Understanding the Key Technical Aspects and Performance of Digital and Analogue Two Way Radio

In recent years the introduction of 'digital' two-way radios has added a whole new range of radio equipment and capabilities to the two-way radio market, but at the same time it has also added another layer of complication to the procurement/buying selection process, which many customers find it difficult to understand and interpret. General managers, Facilities managers, Security managers and other key buyers have a significant responsibility to ensure that they get the 'right' equipment with the best suitability and functionality to suit the current and future needs of their organisations, and of course to get value for money! This article aims to help clarify but one of those decision criteria - whether to go for a digital or an analogue two way radio system.

The use of the term Analogue to describe two way radio communications usually means that the information being conveyed (what the user has spoken into the microphone) modulates the carrier signal (simply put it superimposes your voice upon the transmission on the stated 'carrier' frequency). The carrier signal travels through open space as an 'Electro-magnetic wave' and that wave reaches a certain distance or range depending on the frequency, the power and the intervening ground and environmental conditions. Sometimes in challenging conditions or over extended distances the signal becomes weak and difficult to hear. This is the limit of the range for that unit and the signal becomes very noisy and difficult to understand.

By contrast in Digital communications, the information being conveyed (again probably the users voice through a microphone) is converted into a stream of binary code. The modulation of the carrier signal on this occasion is limited to transmitting a series of 1's or 0's which are converted back into your voice at the receiving unit. In this instance, challenging distances and environmental conditions must stop the receiving unit being able to distinguish between a 1 or a 0 to affect the quality of the output. Hence, with digital two way radio you get a perfect reconstruction of the voice and crystal clear communication OR you start to lose complete words or even the whole transmission when the signal is lost.

Advanced electronic design, efficient antenna's and high quality build criteria have ensured that the ranges achieved in the new 'digital-age' of two way radio are comparable or better than the analogue equipment they replace. Furthermore, the real benefit is in the great applications that have been developed for use with these digital units allowing simple connection to other digital products including Building Management Systems where an automated output can send texts to inform a facilities team that an air-conditioning units needs attention or the output from a fire-alarm panel can let personnel know about the existence of a fire and its location. It would seem that the writing is on the wall for the end of the analogue two-way radio, but the market will dictate the rate of change and nobody can predict that!