Wireless technology has largely replaced wired communication systems in just about every imaginable field. It’s what makes mobile phones and signals bouncing off your router a possibility. But the internet and mobile telephony are just the tip of the iceberg where the principles of wireless communication have been implemented. Less obvious are the complex systems of industrial control and monitoring processes, that until recently relied on hard-wired systems, consisting of cumbersome lengths of cables and controls units. Going wireless has reduced costs for many businesses, simplified operations, increased functionality, and put security at the forefront.
In the specific industrial context, wireless was first used in automated guide vehicles and cranes in warehousing applications. Various wireless technologies however have found their way into other areas, simply because they overcome the typical shortcomings of wired communication systems – limited range, cost, maintenance overheads, and where cables and installation are difficult or impossible. For controlling different equipment and systems, wireless has also proved both safer and more convenient.
Wireless tech is simple to implement into existing systems and infrastructure. Having a basic understanding of the equipment involved and how it works helps in choosing what’s right for your business.
What is Wireless?
Wireless is a mode of communication that permits the transfer of information between two or more points without the use of wires or cables. The principles of wireless were first established by German physicist Heinrich Hertz with the discovery of electromagnetic waves in the late 1880s. Waves are created from energising a piece of metal (for instance an antenna) and travel to distances depending on the strength of the induced energy.
Signals or electromagnetic waves are transmitted from a wireless transmitter at a set frequency and picked up by one or more receivers. Wireless communication then involves the use of a wireless audio transmitter and receiver. From the onset of radio and television in the first half of the twentieth century to the introduction of 5G networks beaming billions of pieces of data each second, wireless has transformed society and provided new possibilities both for individuals and businesses.
Types of Wireless Signals
Wireless signals don’t encompass a single category. Instead, there are different types. AM and FM signals for radio, VHF and UHF for terrestrial TV, cellular in mobile telephony and Wi-Fi and Bluetooth in almost every gadget and device in use today. And they all differ in frequency. The unit for frequency is Hertz (Hz) or how a signal changes each second. Signals that vibrate slowly are said to have a low frequency, like AM radio signals, and those that vibrate quickly are said to have a high frequency, for instance, 5G. AM waves vibrate in a frequency range of 540 to 1700 thousand times a second or kHz, whereas 5G signals are transmitted at 24-39 billion times a second or GigaHertz (GHz). These two types of signals form the lower and higher ends of what are called radio frequencies.
Besides having different frequencies, waves are also different in how they convey data, or more specifically, in modulation. This essentially is how waves are modified in order to transmit information. One simple example is the difference between Amplitude modulation, or the strength of the wave in an AM signal, and Frequency Modulation in an FM signal. The two are incompatible with each other. The same can also be said of terrestrial analogue TV and digital TV signals, and why your 4G phone won’t work on a 5G network.
The Equipment – Receivers, Transmitters and Antennas
Devices that transmit wireless signals are called transmitters, and those tasked to receive them – are receivers. For instance, an FM radio station can transmit signals from one transmission station to thousands of radios, or receivers. The opposite is also true, but not as common. An example is a wirelessly operated gate that can be opened and closed by a receiver receiving signals from one or hundreds of transmitters or remotes operated by as many different people. Systems with a wireless audio transmitter and receiver are also used in other access control units, typically in doors, but also in home automation, security systems, automated lighting, controlling various automotive systems, and more. Receivers and transmitters used here work on a UHF frequency of 433 MHz, and the short wavelength is less prone to interference with signal strength remaining stable.
Units that incorporate both a transmitter and receiver are called transceivers. You’re probably reading this from a transceiver or mobile phone, or signals are received and beamed from your home or office router. Both devices require an antenna to get signals to the required distances. There are different kinds of antennas. Routers for example have omnidirectional antennas, with signals spreading in all directions, but losing strength with distance. Signal strength is substantially better in directional antennas (either a sector or focussed antenna) and these are what you’d find in most remotes used to operate wireless systems like automated gates mentioned above. Signals also suffer from less interference and can travel longer distances with less power.