D-STAR Terminal Mode

A new How-To Guide for D-STAR Terminal Mode

Quick Links for Reflector Linking (REF, XRF etc.)
* Radios using OPC-2350LU data cable  (51 Plus2, 3100 Plus, 4100, 5100)
* Radios using  USB cable (705, 9700)

When Icom first announced their new Terminal Mode feature in selected new D-STAR radios, fans of D-STAR got curious.  They discovered these new radios could transmit over the internet to D-STAR repeaters, giving people who were out of RF range from a repeater a chance to have fun.

A computer with internet connection is needed, and ICOM made their software available for download.  But people discovered they could not link to reflectors and wished there were another alternative.  G4KLX, author of a popular Open Source suite of D-STAR and digital voice programs, came to the rescue by adding a feature to his DStarRepeater program.   Two years later, PY7LIM, author of BlueDV and Peanut, write Doozie that works with all Terminal Mode-capable radios.  The end result is an easy way for Terminal Mode radios to link to all available reflectors without an expensive Hotspot.

But people had trouble learning about how to do this, and as Admin for the W6CX D-STAR Gateway in Northern California, I got many questions about Terminal Mode.  So I decided to write this guide:

D-STAR Terminal Mode Hotspots Made Easy

There is an overview, plus detailed How-To pages that will allow you to get a Terminal Mode Hotspot up and running quickly.  Enjoy!

Zastone Mini9+ DMR HT

Larry WW6USA pointed me to a very small DMR HT made by Zastone.  It was endorsed by Don WB5EKU who found it’s a great backup DMR radio to access a hotspot* around the shack or property.

This little HT’s main selling points are its small size and sturdy construction, but I have to say I am also impressed by the LED display that’s hidden behind the plastic case.   The radio has two important features that are missing, but for me, the small size and neat design more than offset what’s lacking.  On eBay, the prices seem to range from US $53 to $60.

The radio is a mere 90mm x 61mm x 30mm (3.4″ x 2.4″ x 1.2″) in size and weighs only 135g (4.8oz) without the removable antenna.  The small size and light weight are the reasons I got this radio.  I can slip it in my pocket, use the included belt-clip or if I were the type, I could wear it around my wrist using the included lanyard (I’m not).  Its 2 watts at high power more than covers my property inside and outside and it has no problem picking up my 10 milliwatt hotspot. So while I do have a large and more robust DMR HT, I am finding I prefer to use this little one around the house.

Now, the drawbacks — by far the biggest issue is that it listens and transmits on both timeslots at the same time.  This means it will not work with a DMR repeater nor with a duplex hotspot that is configured to use both timeslots.  This clearly was a design decision to reduce manufacturing cost.  But I deliberately use simplex hotspots which, on DMR, use only one timeslot.  So this “feature” of the Mini9+ is no problem for me.

The other drawback is that the screen displays the channel number and cannot display a channel name.   At home, I usually use just a few channels set up for my favorite talkgroups, so this is not a problem, and I have printed a list showing all channels and their talkgroups.

In keeping with the small size, you can set up a maximum of 128 channels and only 64 contacts.  Yes, on larger HTs I like to load Contacts with all the ids and callsigns in the world so I can see the ham’s callsign on the screen, but that is not needed with this HT.  I have not found the small memories a problem, given the way I use this radio.

Bottom line — these deficiencies don’t stop me from enjoying the radio and I do love its small size.

As my 7th grade English teacher used to say, “it’s cuter than a bug’s ear.”

Jim – K6JM

PS To program this HT, you can use any of several programming cables.  I found the cable that works with my old BeoFeng UV-5R analog HT also works with this radio, but a new cable costs about US $9.  Just search eBay for”USB Programming Cable For Zastone Mini9″.

PPS While the free programming software from Zastone’s site is similar to all other DMR radio programs, I must admit that I normally do not specify an RX Group list.  Yes, I know, some people like to monitor various talkgroups at the same time, and some setups will transmit error messages on a special talkgroup.  But I generally don’t fill in the RX Group list field.  That won’t work on this radio.  You will probably set up a list with all the TGs your channels refer to, or I suppose you could set up a different list for each channel with just the one TG.  But this radio will not let you hear a TG unless it is in the RX Group list for that channel.

*These days, so many people who want a digital voice hotspot use some form of multi-mode hotspot.  I am partial to those inspired by Jonathan G4KLX and designed by Jim KI6ZUM.  I have two right now — One is a ZUMspot with a 10 milliwatt RF chip on it.  The other is an MMDVM modem that drives my old Kenwood D700 set to output about 5 watts on UHF.  But that is another story….

Homebrew D-Star HF Today

I recently tuned into the wonderful Thursday Night D-Star/DV Round Table net on XRF002A (7pm Pacific) and heard a question — he has an ICOM IC-7000 transceiver and he’d like to adapt it to be able to have D-Star QSOs on HF.

Before answering that question, of course the simplest (if not the cheapest) answer is to get an ICOM HF radio that supports D-Star, for example the IC-7100 or IC-9100.  But, that was not the question, and the IC-7000 is a terrific radio.

Digital Voice advocates, particularly those using D-Star, solved this problem in the early days of amateur radio DV, but with all the focus on internet-connected hotspots and multi-mode, I’m not sure it is still easy to find the hardware that will work with existing software.

Old Solutions That Should Work Today

Solution 1 is the more interesting, but has a “gotcha”, in that you will need to find or build the “simple interface”.  Solution 2, assuming the GMSKClient software works with a DVMEGA GMSK modem,  is similar to the first one, but easier.  Therefore (with the above disclaimer), I recommend Solution 2 for most people.

Solution 1 – Soundcard approach
Use the G4KLX program SoundCardClient with a simple soundcard dongle.

This approach is pretty simple.  The pc program passes the mike’s analog audio to the AMBE device, which converts it to a compressed digital bitstream, which is then modulated to audio tones by the 2nd soundcard and sent to the transmitter.  On receive, the audio tones need to be demodulated back to a digital bitstream, sent to the AMBE device for decompression to analog audio and sent to the pc’s speaker via its 1st soundcard.

What’s needed:

  • G4KLX’s SoundCardClient software (available in the Digital Voice package on the “dstar_development” Yahoo Group’s Files/Beta folder). This program will run on a computer (no internet needed) with pc mike and speakers.
  • A  low-end USB soundcard dongle – it’s important there be no filtering in the audio chain, and the better soundcard dongles often add filtering.  Get the cheapest dongle you can find.  You can search for details on the dstar_development Yahoo Group.
  • An AMBE device, like the original blue DV Dongle or a NWDR ThumbDV.
  • A transceiver providing access to the modulator on TX and the discriminator on RX with audio paths unfiltered — typically a radio supporting 9600 baud Packet data will do the trick.
  • An interface that will provide TX and RX audio along with a PTT line.  This is the one thing you’ll have to build or find yourself.

Looking at the manual, the IC-7000 does support 9600 packet and has the traditional data socket (6-pin mini DIN) on the back.   Caution:  I don’t have this radio and have not tested it in this mode, but chances are very high that when packet data rate is set to 9600, the radio will not introduce audio filtering and it should be able to do D-Star.

The interface is the most interesting part of this project.  What we are doing here is quite similar to people doing classic digital modes like PSK-31.  So you can search for digital mode interface products (my search term was “ham digital mode interface”.   They all just want to route RX and TX audio to the appropriate pins on the radio’s digital data connector.  Some have a built-in soundcard.  Some have built in VOX to key TX, or they use the radio’s vox.  BUT — there are two problems with many of these interfaces:  1)A built-in soundcard may have audio filtering that will work for classic digital modes, but will filter out the low audio frequencies used by D-Star’s GMSK modulation; 2)VOX PTT keying may cause a delay such that the radio will fail to transmit the very beginning of the D-Star transmission, which is when then routing headers are transmitted.

Back in the day, I used a spare BuxComm Rascal interface.  This does not do VOX PTT.  Instead, it has a PTT circuit keyed by  the pc’s serial port (these days, one would use a USB to serial cable to the interface).  The Rascal had a filter capacitor in the audio path that I had to bypass, but then it worked well on D-Star.  Today, one would search the internet for something similar.  When I get time, I will do that myself and update this article.

I suspect the UDRC-II (Universal Digital Radio Controller) from Northwest Digital Radio would also do the interface job, but I have not tried it for this function.  I notice they are currently out of stock, but NWDR produces great products, so I would consider this if they get it back in stock.

Solution 2 – GMSK modem approach

OK, I “think” the software will support the DVMEGA GMSK modem, but I have not tried it.  So before proceeding, get assurance from someone who’s tried this that it works.

Similar to the soundcard solution, but easier.  While most GMSK modems are no longer available, DVMega has a good one that pairs with an Arduino Uno controller.  This approach has the advantage of being designed for GMSK modulation and allows the computer to control PTT.

Other solutions, no longer available

  • DVRPTR modem hardware, G4KLX DVRPTRClient software. If you have an old DVRPTR modem, just get the software from the dstar_development Yahoo Group, same place where you can find SoundCardClient.  The interface is part of the solution; you just need a 6-pin mini DIN cable.
  • Star*DV AMBE device, Star*Board GMSK modem and SDV software.  This was a terrific solution from Matrix Circuits.  Their engineer, Rick KD0OSS, designed the AMBE device and wrote the SDV software.   While originally designed to work with the ircDDBGateway for linking to reflectors, you can just not run ircDDBGateway and use the modem to drive your analog radio.  SDV features the ability to change TX Invert settings when changing bands.  It was a great D-Star HF solution!

There could easily be better, simpler solutions out there that I am not aware of, or have forgotten.  If so, please let me know!

MultiMode Presentation at Pacificon 2017

Jim, KI6ZUM was featured at the MultiMode Digital Voice presentation on October 2, 2017 at Pacificon in San Ramon, CA.  Jim K6JM and Don WB5EKU were also part of the presentation.  

The presentation was video-recorded and is being edited.  A link to the video will be shown here and on various other websites as soon as it becomes available.

In the meantime, you can take a look at the slides here:

MultiMode Digital Voice – Pacificon – Oct 21 2017 – Jim KI6ZUM, Jim K6JM, Don WB5EKU

Multi-Mode DVMEGA Access Point


A year ago, I got interested in getting a DVMEGA-based multi-mode access point that I could use either at home or on the road, but until recently, the project had not gotten done.

Note: This article only covers using the access point with a D-Star radio. But it also works well with DMR (Brandmeister and DMR+) and C4FM/Fusion.

This access point is based on the DVMEGA Raspberry Pi Dualband Radio board, but instead of plugging it into a Pi and running Digital Voice programs there, you instead plug it into a Combitronics BlueStack-Micro-plus board.  This little board provides BlueTooth communications with an appropriate computer running BlueDV software.  In other words, the Pi is replaced by a BlueTooth board and a pc, smartphone or tablet.  The result takes up very little space and consumes little power.  It makes a small footprint in the shack, and is also perfect when travelling.

So at Dayton 2017, while talking to Guus van Dooren PE1PLM, the founder of DVMEGA, as well as Ruud Kerstens PE1MSZ founder of Combitronics (maker of BlueStack) and David Grootendorst PA7LIM, author of BlueDV, I decided to go for it.  The DVMEGA booth was part of the large Gigaparts area, so I walked over a few feet and bought the DVMEGA board from Gigaparts,  the BlueStack board, a small antenna (see footnote) and, for fun, a cute little clear plexiglas enclosure.


Note: I already had a DVMEGA Dualband Arduino shield, and had used DVMEGA D-Star firmware with success.  But this was to be a multi-mode project, allowing me access not only to D-Star XRF, REF and DCS reflectors, but also DMR networks (BrandMeister and DMRPlus) and C4FM/Fusion networks, dynamically switching modes based on which mode radio I used.

Returning home, I discovered the latest multi-mode firmware was already loaded onto the DVMEGA board (no Arduino needed for this version of the board), though, if needed, it would have been easy to download and install.

I plugged it all together (to say I assembled it sounds like more work than it was) and paired the BlueStack board to my Android (older phone, Samsung Galaxy S3).  I downloaded/installed the BlueDV application on the phone and it immediately showed it was BT-connected to the BlueStack/DVMEGA boards.

The BlueDV application is wonderful.  David has kept it simple to use, but provided plenty of functionality.  I did the minimum setup (callsign, frequency, etc.) and did my standard first test — I linked to the E-module of an REF reflector and transmitted to it.  It recorded my transmission and played it back to me.  In other words, the access point worked the first time.


I have used it in D-Star mode a number of times since then. Recently, I was out of town during the well-known D-Star Roundtable on XRF002A on Thursday evening 7pm Pacific.  My cell had a decent signal at the motel, so I started BlueDV, turned on the access point and I was able to participate in the net using my 51A D-Star HT.

Further information:  I generally first visit the DVMEGA site to learn more, though the UK distributor also has good information.  For ordering, see the footnote below.

Power sources:  The BlueStack board, which also powers the DVMEGA radio board, is powered by the ubiquitous microUSB connector, so any Pi-type supply will work.  On the road, I use the PowerAdd Pilot 2GS 10,000 mAH supply.  I don’t know how long the access point will run from this supply, but I have run it all day and used less than 50% of the battery.


* Note on antennas:  Gigaparts sells the Maldol MH-209SMA, which works fine, but is a bit tall.  I ended up getting a smaller multi-band antenna, modeled after the Diamond SRH-805S.

** Note about ordering DVMEGA and BlueStack products:  In the US, your best bet is to order from Gigaparts, who is DVMEGA’s distributor there.  In the UK, order from DV-MEGA DStar.  From everywhere else, first visit the DVMEGA home site. When you order, you’ll be taken to the Combitronics site, the official DVMEGA distributor outside of the US and the UK.  Actually, anyone can order there, but shipping costs could be an issue.

DARA and its Project Management Victory

hamvention2017cDayton Hamvention 2017 — I believe the Dayton Amateur Radio Association pulled off an incredible feat of project management and it was a wild success.  They had only 9 months to lock in a new site, work out all the logistical details and manage 650 volunteers.  It basically went off without a hitch.

OK, the first morning, there were some traffic problems.  At the old Hara arena, it took me 10-15 minutes after parking to be at the Hamvention site.  The first day at the new site, it took me 35 minutes.  I kind of think the extra 20 minutes I experienced were not a big deal.  I had, after all, allocated the entire day to the Hamvention experience.

The Forums, as usual, were varied, fun and full of good information.  When sitting in a Forum session, it felt the same as the previous 13 Dayton Hamventions I have attended.  But step outside, things were a lot better than before.

In my opinion, the food was better than anything at the previous site.  I think there were more people attending, but there was more space in the aisles and I felt less crowded.  There was a central meeting area that felt like I was attending a local county fair.  Moods were good all around.

There were a few thunderstorms – it always rains a bit at the Hamvention, but I happened to be inside every time so that was not a big deal for me.  I would say I had to do more walking, not a lot more, but it was a bit harder to get to the Flea Market.  The biggest complaints about the new site will probably come from the Flea Market vendors.  They were on grass, not asphalt as before, so the rains produced some mud and probably limited customers after the short rains.

Everywhere, there was the spirit of trying to make things as good as possible for the customers, while, at the same time, thinking how to improve things for tomorrow and next year.  As an example, besides parking at the site, DARA and and the town of Xenia provided four other off-site locations for parking, with (free) school buses shuttling back and forth all day.  I chose to park at the Greene County Service/Engineering Complex. That first morning, the supervisor of the bus drivers was greeting all us attendees, making us feel at home in Xenia, but she was also monitoring and recording every bus trip, the timing, everything.  She said they wanted data to be able to improve things.   And they did, the very next day.  Most of the Friday issues were improved by Saturday.  That kind of attitude — teamwork, gather facts, analyse, fix — was evident throughout the 2017 Hamvention.

Hats off to DARA, to General Chairman Ron Cramer, KD8ENJ, and to Assistant General Chairman, Jack Gerbs, WB8SCT, and all the volunteers for making this a successful and enjoyable Hamvention!

Dayton 2017 – D-STAR and Digital Voice

hamvention2017b hamvention2017a

There was a lot of D-Star activity at Dayton this year and much of it involved support for multiple modes. The key third-party players who attended were Robin AA4RC of Internet Labs; Uli, Torsten and others from the DV4 Team; and Guus and his DVMEGA Team.

Jonathan G4KLX, Bruce VE2GZI and Jim KI6ZUM were unable to attend, so while their incredible work over the last year was not officially talked about except by Guus of DVMEGA, it was obvious their work has been influencing other developers.

One piece of news I learned that was not officially announced was that ICOM is in talks with Robin to add DPlus linking to the 51A Plus2/4100 new features. I heard it directly from Robin. As of the Hamvention, they had not signed the deal, but it sounded like both ICOM and Robin intend to do it and they are just working out the terms. I asked Robin if I could share this info, and he said yes. The next day, I talked to another ICOM employee and asked him about this. He confirmed there were talks underway.

I do not know how Robin will accomplish this, and if other third party software will be able to leverage the technique to extend linking to other protocols like DExtra and DCS. Of course, if only DPlus were supported, XLX reflectors that can be accessed both by Dextra and DPlus protocols would allow some partial relief.

A video of the D-STAR Forum moderated by Robin is found here. Robin’s talk starts at 41:30.  This video has excellent audio, but the slides are hard to see.  My phone video is not as good, but has a better view of the slides here.

Other news:

  • Robin announced DPlus 3.0 with “Fast Sync” to come out in the next week. The big change is DPlus Reflector code will no longer have to periodically sync all terminals from the Trust server, which will greatly speed things up. DPlus will still get a list of basic callsigns (not terminals) for purposes of authentication, but it sounded like it will not use the sync process to get that list, and of course that is much smaller.
  • Robin was asked if DPlus 3.0 would support XRF and DCS linking. He said his own code would not, but that with the new Fast Sync approach, it might be possible for other systems to be supported. This was really vague and I am inclined to wait and see on this.
  • Robin announced a new family of products called DV Air. These new products address the issue of Hams who don’t want to tinker with a Raspberry Pi, load images, configure, etc. I gather each of these products will contain a pre-programmed and mostly configured computer in a really, really small enclosure. Robin emphasized the key feature is “It just works”. See info from his slides below.
  • John K7VE of Northwest Digital announced they are working on a 1WattSpot — a small board with a 1 watt RF chip on it. This gets around the 7021 problems and with more power. They have more work to do to get D-Star to work (so they are not promising D-Star support yet, though you can tell they plan to get it to work), but they know it will work for several other modes. I think the RF chip has some low audio frequency filtering that they will need the manufacturer to remove to reduce BER on D-Star. Target would be those wanting a mobile Hotspot with more power than 10 milliwatts but not needing a high powered Hotspot. It appears they plan to price this reasonably.
  • Guus van Dooren of DVMEGA had a booth within the Gigaparts area. Ruud PE1MSZ of Combitronics/Bluestack was there, as well as David PA7LIM. Guus referred to them all as the DVMEGA Team, though they operate independently. They announced (at their booth and at the D-Star meeting Friday night at the Drury Inn) a new family of multi mode products called myDV: myDV Dongle, myDV Cast and myDV Handy. See details below. The myDV Cast seems to be an “internet radio” in a (very nice 3-D-printed) box. Inside is a Pi, Nextion LCD, AMBE chip, etc. but no RF. It appears this targets the same market as DV4Home, but pricing will be closer to US $300, not $500. (Personal comment: I noticed the existing DVMEGA products were selling really well at the Gigaparts booth. I think people like that they work, are well-engineered and priced reasonably. But clearly, all multi mode stuff is where the excitement is right now.)
  • Uli of the DV4 Team talked about a new feature of Control Center that will support dynamic creation of a private “room” into which up to 6 people with DV4Minis can connect. Each user can connect using any of their supported modes (DMR, Fusion, D-Star, P25 etc.) and the room will dynamically do the cross mode transcoding. Apparently this feature was accidentally released in an image last week, so this was not a total secret. While this kind of dynamic interoperability across modes is interesting, obviously the restriction that all users must be using DV4minis is significant.
    • Uli also said they will be shipping the long awaited DV4Home2 by June for US $499. It supports DMR+, BrandMeister, as well as DMR-Marc via their IPSec-based software into a C-Bridge. There are two AMBE 3000 chips in the box, allowing transcoding. Uli told me the hold-up for D-Star to DMR transcoding is more licensing, but it sounds like they plan to try to make that happen.
    • Uli announced the DV4Mobile (based on the same board as the DV4Home, but with RF capability) is still being worked on, but will be available later this year. They made 200 boards for Beta testers and once all is working, will sell those for US $800. Production boards, when available, will sell for US $1,200. It will be interesting to see how many of those will be sold.


Internet Labs’ DV Air family – plug and play devices with CPU and embedded OS that support DV Dongle/DV3K and DVAP, with a battery inside, eliminating the need for a Pi or equivalent, a battery and especially configuration.  Here are the words from Robin’s slides about these new products:

DV Air 3K
• AMBE 3K (builtin)
• Wireless Bluetooth
• Wireless Wifi
• Wired Ethernet
• Internal Battery
• iPhone/Android
• Windows/Mac/Linux
• Instant ON
• No SDCARD images
• No glitches

DV Air (no AMBE chip, but added USB Host port)
• Plug & Play with DV Dongle and DV AP
• Wireless Bluetooth
• Wireless Wifi
• Wired Ethernet
• Internal Battery
• iPhone/Android
• Windows/Mac/Linux

DV Air Pro (with AMBE chip and USB Host port)
• Plug & Play with DV AP
• Wireless Bluetooth
• Wireless Wifi
• Wired Ethernet
• Internal Battery
• iPhone/Android
• Windows/Mac?linux
• FM radio? (since DV AP can do analog FM, working on doing D-Star from analog FM radio)

Next – DV Air AP (future product)
• Multimode RF (not 7021, working with new RF chip)
• Wireless Bluetooth
• Wireless Wifi
• Wired Ethernet
• Internal Battery
• iPhone/Android
• Windows/Mac/Linux


DVMEGA myDV family

myDV Cast
• Multimode Direct Voice Device
• Direction Connection to Talkgroup or Reflector
• Support for D-Star and DMR. Fusion to be done.
• BrandMeister, DCS, XRF, REF, XLX, YSF, FCS and DMRplus

(Don’t have details about myDV Dongle and myDV Handy, but clearly the Handy refers to a D-Star radio.)

— Jim Moen – K6JM

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 announcment – 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 - A Collection of Classic Cartoons from QST". 

Hotspots vs Access Points?

Hams into D-Star and other digital voice modes sometimes ask themselves whether to set up a Hotspot or an Access Point.  Sometimes they just want to link to their favorite reflector without bothering others using the local repeater.  Or, there is no nearby repeater, but they want to get on D-Star.  Or they will be travelling and want to bring D-Star with them.  Both Hotspots and Access Points can, as I like to say, extend the D-Star network (and increasingly, other DV networks) to your QTH, neighborhood or region. Both require a D-Star radio, typically an HT. So radio is involved, at least in the last mile or last foot, with every QSO.

There is no arbiter of terms in this niche of our hobby, but “traditionally,” a Hotspot has consisted of an internet-connected PC with appropriate software, a modem of some sort, and an analog FM transceiver. These are often capable of between 5 and 40 watts, though rarely do people run at the maximum power level. These Hotspots, particularly with a good outside antenna, can provide coverage from a few miles to quite a bit farther. And with a duplexer and a second radio, a simplex Hotspot can be turned into a full duplex repeater.


Access Points, on the other hand, traditionally are small devices, again working with an internet-connected PC and with a low power transceiver chip in the device, obviating the need for an external transceiver. These devices typically operate in the 10 milliwatt range with small antennas plugged into the devices. They provide excellent coverage around the house and nearby environs. Manufacturers of these devices usually warn against using them with outside antennas (though some people do), since the design is not focused on protecting against strong RF or nearby lightening strikes.

Access Points are simpler to set up, are smaller and are ideal for what they were designed to do — provide close-by coverage and allow QSOs with other Hams over the network. They are really the cat’s meow when travelling — just bring along your HT, your Access Point, a tablet, laptop or Raspberry Pi and connect in using your phone’s or the hotel’s wifi.

Hotspots give you more coverage, so if you like to walk the dogs a mile from the house, you can have that QSO anyway. In some areas without access to full-sized ICOM repeaters, they allow you to provide mobile access to the D-Star network all around town or further. A more subtle payout is the learning and satifisfaction from successfully doing a Do It Yourself project.

Hotspot Information
More information about Hotspots is available here.  Note that page focuses on GMSK Modems, but other excellent modems are also available.  Multi-mode modems are also being developed.

Access Point Information
There are now several options for Access Points:

  • DVAP – (DV Access Point) by Internet Labs. Robin Cutshaw AA4RC and Moe Wheatley AE4JY of Internet Labs invented this category that has become extremely successful. It is well designed and really well supported. The DVAP works great with Robin’s software (DVAPTool) as well as other software, such as WinDV/ConDV, G4KLX, and FreeStar.
  • DVMEGA – Guus PE1PLM has designed a series of interesting products. His Access Point products include a Dual Band Radio shield (that fits on an Arduino board running the firmware) and a Dual Band Radio board for the Pi.
  • DV4mini – This small USB stick is a complete UHF access point that simply plugs into a computer, whether Windows or a Raspberry Pi.  It is multi mode and can talk to a D-Star radio, a DMR radio, a C4FM radio or a P25 radio.
Banner artwork by Philip "GilGildersleeve, W1CJD.   His cartoons adorned QST for many years.   I encourage you to get "Gil Cartoon Collection Download".