DMR

Digital Mobile Radio (DMR) is an open standard for professional mobile radio. The DMR standard is defined by the European Telecommunicatons Standards Institute (ETSI) and may be used worldwide.

ETSI-TS102 361 Standard links:

DMR uses a channel spacing of 12.5 kHz. This is a common spacing for commercial analog radio communications. Using this spacing, DMR devices can work on frequencies previously allocated to analog systems. Modulation is 4 level FSK (4-FSK). There are two multi-channel methods for DMR: TDMA (Time Division Multiple Access) or FDMA (Frequency Division Multiple Access). TDMA is the most popular because it’s cheaper and easier to implement e.g. simpler duplexers/filters, etc.

A lot of brands already have DMR devices: Hytera (Best for Ham-radio usage), Motorola, Vertex/Yaesu, Tait, Selex, Simoco, Connect Systems, and more

DMR Advantages:

– Digital audio quality is better than analog audio quality except for perfect and worst case signal conditions, where analog and digital are nearly equal.

– 2 simultaneous voice channels (or data) on 1 frequency of 12.5 kHz channel allocation.

– Private-call/Group-call/All-call

– Digital features: GPS(LP)/ text messages(TM)/ Radio registration(RRS)/data services

– Connecting repeaters worldwide

Two DMR Networks:

- The Motorola network is the original network and works on the basis of Motorola repeaters in a certified, commercial infrastructure.

- The Ham-DMR network is based on Hytera repeaters and fully developed by radio amateurs infrastructure. The integration of other brand repeater hardware is planned.

DMR Registration:

There is only one registration system in the world. For Europe, it is the register.ham-digital.net page, accessible via www.ham-dmr.de under DMR-registration. For the rest of the world this system is also used in the US; both are coupled and use the same ID system and the same database.

Web systems (status pages, load Heard lists):

For web systems both networks (Hytera, Motorola) are connected. The Heard lists and DMR monitors partially display users of both networks.

Repeaters that operate on both the Hytera and Motorola networks, are in development. There are currently repeaters in Germany and Switzerland connecting DMR with D-Star.