Posted on Jul 31, 2019 by admin
As a specialist in radio systems we know a little about choosing the right radio system for your business. This article focuses in particular on digital radio systems from Hytera however we also offer excellent solutions from Kenwood, Motorola and even renewable energy powered systems.
There are two main choices for business within the Digital Mobile radio (DMR) standard, which operates in PMR frequency bands from 30–960 MHz: DMR Tier II conventional systems; and DMR Tier III trunking systems.
In order to consider which option is right for you you first need to consider the number of users and channels (talk groups) you wish the system to cater for. There will also be a communication ‘traffic’ implication from how often these groups need to talk. For example if cleaners come in once a day vs security teams who require comms round the clock. Data applications can also take up bandwidth which needs to be taken into account to avoid a system overload. As a general rule small to medium-sized enterprises with less than 100 individual users with the primary need for voice services only will find a DMR Tier II conventional system will suit their requirements.
DMR Tier III trunking systems are more typically used at airports and busy hospitals.These are ideal for more than 100 subscribers especially for access to advanced data application as well as voice services.
Tier II conventional radio systems use a dedicated channel for each group (or team) of users whereas Tier III trunking radio systems allocate a pool of channels automatically to different groups of users. The network in a Tier III system will assign the next available free channel to a speak from the pool of channels whereas the Tier II systems have a set number of channels which can talk simultaneously. Most systems allow 2 channels to talk at the same time however Zycomm regularly provide customers with a network of systems which allows additional groups to talk across a Tier II system. Hytera radio systems offer a number of ways to expand both capacity and coverage over a DMR Tier II conventional system: simulcast; and Extended Pseudo Trunking.
Expanding capacity in your DMR Tier II systems
If you have a DMR Tier II system in place and wish to increase capacity due to an expansion in your organisation or a change in team communication requirements then you can deploy Hytera Extended Pseudo Trunking (XPT).
XPT (an exclusive Hytera development) offers a way to replicate a distributed trunking network through a simpler, more cost-effective means compared with investing in a full Tier III trunking system. Those looking to double their radio capacity using their existing spectrum resource can do so through XPT without having to deploy a centralised system controller.
Simulcast or simultaneous broadcast system is another solution to extend coverage on a DMR Tier II system best suited to organisations looking for coverage over a wide area with limited radio frequency resources. Simulcast simultaneously transmits the same signal with very precise timings between base station repeaters by using two or more repeater sites on the same frequency. Just one frequency pair is required for the whole mobile radio system regardless of the number of base stations in the network.
Considerations regarding Frequency
The spectrum you chose whether VHF or UHF (both available on DMR radios) will depend largly on the nature of your business. VHF is ideal for outdoor use particularly over long distances such as a construction site particularly where the terrain is not too hilly, built-up or with woodland.
UHF works well for indoor use and built-up urban areas as it is a more effective means of penetrating concrete and metal. It may also be a better solution for woodland and hilly areas outdoors. Some companies prefer UHF for the relatively short antennas which make the device more discrete and portable.
Licencing frequencies need to be considered to ensure you don’t have interference from nearby businesses with neighbouring digital radio systems, this is of particularly concern in large cities such as London. In the UK, licensed frequencies are available for DMR systems in UHF (400 – 470MHz) and VHF (136 – 174MHz) channels. Regulator Ofcom provides several grades of licence (an obligatory requirement for professional radio users) to suit different levels of requirement.
Simple UK Light is suitable over a small coverage area where a base station is not required. 15 frequencies spread across four business radio bands are available.
Simple Site Light covers the operation of a base station along with radios used over a small area (typically up to 1km) which is often a good solution for warehouses and modest industrial units. These need to self-coordinate with other Simple Site Light licensees.
A Suppliers Light license is for business radio suppliers who service, repair and hire out business radios such as Zycomm Electronics.
An Area Defined license provides you with the exclusive use a frequency which could cover the whole of the UK, a county or a large defined area. However in practice in the UK the availability of UK-wide channels above 165 MHz is extremely limited.
Here at Zycomm Electronics we can happily advise companies on the licence which will best suit them along with technical engineers who can guide you through the digital system process whether you are looking at migrating from an old analogue system, looking at expanding capacity or want to discuss any element of your communication requirements. Speak to our team today
The article above first appeared in a similar format on the Hytera UK website. Zycomm thanks Hytera for allowing us to share this article.
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