First Generation Wireless Video Security Cameras
Early “analog” cameras transmit the video signal to a receiver, is usually then hooked up to either a television monitor or perhaps a recording system, such as a video tape recorder, or digital video recording system (DVR). Note that most of them operate over the 2.4 GHz band, the same band that a lot of other household wireless appliances, such as cordless phones and video game controllers, operate on. Additionally, microwave ovens operate at 2.45 GHz, and radio controlled toys also use the 2.4 GHz band. Thus, interference may result if you use these older cameras where other wireless household equipment are in use. These other devices can cause image-degrading interference with your security system.
There are advantages of analog wireless cameras:
* They fit most budgets;
* Multiple receivers can be used with one camera;
* The X10 protocols allow use of multiple cameras with a single receiver;
* Virtually anyone can install these cameras. You can have a wireless video security system operational very quickly, and at low cost.
The disadvantages of analog wireless cameras:
* They may cause interference with other devices in the home;
* Non-secure transmission can be intercepted and viewed by others;
* Signal quality is dependent upon many external factors which make it susceptible to interference.
Cameras using the 900 MHz band are best used when there is no line-of-sight between the camera and the receiver. The downside to these is that there are only two channels, so you can only have 2 cameras in your system.
You can have 12 cameras when you are using 2.4 GHz versions. The biggest challenge is interference with other appliances that use the same frequencies.
Newer 5.8 GHz cameras will encounter less interference. Operating at this frequency allows for 8 cameras in your system. The signal is easily degraded by physical objects, so only use it when there is a relatively clear “line of sight”.
Transmission Power = Distance
Transmission power is important. The less “line of sight” of your system, the more power you need..
Low cost systems have less power. though you will see advertisements of 300 feet line of sight transmission. It’s rare that this happens. Environmental conditions such as distance, weather and clear line of sight affect this greatly. It’s harder for the short wavelength 5.8 GHz signal to pass through barriers than it is for 900 MHz or 2.4 GHz transmissions.
Wireless Security Cameras Using Digital Signals
Newer wireless cameras generally are digital. The video signal is first digitized, and then transmitted in packets to a receiver. Most digital wireless cameras use the 2.4 GHz band for transmission. These cameras are much more tolerant of interference.
The transmitter is usually around the same power level as a wireless router, around 16 dBm.
Why Digital Is Better Than Analog:
* Transmission range up to 450 feet (line of sight);
* Very high quality images and sound;
* Allows two-way communication;
* The signal can be encrypted, for high security.
Networking A Wireless Security Camera
Wireless IP cameras can be used to connect to your LAN. An IP camera is viewed in a browser window. All you need to know is the IP address, and sometimes a security login.
Some of the features of these are aiming control, night-vision illumination, encryption, motion detection and more. Because of the popularity of wireless networks, you will find more and more of these cameras being used in security camera systems.
To read more about wireless camera surveillance
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Scott Watkins is a retired Electrical Engineer now writing on a variety of topics, including ccd camera housing
, health and fitness, model railroading, and more.
