All About Wireless Security Cameras   by Scott Watkins

A wireless security camera can be used in various applications where a wired camera is not practical for surveillance and monitoring. They work by transmitting a video and (sometimes) audio signal to a remote monitoring station using radio frequencies. Power for the camera is provided by either plugging in to a convenient power jack, although some models are powered by batteries ,or by solar panels.

Early Wireless Security Cameras

These analog cameras send an "analog" video signal to a receiver, which is then connected to either a television monitor or a recording device, such as a video tape recorder, or digital video recording system (DVR). A majority of these cameras and systems use the 2.4 GHz frequency, which is the same band used by many other wireless devices, like cordless phones and even computer networks. It's possible that these various systems can interfere with each other when in use.

The advantages of analog wireless security systems is they are lower cost than their digital brethren, and you can use multiple receivers.

The disadvantages are they may cause interference with other devices in the home. The transmission is not secure. the video signal quality is lower than digital, and any interference makes it worse.

900 MHz systems can be used in installations where the signal must go through drywall or even trees to reach the receiver. There is also not a lot of interference with other devices. Unfortunately there are only two channels available at 900 MHz.

2.4 GHz systems are more common, and there are 12 channels available, however, it is rare that you can find a channel that is not already in use by another wireless device.

5.8 GHz setups have a better chance of success, since there is less interference and there are 8 channels available (so you can have up to 8 cameras). The biggest challenge is the signal cannot go through many walls without lots of degradation.

Transmission Power

Lower cost 5.8 GHz systems most likely have a 10 milliwatt transmitter, which ideally can transmit to 300 feet with line of sight between the transmitter antenna and the receiver antenna. This rarely happens. This is a broad generalization and conditions such as distance, weather and clear line of sight affect this greatly.

When selecting an analog wireless security camera system, make sure you find out the transmission power and determine whether this will be enough to overcome any obstacles in your system.

Digital Wireless Security cameras

A digital security camera converts the video information to a digital signal, which is then sent to a compatible receiver.

Some of the advantages of this type of system are:

The range of transmission of the signal is as much as 450 feet with line of sight between camera and receiving station
The quality of the signal is very good
Two-way communication between camera and operator if required
It is difficult for others to capture the radio signal and interprets it, using modern digital security methods

Wireless IP Security Camera

Wireless security cameras are now available that can connect through a local area network over commonly available wireless systems. Essentially, these cameras become a "web page" with their own unique IP address. These include 2-way audio feeds, encryption, pan, tilt control and automatic night vision. Because of the popularity of wireless networks, you will find more and more of these cameras being used in security camera systems