This blog post is intended to give an overview of the advantages and disadvantages of various types of two-way radio systems. These include short-term hire, licensed and licence-exempt systems (the so called “licence free”) in the VHF (Low / Mid / High) and UHF (1 / 2) bands.
LICENCE-FREE PMR446 WALKIE-TALKIE RADIO SYSTEM
Advantages
- They are easily available and can be used by most industries
- They do not require specialised tuning in order to use them
- Low cost
Disadvantages
- Their low power results in relatively short range compared with higher power radios
- Their easy availability may result in the channels being congested with multiple users
SHORT-TERM HIRE RADIO SYSTEM
Advantages
- No licence fee
- They are easily available via a specialised radio supplier, e.g. Wall to Wall
- They have more available frequencies than Simple UK radios
- They are less likely to suffer harmful interference than on Simple UK channels
- They typically operate a 8 x the power of a PMR446 walkie-talkie
Disadvantages
- In some areas, short-term hire channels may be shared with several other users
LICENSED SIMPLE UK RADIO SYSTEM
Advantages
- They are easily available via a specialised radio supplier
- Comparatively cheap licence fee when compared with other licensed systems
- May be used almost anywhere within the UK
Disadvantages
- Their sharing of a limited number of radio channels can result in the channels being congested with multiple local users
LICENSED SIMPLE SITE SYSTEM
Advantages
- A base station repeater may be installed – extending the range of the handheld radios
- Comparatively cheap licence fee when compared with other licensed systems
- May be used anywhere in the UK
Disadvantages
- The sharing of a limited number of radio channels can result in the channels being congested with multiple local users
LICENSED TECHNICALLY ASSIGNED BACK-TO-BACK SYSTEM
Advantages
- The channel is assigned by Ofcom using carefully planned sharing criteria. So, unlike the Simple Site / UK licences, any interference should be minimal
- Exclusive use channels are available in many parts of the UK
- The licence fee is greater than a Simple UK licence but, unlike the Simple UK / Site channels, Ofcom will investigate and resolve undue interference cases to this type of licensed channel
- The radios can be programmed in to groups of users with each group having an order of priority for channel access. For instance, the Emergency Group can be given the highest priority and, perhaps, Cleaners the lowest
Disadvantages
- Exclusive use channels can be very difficult to obtain in some dense urban areas, e.g. Central London. Ofcom’s licensing criteria, however, are designed to minimise undue interference between adjacent licensed systems
LICENSED TECHNICALLY ASSIGNED ON-SITE SYSTEM
Advantages
- The inclusion of a low-power base station and external antenna should increase the coverage radius of a radio system
- The base station antenna can be directional thereby concentrating the signals where they are required
- The inclusion of a down-fire antenna may increase the coverage down through multi-floor buildings and also reduce interference from adjacent co-channel users and
- Ofcom considers the use of a down-fire antenna to be spectrum efficient and rewards users with a low fee licence
Disadvantages
- Increasing the base station antenna height will increase the radio system coverage area but will also is increased the potential for incoming interference (see the above reference to down-fire antennas)
LICENSED TECHNICALLY ASSIGNED WIDE-AREA SYSTEM
Advantages
- A wide-area system may have a radius of 30km. This should result in users within, say, 20km of the base station being unlikely to suffer any interference from the base stations of adjacent systems, e.g. 40km away
Disadvantages
- Increasing the base station antenna height will increase the radio system coverage area but will also is increased the potential for incoming interference (see the above reference to down-fire antennas)
LICENSED TECHNICALLY ASSIGNED MULTI-SITE SYSTEM
Advantages
- Users at one site can communicate with users at all of the other connected sites
Disadvantages
- Communications between one or more sites could be disrupted if the large area network (LAN) connection is lost