Video systems are becoming a part of our everyday lives. When video surveillance systems first hit the market in the mid 80's, they immediately developed a major impact on crime prevention and exactly how crimes are investigated. Early video systems required a hardwired connection involving the camera and the recording system. Recent innovations in wireless video transmission are changing that requirement.
Wireless video systems are popping up all over the place to satisfy a range of consumer requirements. From wireless baby monitors to high-end high-definition wireless broadcast systems, wireless video systems can be found in a wide range of prices, functions.
Most modern, consumer grade wireless video systems will belong to one of the following frequencies; 900 MHz, 2.4 GHZ or 5.8 GHz. Almost all of the affordable consumer grade wireless cameras on the market fall into the 2.4 GHz range.
Every wireless video system consists of a camera, a transmitter, a receiver, an antenna along with a power supply. Transmission ranges can differ greatly depending on the frequency, the antenna as well as the rated power output.
Except for higher end, high power broadcast quality systems; most wireless video systems do not require a license from your Federal Communication Commission (FCC) to work. No matter what frequency you plan on using, in case you are installing a high powered installation, especially near a highway or an airport, you should secure the right FCC license.
For the best results as well as the longest range, most wireless video transmission systems demand a clear line of site involving the transmitter and the receiver to work consistently. Wireless video signals don't penetrate very well through glass, walls, concrete, trees, steel or another obstructions.
In addition, other RF signals round the same frequency may cause interference or be interfered with by wireless video systems. Within the 2.4 GHz range well-liked by most security applications, interference can be experienced between cordless phones, microwave ovens, local television broadcasts, computer monitors, power supplies or wireless LAN/WANs. Sometimes interference problems can be solved by re-locating the transmitters or receivers.
Since 90% of consumer grade wireless video systems belong to the 2.4 GHz category, we'll discuss the features of both 2.4 GHz digital and analog systems and the limitations and advantages of each.
The entire 2.4 GHZ bandwidth allocated for consumer me is from 2,412 MHz to 2,462 MHz. As per the FCC standards, you will find 11 possible channels which are 22 MHz wide with a 5 MHz spacing interval between each.
In order to allow multiple cameras for a passing fancy system, residential, consumer grade 2.4 GHz analog video transmitters for instance a wireless baby monitor or perhaps a front door camera require fixed frequency, non-overlapping channels to reduce interference.
These 2.4 GHz analog wireless cameras are some of the most popular video surveillance systems for consumers and end users, yet very few professional security providers will give you these wireless cameras.
At best, professional security installers look at the 2.4 GHz analog video systems as low-end residential solutions which are notoriously unreliable. The analog 2.4 GHz cameras are easily identified by their cost which is usually in the $ 69.00 to $ 140.00 range per camera.
If you take away the benefit of their low priced, there are several inherent limitations to Analog 2.4 GHz video transmission including:
Within the 2.4 GHz range, you will find only 4 available non-overlapping channels. This limits these systems to a total of 4-cameras, each of which is tuned to a different pre-defined frequency. Each of these fixed frequencies is capable of transmitting about 11 mega-bits per second of information (Mbps).
Because the analog 2.4 GHz wireless video transmitters are on fixed frequencies, they are especially susceptible to interference from outside sources. A typical transmission range with an analog 2.4 GHz wireless video link is about 200 to 300 feet when installed outdoors with a clear line of site. The relative transmission distance is cut down tremendously when installed indoors with a few lower end analog systems typically providing about 10-30 feet.
Since these cameras are transmitted on the fixed, un-secured open frequency, the signal is definitely intercepted and can be seen by anyone with a 2.4 GHz 4-channel receiver. A voyeur or perhaps a burglar could simply drive around a neighborhood with a receiver and see in your home. If you have one of these systems installed, perhaps a burglar is watching you at this time.
In 1997, the Institute of Electrical and Electronics Engineers (IEEE) came up with first Wireless Geographic area Network (WLAN) standard which was named 802.11. The original 802.11 utilized both the.4 GHz frequency to allow reliable transmission of 2-Mbps of bandwidth. In 1999, the standard was upgraded to 802.11b which supports up to 11 Mega-Bits per Second (Mbps) which was comparable to traditional Ethernet connectivity speeds.
The 802.11 protocol functions by sub-dividing the entire 2.4 GHz frequency into channels and switching bewteen barefoot and shoes during transmissions. As the signal is sent, it sends a packet of information at one frequency after which hops to the next channel and sends another packet and so on, until the entire data package is shipped.
In 2003, WLAN products began supporting a brand new 2.4 GHz wireless standard called 802.11g which supports a bandwidth of 108 Mbps of information. The days of affordable, reliable and secure wireless video transmission have finally arrived.
The added features and benefits of using internet protocol cameras and 802.11g for wireless video transmission in a security application are many.
The 802.11g protocol utilizes digital bi-directional signals which keep the use of pan/tilt/zoom functions and presets found in many newer cameras. The digital signal used is duplex (bi-directional) as opposed to the simplex (one-way) binary signal used in analog type systems.
Because 802.11g utilizes the entire 2.4 GHz frequency spectrum, interference is cut down tremendously and longer transmission ranges should be expected. If an area of the frequency is noisy then the transmitter/receivers will adapt the signal by sending smaller packets in the noisy affected area and larger packets in the non-effected areas of the frequency. A wireless IP video system will give you almost the same performance as a professional grade wired system with a reliable transmission range of 150-200 feet.
If the camera is to be located further than 200 feet, directional antennas are available which can increase the distance to 600 or more feet. If a greater distance than 600 feet is required, point to point, long range directional type systems can boost the distance to several miles.
Along with standard 64/128-bit WEP Security, 802.11g protocol allows data packets being encrypted using a 40-bit RCA key. When considered in conjunction with the inherent security built into DSSS spread spectrum technology, the information signals are at least as secure as data traveling over a wired network.
The 802.11g protocol supports a much larger number of wireless cameras simply by using a medium access control or MAC layer called CSMA/CA or Carrier Sense Multiple Access/Collision Avoidance. The collision avoidance in 802.11g supports the use of CTS/RTS signals (clear to send/ready to transmit) which tell each camera about the system when it is O.K. to start transmitting or receiving data thereby avoiding interference.
Any hardwired IP Camera which is installed on your intranet or internet which is using the same CODEC (Coding & Decoding) algorithm can be integrated into the same software viewing and recording system.
An IP addressable camera system can be seen or recorded from a properly equipped computer from the location in the world. This could allow you the freedom to maneuver anywhere on the planet while still checking your assets. Additionally, if you ever decide to move your mind end recording equipment to a different location, you simply get it and move it. No wires to re-route.
Think about remember when deploying a multi-camera wireless IP based video method is that processing multiple streaming video signals places a substantial work load on a computers CPU.
Wired systems have video capture cards which are installed in the PC/DVR. Prepaid credit cards take up to half of the task load off the computers CPU. Because wireless IP video systems do not have the help of these capture boards, the computers CPU must handle 100% with the processing workload.
This implies that as you add cameras to a wireless system the total frame rate or even the total images per second which can be viewed and recorded will decline because of the increased workload.
Many people shy away from IP and network security solutions simply because they appear to be complicated and difficult to set up. The fact is the first set up does require some expertise and data but the operation and daily use of the systems aren't any different than using some other PC based home security camera system. The required computer skills are minimal. If someone can check email, work with a word processing program or load and play any sort of game on a PC they probably possess the skills necessary to use and manage your personal computer based system.
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