CCTV SYSTEMS WIRELESS BASED CCTV
CCTV SYSTEMS • Wireless security cameras transmit a video and audio signal to a wireless receiver through a radio band. • Many wireless security cameras require at least one cable or wire for power; "wireless" refers to the transmission of video/audio. • However, some wireless security cameras are battery-powered, making the cameras truly wireless from top to bottom
CCTV SYSTEMS • Wireless cameras are proving very popular among modern security consumers due to their low installation costs (there is no need to run expensive video extension cables) and flexible mounting options.
CCTV SYSTEMS • Wireless cameras can be mounted/installed in locations previously unavailable to standard wired cameras. • In addition to the ease of use and convenience of access, wireless security camera allows users to leverage broadband wireless internet to provide seamless video streaming over-internet.
CCTV SYSTEMS • Microwave communication is used for large installations and is used to communicate between buildings and other locations.
CCTV SYSTEMS • Microwave antennas used for this purpose require FCC licensing because they use parts of the radio spectrum that are regulated. • Microwave transmission requires at least a near line of sight (NLOS) and can transmit signals up to 21 miles, atmospheric conditions will affect transmissions.
CCTV SYSTEMS • Microwave communication operates in the 900mhz range (portable telephone), 2.4ghz range (Wi-Fi) or the newer 5.4ghz ranges.
CCTV SYSTEMS • Infrared (IR) uses light as a means of transmission. • Commands are encoded at the transmitter and pulsed from a special light emitting diode (LED) to a receiver unit. • IR links are strictly line of sight (LOS) with a transmission distance of approximately 700 feet
CCTV SYSTEMS • You cannot signal IR around corners or with an obstruction between the transmitter and the receiver.
CCTV SYSTEMS • Infrared links are typically used to establish links between buildings on the same campus, guard shacks or to cross a busy street where installing a cable would be cost prohibitive. • These IR links are also affected by inclement weather like fog and heavy snow fall.
CCTV SYSTEMS • RF wireless camera systems utilizing Wi-Fi frequencies is the most popular wireless system in use today. • They’re fairly easy to implement and can be added to an existing hard wired system essentially creating a hybrid CCTV system.
CCTV SYSTEMS • The limited number of frequencies available is disadvantage when designing a system using wireless cameras. • Most wireless camera are limited to 3 different frequencies. • This means that you are limited to using four cameras at one location per frequencies range.
CCTV SYSTEMS • Analog wireless is found in three frequencies: 900 MHz, 2.4 GHz, and 5.8 GHz. Currently, the majority of wireless security cameras operate on the 2.4 GHz frequency.
CCTV SYSTEMS • Most household routers, cordless phones, video game controllers, baby monitors and microwaves operate on the 2.4 GHz frequency and may cause interference with your wireless security camera. • 900 MHz is known as Wi-Fi Friendly because it will not interfere with the Internet signal of your wireless network.
CCTV SYSTEMS • Cordless phones operate on the 900MHz frequency and there are cordless phones that operate on the 2.4GHz and 5.8GHz frequency too. 900MHz 2.4GHz 5.8GHz
CCTV SYSTEMS • The limitations and interference issues of the RF band used by wireless cameras has to be taken in account when implementing a wireless CCTV system. • Residential installs will be affected by all of the other consumer electronics that will interfere with wireless cameras, however wireless is better suited for residential environments because it addresses the cabling challenges.
CCTV SYSTEMS • Distance limitations also have to be taken into account when implementing a wireless solution. • Cameras can’t be placed too far from the DVR and line of site though not entirely necessary will provide a much better link. • The same limitations that affect a wireless router are also true for wireless camera systems.
CCTV SYSTEMS • What do you think is the maximum operating range of a wireless camera? • What do you think is the maximum operating range of a wireless camera that isn’t in line of sight to the DVR? 500 feet line of sight Half the distance
CCTV SYSTEMS • It should be noted that the 500 foot distance is a perfect world scenario, most systems are limited to about 300 feet. • When you account for obstructions such as walls any quoted distance will be cut in half and in some cases less than half.
CCTV SYSTEMS • What type of obstruction will limit the wireless signal the most: a sheet rock wall, a block wall, a sheet rock wall with mirrors or a ceramic tiled wall? A mirrored wall reflects signals and will easily block wireless signals.
CCTV SYSTEMS • Here is the back of a wireless camera, notice that it has dip switches like a PTZ camera, these are used to set the camera ID.
CCTV SYSTEMS • The back of a wireless DVR, notice the antenna connections are SMA, this is the defacto standard for most wireless devices in the Wi-Fi industry.
CCTV SYSTEMS • The front of the DVR with the antennas installed, with exception of the antennas the DVR has the same look and feel of a hardwired DVR with all the same controls and interfaces.
CCTV SYSTEMS • The only other function on a wireless CCTV system is the pairing button, the DVR will provide a message that tells you to press the pairing button on the camera. THE DVR SCREEN SHOWN ON THE MONITOR BEFORE PAIRING
CCTV SYSTEMS • When the pairing button is pressed the DVR will link with the camera and provide the camera image when successfully paired. IN THIS CASE CHANNEL 2 HAS PAIRED WITH THE DVR.
CCTV SYSTEMS • If you want to add a wireless camera to an existing CCTV system a wireless transmitter and receiver will have to be installed.
CCTV SYSTEMS • The wireless transmitter and receiver are labeled with TX and RX respectively.
CCTV SYSTEMS • Which unit do you think goes to the camera end and which unit is installed at the DVR? TX AT THE CAMERA RX AT THE DVR
CCTV SYSTEMS • Remember that each wireless camera or wireless transmitter will require power. • The transmitter and receiver operate on 5VDC and 1A. • Most wireless cameras operate on 12VDC and 350mA to 500mA.
CCTV SYSTEMS • Battery power packs are available for wireless solutions like the one you saw in the power supply lecture. • How can you increase the distance of a wireless transmission in a wireless CCTV system?
CCTV SYSTEMS • Wireless CCTV systems use the typical rubber duck antenna with SMA connectors that is rated at 3dBi, you can replace the antenna with a higher gain omni-directional or a higher gain directional antenna. 5dBi 7dBi 10dBi DIRECTIONAL