people trying to break or change their position.

The security camera installation height is usually 3m or higher, which allows monitoring the area without compromising the camera physical security. 

Camera viewing angle

Choose the best position to avoid blind spots, check the viewing angle of your camera and mount it on the wall corner or other specific places to have the best angle that covers the entire area. 

Run the cables for the camera installation

In this lesson, I explain how to install wired security cameras, so you need to run the cables from the cameras to the network video recorder (NVR).

I highly recommend using an IP system so you can run fewer cables since the same cable that carries the video signal can also carry the power to the camera using the PoE technology (if you purchase a kit that has PoE devices).

==> Just in case you are interested in learning more about the PoE technology, please read the lesson: PoE switch for IP cameras. 

As you can see in the previous picture, the UTP cable (also know as network cable) must run from the Network Video Recorder to the IP PoE camera.

You can buy the network cables in any computer hardware store or even from an online store such as Amazon. Just look for UTP cat5e cables and choose the one that is long enough for your installation.

This type of cable needs an RJ45 connector at each side of the cable so it can be connected to the camera and to the recorder. You can either learn how to crimp the connectors or buy a UTP cable that comes with the connectors on each end of the cable (which is much easier if you have no experience with cabling).

See the picture below that shows the UTP cables that are sold with specific lengths, they are called patch cords and you can buy them with different colors. 

You just need to run the cables through the walls or ceilings from the network video recorder to your IP camera and drill the necessary holes.

Security camera installation

The camera installation depends on the type of wall you have and how you intend to run the cable. In this example, the camera is installed in a wood wall and the UTP cable goes through a hole behind it. See the picture below. 

In this picture it's possible to see a 3/4" drill bit that is used just in the center of the camera installation, that's large enough to pass the UTP cable.

As you can see it's possible to pass the cable through the hole even if it has an RJ45 already attached to it. Take those details into consideration if you are buying a pre-made cable (patch cord). See the picture below.

The next step is to mount the camera in its position, just use the screws that come with the camera (most of the models are sold with three screws). 

Just make sure you are using the correct screws for the type of wall you are installing the camera, if necessary just visit a hardware store to get new ones.

After installing the camera use a screwdriver to adjust the camera position.

Usually, you need to readjust the camera position after the setup is complete since it's necessary to look at a monitor to see where the camera is pointing to and what is the viewing angle. You can leave this step for later.

After installing the camera, just connect the UTP cable from the camera to the Network Video Recorder (NVR) as shown in the picture below.

The UTP cable is the same one you use to connect your computer or laptop to the Internet router, so it's pretty popular....

Security camera installation on the ceiling

The picture shows a security camera installed on a ceiling, note that it's not possible to see the cable since it's hidden (that's a nice installation).

The Installation diagram

It's important to understand how everything is connected to your IP security camera system, so just take a look at the diagram below.

As you can see, there's an IP camera connected to a recorder via the UTP cable which can carry the power using the PoE technology. 

Everything is connected to a router so it's possible to have local and remote access to the IP camera and to the NVR by using a mobile device, a computer or a laptop.

C'mon, just look at the diagram and tell me you can do such an installation.

It's not rocket science, you just need to purchase the devices, mount the camera in their position and connect the cables properly, the last step is the software and app setup and that's just a question of following the manufacturer instructions (read the installation manual). 

Other factors to consider

Light 

Make sure to have enough illumination where the cameras are installed and choose models that have infrared light for dark places monitoring.

Be careful when pointing your cameras to the area you want to monitor and avoid having them pointing to sources of lights, if you really need to have a camera installed in such a condition, look for models that can handle backlight with features such as BLC (backlight compensation) and WDR (Wide Dynamic Range).

When purchasing your camera, look for these features to guarantee you will have your security camera system working properly. See the information below with an example of a Hikvision IP camera which has the WDR feature.

If you need to install a security camera pointing to a door, windows or any source of light, you definitely will need a camera that can work with backlight compensation and the WDR is one of the best features for that. 

==> I recommend you to read the lesson: What is WDR (Wide Dynamic Range) for CCTV cameras to better understand this technology.

The problem with dark areas showed in the previous picture can be solved with the use of this technology, so considering using it.

Conclusion

With this DIY home security camera system installation, you can have everything working and avoid the monthly fees charged by security companies.

I recommend you to read the product manual and follow further instructions on how to setup the system for remote access with a mobile phone.

Usually, it's a very simple process just like the one you can find in the lesson How to access Hikvision DVR from mobile, just use the same principle for your system.

I hope this information can help you with your DIY installation.