Posted by Arowosegbe Olawale in General

The advantages of wireless video transmission include reduced setup time, no need for cables, and worry-free portability. Wireless systems have a few drawbacks, including signal disruptions, interference, and the need for a specific frequency to transmit signals. The need for stronger information assurance measures is also growing in response to rising cyber security concerns. 

4.2.1 Laser

Video transmission cables can be a hassle to set up in certain situations. Laser or infrared transmission can be used if there is a clear line of sight between the sending and receiving locations.

Laser transmission has many practical uses, and it has many advantages over wired transmission. Here are some benefits of using a laser transmission system:

• The ability to transmit from 20 metres to 2 kilometres in ideal conditions
• Transfer rates between 25 MB and 1.2 GB of data per second
• Ability to accommodate horizontal and vertical misalignments of up to 2.4 degrees (especially helpful for swaying towers);
• Mounting options for the interior that are invisible from the outside;
• Safety Class 1M (naked-eye visibility) according to the International Electrotechnical Commission;
• There are no problems with ground loops, lightning, or induction;
• That there is no need to obtain a license or permit;
• Almost impossible to tap into covertly.

There are some drawbacks to lasers as well. To avoid the risk of retinal injury, lasers shouldn't be used in public places. Furthermore, the distance between the transmitter and the receiver, as determined by laser transmission, is affected by weather. Signal alignment and line of sight are mandatory. These newer laser systems are more resilient to environmental factors like fog and snow thanks to their narrow beam and auto tracking capabilities. A brief interruption is always possible, but retransmission can happen automatically.

4.2.2 Infrared

A transmitter with an infrared LED is an alternative to a laser. While infrared LED systems may be less expensive overall, laser systems typically offer greater throughput and greater transmission range. Reflections are another problem for LED systems, especially when trying to transmit through glass. A common mistake is to point an IR receiver directly at the sun, an incandescent bulb, or another IR source. You should know exactly what you'll be using the IR LED transmission system for, and where you'll be installing it, before even considering it.

4.2.3 Radio Frequency

A second form of wireless transmission that has practical application in CCTV is radio frequency (RF). Video signals are typically modulated using radio frequency (RF) in cable TV systems operating in the UHF and VHF spectrums. The term "radio frequency" (RF) describes a wide range of audible frequencies.

Focused beams are used for transmissions, and they perform best in clear, line-of-sight conditions. A radio frequency video signal can be weakened by obstacles like walls or buildings.

When it is not feasible to run cables or rent a high-bandwidth line, RF systems are often used as an alternative. There is a common misconception that RF transmission systems have a limited range. By using directional antennas and repeaters, RF CCTV transmission systems are capable of reaching great distances. When using a flat antenna array, radio frequency (RF) transmission range is roughly 2 miles, while directional antennas can increase this to 7 miles. In Figure 4-3, you can see several examples of various antennas.

4.2.4 Microwave

Similar to laser and LED systems, microwave transmission is a line-of-sight, wireless transmission medium. Video, audio, and data can all be transmitted via a microwave system, but only if the system is set up correctly. When investigating microwave transmission, it is important to think about the following.

Transmissions can be made from as close as 100 feet to as far as 20 miles, with the help of microwave repeaters; 

Microwave transmitters may need FCC licencing; Microwave transmission is more resilient to environmental factors and physical obstacles than laser transmission. 

Microwave transmissions are typically unaffected by weather conditions, though extremely heavy rain and dense fog can cause interference; 

Microwave systems emit at low energies, typically less than 1 milliwatt per square centimetre (mW/cm2). 

Microwave systems tend to be more expensive than LED or laser systems, while the American National Standards Institute's recommended minimum safe radiation exposure level is 10 mW/cm2.