Digital Mobile Radio or DMR for short is where most of the digital voice activity is taking place in amateur radio today followed closely by Yaesu's C4FM based System Fusion.
On the rise, but still far away in terms of users and repeaters is NXDN. Just like DMR, NXDN is an open standard and was jointly developed by Icom and Kenwood, who in the amateur radio world only have the well aged D-Star mode on offer to cater to digital voice amateur enthusiasts.
Yaesu Fusion is not an open standard although it shares some similar attributes with NXDN because of underlying technology. Alinco is the only current non-Chinese original vendor to offer an amateur grade DMR radio.
The History of NXDN
After 3 years of development, the NXDN standard was finalized in 2005 and product aimed towards commercial users appeared one year later.
NXDN is based around frequency division, multiple access technology which allows different communication streams to run concurrently with only minor frequency separation. While Yaesu Fusion is also FDMA based, it is not compatible with NXDN or dPMR, which is starting to become popular as PMR or FRS unlicensed analog radio replacements in certain parts of the world.
DMR which is TDMA or time division multiple access based interweaves two different communication streams together in one 12.5 kHz wide channel.
NXDN can make used of its FDMA technology to run in either a signal communication stream mode in a channel that is 6.25 kHz wide or marry two streams together and still work in one 12.5 kHz stream. DMR can only work in one 12.5 kHz channel and offers no narrow band option.
Both NXDN and DMR can support voice/voice, data/data or voice/data essentially at the same time in the same 12.5 kHz channel which is very efficient. DMR is the only mode in use today in amateur radio that is actively capable to support this "two discussions, on the same frequency, at the same time" functionality though.
As of the time of this article, the only way for amateur radio operators to use NXDN is through commercial new or surplus equipment. There is not one single amateur grade or market NXDN radio available. It is possible for users of Yaesu Fusion and DMR to talk to NXDN users by way of mode translation offered my MMDVM hotspots, but this is not the same as native speaking NXDN to NXDN radio.
In past HVDN articles, we have covered the rise of DMR by looking at the number of repeaters deployed globally. When it comes to NXDN, we will track registered users and also repeaters moving forward starting with this article.
United States: NXDN Amateur Adoption
DMR started life as a commercial communications solution but in a few short years started to see second life in amateur radio. NXDN may be the eventual front runner for digital amateur communication for a few reasons. Lets first look at the current state of NXDN adoption in the United States which holds much of the global activity so far.
As of the May 2019, there are only 1,963 global registered users ID's for NXDN and 61.6% of them are in the United States.
Of the 61 represented countries in the radioid.net database, 6 other countries capture 20.3% of the remaining NXDN ID's which leaves 54 countries around the world to account for the remaining 18% of users not yet accounted for.
The total number of NXDN user IDs grouped by major geographic regions indicate that the south eastern part of the country is the hotbed for NXDN users with Florida and Arkansas holding the two largest pools of users as of the time of this article.
Another view through the lens of FCC amateur radio regions illustrates that regions 1, 4, and 5 are far ahead of the rest of the country. With a total of 20 states represented out of 51 (Including D.C), there is much room to grow in other areas.
NXDN United States Amateur Repeaters
Over the last few years, HVDN has used repeaterbook.com to keep track of digital voice repeater data with our latest tracker being issued just before Hamvention 2019.
In the data captured on May 9th 2019, there were 119 NXDN repeaters globally. With Hamvention over, there is already one additional NXDN repeater according to the same data source bringing the total to 120.
NXDN: Future Outlook
With only commercial equipment for both radios and repeaters being available to amateur radio operators, should a vendor such as Icom or Kenwood introduce the next generation of digital voice radio based around NXDN, they may possibly create a similar growth trajectory that DMR has experienced in recent years.
This may put Yaesu in a tough position to maintain control over its single vendor C4FM/FDMA/YSF/Fusion ecosystem unless it opens up its standard to all other vendors to promote inter-operable digital voice radios across vendors.
Chinese vendors like Ailunce, TYT, Radioddity and Retevis may also be challenged to compete, but may eventually offer lower cost NXDN equipment. Alinco does currently offer NXDN capable radio such as the DJ-NX40, but is aimed at commercial users.
Further reading:
NXDN: Future Outlook
With only commercial equipment for both radios and repeaters being available to amateur radio operators, should a vendor such as Icom or Kenwood introduce the next generation of digital voice radio based around NXDN, they may possibly create a similar growth trajectory that DMR has experienced in recent years.
This may put Yaesu in a tough position to maintain control over its single vendor C4FM/FDMA/YSF/Fusion ecosystem unless it opens up its standard to all other vendors to promote inter-operable digital voice radios across vendors.
Chinese vendors like Ailunce, TYT, Radioddity and Retevis may also be challenged to compete, but may eventually offer lower cost NXDN equipment. Alinco does currently offer NXDN capable radio such as the DJ-NX40, but is aimed at commercial users.
Further reading:
Conflating DMR (which generally applies to DMR Tier III, Hytery XPT, and the MotoTRBO variants) with amateur digital modes will only increase the confusion.
ReplyDeleteNXDN is a variant of NEXEDGE, as is IDAS, which is also a commercial protocol.
Oops, I mean Hytera XPT.
DeleteDave - What are you even getting at? DMR (as defined as the ETSI standard pertaining to tier 1, 2 and 3) is used as a general family term. Same goes with NXDN which is another open standard. Various vendors call them different things as you point out which I agree on.
ReplyDeleteIts pretty understood in every amateur conversation what is being talked about when referring to DMR and NXDN. Perhaps the only rotten apple that created issues were those horrible Baofeng DM-5R radios, but many quickly learned to avoid them.
Feel free to join the Brandmeister TG 31630 net that meets on Tuesday evenings at 9:00 PM NY time to share a thought or two.
Thanks for posting tthis
ReplyDelete