Our meeting presenters say its the way of the future...
A recent SARC meeting featured two guests, Doug Pattengale VE7CQT and Brad Wilson VA7BWX, who have been heavily involved in local Digital Mobile Radio (DMR). They have kindly agreed to share their presentation slides.DMR is a limited open digital mobile radio standard defined in the European Telecommunications Standards Institute (ETSI) Standard TS 102 361 and used in commercial products around the world. In the commercial world, DMR, along with P25 phase II and NXDN are the main competitor technologies in achieving 6.25 kHz equivalent bandwidth using the proprietary AMBE+2 vocoder. DMR and P25 II both use two-slot TDMA in a 12.5 kHz channel, while NXDN uses discrete 6.25 kHz channels using frequency division and TETRA uses a four-slot TDMA in a 25 kHz channel.
DMR was designed with three tiers. DMR tiers I and II (conventional) were first published in 2005, and DMR III (Trunked version) was published in 2012, with manufacturers producing products within a few years of each publication.
In our Amateur Radio world, DMS is one of three main digital radio technologies, with iCom D-Star and Yaesu System Fusion as earlier players.
The primary goal of the standard is to specify a digital system with low complexity, low cost and interoperability across brands, so radio communications purchasers are not locked into a proprietary solution. In practice, given the current limited scope of the DMR standard, many vendors have introduced proprietary features that make their product offerings non-interoperable with other brands.
To view or download the presentation, visit:
https://drive.google.com/file/d/1f9U1mXGQ6nOuE_umJCsPSIPiep-LLieD/view?usp=sharing
Our thanks to Doug and Brad for an informative evening.
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