Posts Tagged ‘ coaxial video transmission cable ’

Wireless Outdoor Security Camera Systems

Tuesday, January 4th, 2011

A wireless outdoor security camera system can be used for many different applications. The system is easy to install, easy to operate, and incredibly versatile in application. Since the wireless outdoor security camera does not require a video transmission cable to be run from each camera to the Digital Video Recorder or DVR, you may want to consider this system if cabling the system is impractical, undesirable, or simply can’t be done.

Standard standalone digital video security systems have three major components: 1) One to several digital video cameras; 2) A Digital Video Recorder or DVR; and, 3) one or more color monitors. The digital video cameras capture light images and turn them into electronic data that is sent to the DVR. The DVR creates a digital video file that can be viewed that instant (live) on the monitor and/or stored on the DVR for later viewing, archiving, etc.

These systems are connected by the use of various wires and cables. For instance, each digital video camera must have a coaxial cable run from the camera to the DVR unit. This video transmission cable is usually RG-59 type coaxial video transmission cable. It carries the video data from the camera to the DVR unit to be processed. Each camera also must have a smaller low-voltage DC wire run to it from either a power distribution supply box or a nearby plug-in transformer.

Wireless outdoor security camera systems eliminate the need to install the digital video transmission cable. Instead of using RG-59 coaxial cable the camera sends its video data to the DVR by radio wave signals. This is normally done in one of two ways. Either the camera sends its radio signal to a corresponding receiver which is located near the DVR unit and connected to it by cables, or the DVR unit itself has on-board receivers that the camera broadcasts its signal to.

The camera of a wireless outdoor security system may not be entirely wireless. Although there is no need to run the RG-59 coaxial cable in these systems, the cameras still require a power supply which is normally provided by the power distribution center box or a nearby plug-in transformer. However, there are cameras that are battery operated, using either one-time-use or rechargeable batteries. These cameras are truly wireless in that they have no video transmission cable or power supply wires run to them.

Since outdoor security camera systems do not require video transmission cabling, they can be much quicker and easier to install. Mount the camera, plug it in, and it’s ready. Even easier to install are the battery operated cameras; just mount the camera (no need to run a power supply wire) and it’s ready to go.

Wireless outdoor security camera system cameras use various technologies to send their radio signals to the designated receiver or DVR. One of the most popular methods that is used is the 2.4 or 5.8 MHz technology; this is the same technology used to send land-line based cordless telephone signals. It’s useful for this purpose because the signal is strong and virtually interference free.

It is important to note that the camera-receiver (or DCR with built-in receiver) relationship on wireless outdoor security camera systems have different specified ranges. Not all cameras have the same range. In fact wireless cameras may have a manufacturer’s specified range of from 30 feet to 2 miles Line Of Sight or LOS. LOS means a direct path in a straight line from camera to receiver that has no objects blocking the path. In other words, if you are standing at the point where the camera is mounted, you should be able to see the receiver (i.e. LOS).

Although the range is specified as LOS, it doesn’t necessarily mean that an impeding object along the path will prevent reception. In fact, seldom is the reception actually blocked by impeding objects; normally the range is just reduced. The reduction of the range is variable based on the transmission signal technology used and the material make up of the object(s) that fall within the LOS. Windows have less effect that walls or trees for example. This is not unusual as cordless telephones share this same sort of LOS range. Therefore, be certain the specified range of the camera satisfies your requirements before purchasing the camera or system.

Other than the need for replacing or recharging batteries, the cameras in a wireless outdoor security camera system or relatively maintenance free.


Digital Video Recording System

Wednesday, November 10th, 2010

The digital video recording system is rapidly becoming one of the most popular security and surveillance documentation and monitoring tools in use today. Thanks to advancements in digital technology, not only is high-quality color digital video possible, but its also economically priced, easy to install, and versatile in application.

A digital video recording system is any system that captures digital video images and records them on some type of storage medium for later use. The difference between a digital video recording system and an analog video recording system is how the video image signal is created; however this lends itself to other differences such as how the video “footage” is stored, how it is transmitted, and what kinds and types of images are available.

First, let’s look at how an older analog video recording system works, then we’ll compare it with the newer digital video recording system. Both systems have a camera that “captures” the video images and a recorder that stores those images for playback at a later time. Each system may also use monitors to display real-time (live) video as it is captured.

Without getting too technical, an analog digital video camera contains a sensor chip called a Charged Coupled Device or CCD. The CCD converts the image’s light energy, which is focused onto it by the lenses, into electrical energy that can be measured and used to create a video image. The images are transferred from the camera to the video recorder and monitor using a coaxial video transmission cable.

The analog video recorder records the audio and video as magnetic signals, usually on a magnetic tape. What is actually happening is that the camera is taking several pictures per second but it appears to the human eye as smooth motion video. This is the same way its precursor, film video works.

Film cameras actually take several film pictures or photographs per second. Once the film is processed or “developed” a projector rolls the film from the full reel to an empty one. As the pictures pass in front of the projector lens in rapid succession, they give us the impression of a moving video. Since film is basically a linear storage device that can be hundreds of feet long, the term “video footage” was used to refer to motion pictures.

Since analog video is stored as a magnetic pattern, each time the recorded video is played it has the potential for degrading the signal. In addition, time can also degrade the magnetic signal as the signal’s weaker points can fade. Analog video is stored on a variety of formats but the most popular magnetic video tape is VHS or BETA. The video recorder either uses a video tape loop that re-records after reaching the end of the tape or individual video tapes that must be replaced when the recorder reaches the end of the tape.

Digital video recording systems use basically the same technology to create digital video. Cameras record (with the advent of digital imagery, the term “record” is also used synonymously with “capture”; meaning that the camera “captures” light images) image light energy and transfer it into electrical energy. However, the fundamental difference in a digital video camera is that the camera also contains an analog-to-digit converter which turns the analog video signal into a series of 1s and 0s, or in other words, digital data.

This simple change has revolutionized the security camera industry. Since the digital video signal is now stored as a digital file, many other technological changes have taken place that have made digital video recording systems differ from their older analog parents. Here are some of the differences (some are more advantageous than others) of using digital video recording systems:
• Personal Computers can now be used to control and record the cameras;
• Standalone digital video recording systems save their data to Digital Video Recorders or DVRs that have the potential for storing thousands of times more data in the space of an analog medium;
• Cameras can be networked, controlled, and monitored using the internet;
• Components of the system are smaller, lighter, and more efficient using less energy;
• Digital signals are 1s and 0s – they do not fade or degrade like analog signals can.

Digital video recording systems have become so popular that they are now the norm in the security video industry, rather than the exception. If you are interested in learning more, check out Security Camera King’s “CCTV Learning Center.”


Wireless 16 Camera Motion Detector Security Surveillance

Tuesday, October 12th, 2010

Wireless 16 camera motion detector security systems are capable of providing total video security for any residence or business. These systems make installation a cinch and in addition conserve on system resources. In addition, these systems are incredibly versatile, especially when utilizing optional features.

Generally, the brain or heart of a video security system is the Digital Video Recorder or DVR. The DVR normally contains a specialized computer processor that is designed to perform the tasks necessary to create and store digital video files and coordinate and control digital video camera functions. For a wireless 16 camera motion detector security system only one DVR is required, although it is possible to create 16 camera systems using a variety of DVRs with lower camera input capacities (such as two 8-camera DVRs).

Since “wired” camera security systems must have a coaxial video transmission cable run from each camera to the DVR the only determining factor for the number of cameras used in the system is the number of video inputs that can be handled by a DVR (Usually 16 is the maximum. Systems requiring more video inputs than 16 usually utilize more than one DVR.)

However, the single most determining factor for a 16 camera motion detector security system is how the cameras’ wireless video signals are handled. Each camera must have its own unique frequency or channel on which to transmit its digital video signal. It’s important to pause here for a minute to discuss the use of the term “channel” as there is some ambiguity involved with the use of the term in the realm of video security.

Most of us would probably think of a channel as a specific frequency, such as a television channel or radio station channel which is one way the term is used in the industry. For example, a wireless camera may transmit on 921.103102 MHz which, for the sake of this discussion, we will call channel 1 or 921.205012 which we may call channel 2. That’s one security camera industry definition for “channel.”

However, often times “channel” is used to reference the number of video and/or audio inputs a DVR or receiver can utilize. In this instance a 9 channel DVR would be able to accept inputs from up to 9 different video cameras also called “channels.” For example the most common DVR units are four, eight, and sixteen channels.

Getting back to our discussion of wireless 16 camera motion detector security systems, these systems would normally require a 16 channel (camera input) DVR. They would also require 16 wireless cameras each on a different channel (frequency). The key factor for these systems would be:
1. Acquiring 16 cameras each transmitting on a different frequency; and,
2. Determining how to receive these signals.

This could be done in a variety of ways ranging from using multiples of receivers that total a video output to the DVR of a total of 16 individual video channels, or using multiples of DVRs that total 16 individual video channels or inputs with each camera input using a different frequency (also referred to as a channel). In addition, modern technological advances have produced IP or Internet Protocol ready cameras that contain their own web server technology. Sixteen of these cameras could theoretically be used to create a wireless 16 camera motion detector security system as well.

In these systems, each of these cameras have a built in PIR or Passive InfraRed sensor. These sensors can detect a change in infrared transmission, such as that caused by a moving object. The PIR sensors are normally connected to a relay that switches the camera video transmission on when motion is detected. The camera stops recording either after a predetermined programmed time period or when the motion detection ceases.

A motion detector operated camera offers several potential benefits that include:
• Conservation of DVR disk space since video is only transmitted when motion is detected;
• Conservation of power usage which is especially important if the cameras operate on battery power; and,
• An alerting function since the cameras only record if motion is detected (For example, some IP ready cameras or DVRs can send an email when the camera has been triggered “on.”)

In addition, wireless 16 camera motion detector security systems may be purchased with optional features such as day/night, Pan-Tilt-Zoom (PTZ), object tracking and many other options, all of which contribute to making these systems one of the most versatile video camera security solutions available today.