TETRA Radio is Terrestrial Trunked Radio and as the name indicate they have the feature of trunking available for professional and recreational needs. Trunking means group chats are possible for teams handling emergency situations of friends gone for a mountain hike.
DMR is Digital Mobile radio was designed to replace analogue two radio system which offers pin to pin digital solution for two-way radio communication with less complexity and wider coverage range for Public safety professionals and amateurs to communicate in areas where other modes of communication might not be as effective.
Similarities between TETRA and DMR
Both Tetra Radio and DMR devices have similar functions like encryption, data transmission for GPS tracking, ability to send and receive textual messages privately and in groups, authentication, automatic handover, and roaming. Other shared features include direct mode communications; and private and conference calls. Despite these many similarities, these two devices are very different in numerous ways and practicalities.
If you are thinking about upgrading your radio mobile communication you should consider both of these and chose whichever meets your requirements best. Both handheld radio sets are digital technology designed to meet the needs of professions so what is the difference?
Differences between TETRA and DMR
Major differences are based on modulation and bandwidth leading to a difference in coverage capacities, the power to support traffic and the number of available channels. The modulation schema for TETRA is a linear four TDMA channels in a 25-kilohertz channel. The modulation schema for DMR is a robust fixed envelope that supplies the same RF power and sensitivity of conventional analogue systems. DMR employs two-slot TDMA with a 12.5kHz bandwidth while Tetra radio devices use 25kHz channels and four slot TDMA. This implies that DMR has a higher maximum RF power available tat is 5 watts in comparison to TETRA radio device which has only up to 2 watts.
What does it mean in simpler words?
To simplify, it means that Tetra portable terminals use twice the bandwidth, smaller cell size, and more slots. It has more features and better connectivity but is also more complex and costly while DMR is a simpler, cheaper option with accessories that can compete well with what tetra has to offer. DMR was developed for wider coverage with lower density, therefore, it uses the same radius of cells that were used in analogue radio devices it was intended to replace. Due to wider cells radius DMR is able to give better coverage area with fewer slots. Due to two slots in DMR, a more expensive branching system will be required to avail coverage for more number of channels.
Tetra radio devices with smaller sized cells require more slots for coverage are but can support more channels to transmit the traffic therefore high traffic volume. Tetra radio devices are less sensitive in comparison and have less coverage as they only work on UHF bands which impact propagation.
Why some professionals prefer DMR over TETRA?
For many consumers, the choice between DMR and TETRA feels like a Quality over Quantity dispute. It depends on your needs, would you rather have more features, more complexity, higher traffic, and high cost or simpler and easy to use design with less feature and lower overall cost.
Since the infrastructure of DMR is similar to analog system it requires minimum training for staff if you upgrade. You can use the same accessories like terminals and wires that were used for the analog system and a gradual shift is also possible. Maintenance and repair also cost less when compared to TETRA devices. Despite the high traffic volume availability, complexity and less coverage area sometime make Tetra devices a misfit for emergency situations public safety professionals have to deal with. In addition, TETRA has reduced spectral efficacy and causes more spectral pollution in comparison to DMR.
A base station for TETRA devices will consume more power than a base station for DMR devices. TETRA devices cost more due to the incorporation of all available features and fast and expensive dedicated switch nodes to facilitate trunking protocols. Due to added features, TETR does not only have an initial higher cost but also more expensive maintenance and additional expenses. DMR in comparison feels like a more cost-effective and simpler solution.