D-STAR Early reaction – 51A/E Plus2 Special Color Edition

Editor’s note, February 2018.   My original note was written before the 51 Plus2 had begun to ship.  By reading the user manual for the AccessPoint/Terminal mode software (RS-MS3A or RS-MS3W), we learned these new modes utilize ICOM Callsign Routing only — no linking to reflectors. 

At Dayton, 2017, I learned ICOM and Robin AA4RC were discussing adding linking to REF reflectors, but that never happened. Though I am not a fan of Callsign Routing, I have to say that the Plus2 and 4100 are really excellent D-Star radios.  They are worth the money, even if you don’t use the new modes.  But the new modes can be fun, as long as you understand how Callsign Routing works.  And to be honest, I have not given up hope that 3rd party developers will find a way to leverage these radios for linking to reflectors.  But that is for another day. 

Bottom line — don’t get a 51 Plus2 or a 4100 if you want to use AccessPoint mode or Terminal mode to connect to reflectors — they only do Callsign Routing.  Otherwise, they are great D-Star radios.  And you might learn something about Callsign Routing in the process….

But the following stands as it was originally written, except for some new notes with added info. 

A lot of D-STAR fans are looking at the 51A/E Plus2 announcement – in particular Terminal Mode and Access Point mode.  Many of us have done DIY projects to create Hotspots with modems and analog radios to extend the D-Star network to our area, or have bought DVAPs, DVMEGAs and DV4minis to do the same thing with lower power.  The Plus2 Special Color Edition promises this functionality as part of the radio.

The D-STAR Round Table on XRF002A, a very popular D-STAR net on Thursday evenings 11pm Eastern, 8pm Pacific, had an interesting discussion/conjecture session recently about the new radio.  Keep in mind there is very little published info about this product yet, so conclusions will change as we learn more.

Reflector Types
Originally, DPlus linking to REF reflectors was entirely a non-ICOM, third party effort (by Robin Cutshaw AA4RC).  Eventually, ICOM understood the business value of this effort and created DR Mode, which basically incorporates DPlus commands into ICOM D-Star radios.  In the meantime, other developers have added increased functionality and created two other linking systems.  ICOM, however, has so far done nothing to support linking to DExtra (XRF) and DCS reflectors.

If you get a DV Dongle, DV3K or DVAP from Robin and Moe’s company, they recommend you use Robin’s software with those products, for example, DVTool for Dongles, and DVAPTool for DVAPs.  If you do use those, you will be able to link only to REF reflectors or ICOM repeaters running DPlus, via DPlus only.  That is one reason so many people now have moved to G4KLX software for their Dongles and DVAPs, since it also supports XRF and DCS reflectors, as well as CCS7.

So the educated guess is the Plus2 will continue to focus on REF linking, with no support for XRF and DCS linking.  This could limit its popularity, given the relative increase — world wide — in the use of XRF and DCS reflectors, compared to REF reflectors.

Terminal and Access Point Modes
One comment came from someone who has used the Android app from ICOM called RS-MS1A (catchy name).  This connects to certain ICOM D-Star radios via a special cable OPC-2350LU, and enhances the operating experience and allows controlling from the Android device.  It supports DR Mode (REF linking only).   Note: It will also work with BlueTooth (e.g. on a 5100 with BT), but I am not aware how to get BT on a 51A.

During the Round Table, there was conjecture the new Plus2 features will derive from an enhanced version of the RS-MS1A app, adding the Terminal and Access Point Mode functionality to the Android app.  Note that the $70 cable is free with the new Special Color Edition of the 51 Plus2.

Internet Access Questions
The brochure mentions needing “a public IP address” which raises the question whether devices behind a NAT router will work.  Whether using WiFi at home, at a hotel or coffee shop, the WiFi provider usually assigns a private IP address (192.168…, 10.10….).  More info is needed about this issue. (Editor’s note:  The new modes work fine behind a router; you just have to port forward UDP 40000 to the computer running the RS-MS3 software.)


  • Duty Cycle – If linked to a busy reflector, the 51 Plus2 could find itself running at nearly 100% duty cycle. This could lead to overheating.  The solution is to reduce output power to a low level, which will affect the range.  On the other hand, DVAPs, DVMEGAs and DV4minis all run about 10 milliwatts and give good coverage in the average home, and often out to the backyards and gardens.
  • Battery Life – This could be a show-stopper, given the Duty Cycle issue. The 51’s battery has a reputation for losing its charge quickly with active use. So far, there has not been a 3rd party battery eliminator product created for the 51.  Batteries America makes the CBE-217 battery eliminator for the 80AD and 91AD D-Star radios, but they have not created one for the 51A.  So this creates a limitation for Access Point mode that could cripple its use.
  • No iOS/iPhone/iPad version – This will limit usefulness, given the size of the iPhone/iPad market.
  • Tethered by cable to Android device – Bluetooth connection not supported.  See details above.
  • No Open Source announcement – ICOM’s software so far has all been closed source.  The concern is this new app could quickly be left behind in the current dynamic development environment.  If ICOM cannot keep the software up to date with the rapid changes in Digital Voice networking, the product could find itself obsolete for a wide range of D-Star users.

Conclusions based on what we know so far
These new capabilities will be useful to people who are not ready or don’t have the time to get some of the 3rd party products and set them up.  That is good for them and for the growth of D-Star.

Others will run into the limitations on linking, need to use a cable to connect the 51 to the mobile device,  duty cycle and battery and will be motivated to move on to some of the 3rd party products, maybe run the software on a Pi using DStar Commander, Maryland or WesternDStar images, and get even more functionality.

Thanks to Bob W6DK, John K6KD and others for providing the info and comments used in this post.

Banner artwork by Philip "GilGildersleeve, W1CJD.   His cartoons adorned QST for many years.   I encourage you to get "GIL Cartoon Collection Download".