Diving into D-STAR

By Toshen, KEØFHS
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D-STAR logo
The D-STAR logo is a
registered trademark of Icom

1) Why bother?

When I first dove into D-STAR, I knew nearly nothing about digital voice and quickly found myself drowning in a big bowl of bewilderingly murky information soup. SOS!

So if it's that bewildering, why even bother?

I'll jump a bit ahead here and share one tidbit: at one point early in my exploration of D-STAR, I linked to a reflector and heard a guy in San Diego, California chatting with a chap in Yorkshire, England. That was the moment I became hooked!

Just think of it: worldwide communication with a Technician class license, a bit of effort and learning, and some fairly simple equipment.

Of course, the real goal isn't to just listen but to actually chat with people. This is the story of how I got there.

Today's amateur radio experimenter is as likely to use a keyboard as a soldering iron for experiments, and as a digital enthusiast, I can only cheer and encourage you to get involved and have some fun.
– Don Rotolo, N21RZ, Vocoding: Creating Digital Voice, CQ Amateur Radio

2) What is digital voice?

This section is a brief introduction to the basics of digital voice and hotspts, including links to some helpful websites, articles, and other content, in case you want to dive in more deeply. You also can find all the links together in a note at the end of this article: 6) Links to resources I've found helpful.

2a) Alphabet soup

As I was flailing around in the digital voice murkiness, one of the first things I figured out is that it's actually a bit like a big bowl of alphabet soup … it's absolutely crazy how many acronyms are floating around!

Bowl of alphabet soup with digital voice acronyms floating in it
Alphabetsoupese by Toshen, KE0FHS
Derived from an original photo
by Leo Reynolds. Some rights reserved.

Sometimes the acronyms are spelled out differently, for example, D-STAR vs DStar, or DVMEGA vs DV MEGA vs Dv-Mega, which makes searching for information more challenging. Other times, it isn't easy to determine what an acronym actually stands for, for example, in relation to digital voice I've seen DCS defined as Digital Call Server, Digital Communication Systems, and Digital Call Service, and I'm still unsure which is correct. (Perhaps it stands for Darn Confusing Stuff? ! )

Since there's no avoiding this craziness, you just have to accept it as part of the price of admission. And don't worry, by the end of this article, you'll be speaking "Alphabetsoupese" fluently!

2b) Multiple systems

The next thing I understood is that D-STAR is just one of several competing digital voice systems being developed, though it's the first.

The logos of D-STAR, DMR, System Fusion, and FreeDV

The Japan Amateur Radio League began development work on the Digital Smart Technologies for Amateur Radio (D-STAR) standard in the late 1990s and published it in 2001. It was developed specifically for amateur radio use, and started to gain traction in the U.S. around 2006.

The D-STAR standard has been adopted primarily by two first-tier amateur radio equipment makers, first by Icom, the D-STAR trailblazer, and more recently by Kenwood. By now, it's being used by tens of thousands of amateur radio enthusiasts worldwide.

It's also a mostly open standard (except for the vocoder software I discuss in the following "Alphabetsoupese - example 1" note), so it's being used for lots of experimentation, which means there's a bunch of interesting homebrew and small manufacturer hardware and software available.

Among the other digital voice systems being developed are DMR (Motorola, Hytera, Connect Systems, and others), and System Fusion (Yaesu).

There's also an open system in development, a combination of FreeDV software and an open source speech codec (vocoder), Codec 2. There's a version of FreeDV available for HF, but it hasn't come to the VHF and UHF frequencies yet. It'll be interesting to to watch their progress.

2c) Transceivers, repeaters, and reflectors (oh my)

Just as you can use regular transceivers in FM mode, you can use digital voice-capable transceivers in DV mode to talk directly from radio to radio simplex¹ or via a repeater (as long as it's a digital voice repeater).

Diagram of DV HTs connecting via simplex and via a DV repeater

[1] The DV simplex frequencies are 145.670 (2 M) and 446.225 (70 cm)

It gets even more interesting when digital voice repeaters are bridged together, enabling groups of two or more people, even far flung, to participate in something that is sort of like a conference call.

Diagram of DV HTs connecting via DV repeaters to a reflector

In the D-STAR world, this technology is called "Reflectors" (transmissions are reflected to all repeaters linked to the reflector), while DMR calls it "Talkgroups" and System Fusion calls it "Rooms."

Linking to reflectors to participate in a call or net is a big part of what playing around in the worldwide D-STAR playground is all about.

Here, too, there are multiple systems being developed and used simultaneously. Within just the D-STAR world, there are four main types:

  1. REF – The DPLUS reflector system, a proprietary system developed by Robin Cutshaw, AA4RC, is the first generation of D-STAR reflectors and still much in use, especially in English-speaking countries. An example is REF001 in London, referred to as D-STAR's "Mega Reflector." REF directory.
  2. XRF – The Dextra X-Reflector system, created by Scott Lawson, KI4KLF and now supported by Ramesh Dhami, VA3UV, is the second generation of D-STAR reflectors and is open source. An example is XRF720, which links several Colorado statewide D-STAR repeaters. XRF directory.
  3. DCS – The Digital Call Server reflector system, developed by Torsten Schultze, DG1HT, is an even newer system that is being used worldwide. An example is U.S. Reflector DCS006. DCS directory.
  4. XLX – The XLX reflector system, being developed by Jean-Luc Boevange, LX3JL, and Luc Engelmann, LX1IQ, is the newest system, which they describe as "the first and only multiprotocol Reflector system until now and supports all standard D-STAR protocols like DCS, Dextra and DPlus fully transparent." XLX directory.

To learn more about reflectors, read Reflections on Reflectors: A basic tutorial on DSTAR reflectors, 2016, by Bob Scott, W6KD.

2d) Personal access points (hotspots)

This is where it gets really exciting and fun, at least for me. One more piece of the puzzle is figuring out how to get onto the system when you're not within radio range of a digital voice repeater.

Diagram of DV HTs connecting via personal access points to a reflector and a DV repeater

Fortunately, there are innovative hams creating "personal access point" devices (a.k.a., hotspots) and software that enable a ham with internet connectivity to link directly to reflectors or DV repeaters, bypassing the need to transmit from the radio to a DV repeater first. Basically, these devices act as your own personal digital voice repeater and gateway.

There's another nice aspect of the personal access points: since you link directly to a reflector via a personal access point, you don't tie up a DV repeater the way you do if you use your radio to send a command to the repeater to link it via its gateway to a reflector for your personal call on that reflector. This may make a personal access point interesting even for someone who lives within range of a DV repeater.

i) Personal access point hardware

There are many different devices being developed to work with the different flavors of digital voice:

Here's a sampling of some of the "low-power" personal access point devices that are available as of Mar 2017:

For one ham's evaluation of some of these hotspots, see Amateur Radio Digital Hotspot Comparison (PDF), 2016, by Jeff, N8NOE.

ii) Personal access point software

Just as with the hardware, there's also all sorts of different applications available to run these devices:

3) Choosing a way forward

Given all the interesting options that are available, how do you actually choose which combination of radio, hotspot, and software to use?

Time to choose one of the forks in the path
Fork in a woodland path
by MarclSchauer, Shutterstock

For me, this involved first doing lots of reading and watching lots of videos (see the 6) Links to resources I've found helpful section below).

Then an Elmer tutored me. A shout out to Starr Aldrich, N0AES, President of the Longmont Amateur Radio Club, who generously spent a good bit of time patiently answering my questions.

Next I came across some enthusiastic hams in southern Colorado, the Parker Radio Association, who are doing some fun D-STAR-related work. They have a lot of good, up-to-date information on their Toolbox page, which helped me gain a broader perspective about digital voice.

The Charlotte Digital Radio Group is another group doing amazing work with digital radio, and they're also posting lots of good information: see their Contents page.

Finding all of these resources was a bit like being tossed a life saver … I'm still in the soup, but at least my head is now above water!

3a) Answering two key questions

Okay, one of the main things I've learned so far is that choosing a correct way forward comes down to answering a couple key questions, the most important of which is:

1) Who do I want to talk with and which systems do they use?

I already know that I want to be able to talk with groups that use D-STAR DPLUS Reflectors (REF) as well as FREE STAR* repeaters and Dextra X-Reflectors (XRF). Knowing that narrows my focus and eliminates personal access point devices that don't support linking to non-REF destinations.

Beyond that, as much as is practical I'd also like the flexibility to explore other systems, so the next key question is:

2) How close to the cutting edge can I travel comfortably?

On one end of the spectrum is today's world of personal technology, which pretty much spoils us. The most complicated thing we need to do is figure out which OS we want to buy into. Then we simply download and install some apps and at most tweak a few easy settings. After that, it all pretty much just works.

On the other end of the spectrum are the SuperNERD geniuses designing and soldering their own boards, and writing their own applications.

Unfortunately, I'm not a SuperNERD.

SuperNERD ... NOT!

While I'm willing to do some exploring closer to the cutting edge, I also know I should avoid solutions whose descriptions include terms like experimental or that require SuperNERD powers. For example, the description of MMDVM in one of the recent PRA presentations says "Requires deep experience in compiling and configuring software, and interfacing with hardware." Nope, not for me (at least, not right now; I'll take another look at MMDVM once it matures a bit more).

To begin with, I think I'll look for a solution that enables me to link to D-STAR REF and XRF reflectors, as well as to the FREE STAR* repeaters I know I want to access. I'll see how it goes from there.

3b) Before doing anything else

There are a couple registration processes that can take a few days to complete, so it's a good idea to get them started as soon as you can.

i) Register with the D-STAR Gateway System

To fully use the gateways on many D-STAR repeaters, you need to register with the D-STAR Gateway System, a system that shares callsign routing and other information across all the D-STAR repeaters within the system. It's easy enough to register, so it's worth doing this right away.

The registration form

ii) Optionally, register with CCS7 for DCS

If you're going to be using the DCS reflector system, you also need to register with an authentication and routing system called CCS7 (Callsign Communication System, 7-digit).

The DCS system uses the CCS7 ID number instead of your callsign, though its authentication service maps your CCS7 ID number to your callsign.

DCS is big outside of the U.S. and also can be found in the U.S., and the CCS7 system is now the authentication system for multiple systems.

You can register using the DMR User / Repeater Registration form. Yes, you read that correctly: DCS and several other systems now use the DMR registration form. For DCS, choose the individual registration, which is also for private hotspots and repeaters, and then select the CCS7 option.

3c) Choosing a D-STAR-capable radio

Because of my good experience with the Kenwood TM-V71A mobile radio, when I started getting curious about exploring D-STAR and then saw that Kenwood had recently released a D-STAR-capable HT, I was intrigued.

My HT: Kenwood TH-D74A

I suspected the TH-D74A might be a good choice for me, especially when I saw that the feature set also included APRS with built-in GPS, another area I'm curious to explore. Also nice: tri-band, bluetooth and USB connectivity, and IP54/55 weatherproofing. And it has a color screen, which isn't really necessary, but sure is sweet.

Once I got my hands on this radio, I quickly grew to like it. The interface is—for me—more intuitive than other radios I've tried. I find the way they've organized the menu system to be brilliant!

The menu screen for the TH-D74A

I did swap out the stock rubber duck for a Comet HT-224. One thing I didn't like about the new antenna was the gap left between the radio's antenna seat (5/8″ ID) and the HT-224 (3/8″ OD). I solved that by getting a $0.26 rubber gasket (3/8″ ID × 5/8″ OD × 1/16″ groove) at our local True Value.

TH-D74A with a rubber gasket around the HT-224 antenna

I sliced off one side of it with a razor blade, and it makes a perfect seal. It fits snugly around the antenna, and also fits down in the antenna seat opening nice and tight. Sometimes, you just get lucky! I think the gasket will help preserve the radio's IP54/55 weatherproofing, and it looks better, too, making the antenna look like a more natural part of the radio.

I think this radio is going to give me years of opportunities to explore and enjoy many areas of analog and digital communication.

That said, there also are a lot of good Icom D-STAR-capable HT and mobile radios available, many of which are more cost efficient, so have a good look around before making your choice.

Icom HT and mobile D-STAR radios

In addition, Icom makes a drool-worthy D-STAR base station (IC-9100) and mobile unit (IC-7100). Both are multi-mode (HF, VHF, and UHF).
Icom IC-9100 and IC-7100 radios

Icom also just announced (Feb 17, 2017) a new mobile D-STAR radio, the ID-4100A, which sounds quite interesting. Details are limited, but they're calling it a DV Gateway radio. It has a Terminal Mode to enable it to connect to D-STAR repeaters and reflectors via the internet, as well as an Access Point Mode to enable it to act as mid-powered (50 watt) hotspot.

3d) Choosing a personal access point device

I then needed to decide which personal access point device and software to use. That's when all the great information from Elmer Starr as well as some of the online info I came across really helped.

One thing that Starr recommended was trying a Raspberry Pi-based solution. That struck me as a good direction to head since I had never played around with an RPi but have wanted an excuse to try one out. As Thorin Klosowski writes in his Lifehacker.com article, What I’ve Learned From Tinkering With the Raspberry Pi for Five Years:

[T]he Raspberry Pi is far, far away from being as user friendly as a PC or Mac. That’s a feature, not a bug. The Raspberry Pi is built to force you to learn troubleshooting, and that’s still one of my favorite things about it.

So I went ahead and ordered a Raspberry Pi 3.

Next, based on some good comments I read online, I decided to complement the RPi with the DVMEGA.

DVMEGA-DUAL

For maximum flexibility, I chose the DVMEGA-DUAL, which operates on both VHF and UHF frequencies (however, I've only ever used UHF frequencies, so the less-expensive DVMEGA-UHF would've been fine).

I like it that this combination can work with DPLUS reflectors, X-Reflectors, DCS reflectors, and FREE STAR* repeaters. I also like it that it's a possible mobile solution, as it can operate headless using radio commands, tether to a cellular hotspot via WiFi, and operate on a portable battery pack.

Later, I may want to explore further and try a solution that lets me cross-link to DMR talkgroups and possibly System Fusion rooms, but for now I think DStar Commander and the DVMEGA will provide a good launch pad for my exploration of digital voice.

4) Rolling up my sleeves

Okay, time to put it all together.

4a) Putting together the hardware foundation

The Raspberry Pi 3 arrived first, so I started playing around with it.

Raspberry Pi 3

I got it assembled and running, connected it to my WiFi, and started exploring the Raspbian OS that came with it. I'm impressed with what this little credit card-sized device can do, including driving a spare 24″ LCD monitor I have (I've seen some old, full-sized Windows desktop computers that can't handle that!). It even includes LibreOffice, which is my favorite office suite. Nice!

4b) Creating the DStar Commander image

Next I created a microSD card with the DStar Commander image.

MicroSD card

As of Jan 2017, not all images that currently are available online for hotspots that use an RPi have been upgraded to work with the new RPI 3, even though it was released nearly a year ago. The good news is that DStar Commander's image already has been upgraded to work with an RPi 3. Nice!

  1. Download and install a disk imager. I didn't have a utility to write (a.k.a., burn or flash) the image to my microSD card, so I downloaded and installed the Win32 Disk Imager program onto my Windows PC.
  2. Download the image file. Next get the appropriate image zip file from the W6KD forum: DStar Commander Public Release Download. For the DVMEGA, download the DStarCommander_V2.01_dvMega.zip file. There's also one available for DVAPs.
  3. Extract the zip file. It contains:
    • A READ_THIS_FIRST.pdf file. It's a good idea to read this as it explains how to choose which method to use to configure the image with your settings.
    • The DStarCommander_V2.01_dvMega disk image file. This is the actual image that gets written to the microSD card.
    • The DStarConfig application. This is an app you can run to easily configure the image with your settings after you have written the image to the microSD card.
    • A Docs folder. This contains three PDF documents that explain the the three methods you can use to set up DStar Commander:
      1. Interactive PC-Based Setup. This is the full setup that uses the DStarConfig app.
      2. Headless Basic Setup. This is a basic setup that enables use of a few radio commands to run DStar Commander.
      3. Manual Setup. This is the method for reconfiguring the setup later, if necessary.
  4. Insert the microSD card into the PC and make a note of which drive it is plugged into; in my case, it was E:\.
  5. Open the Win32 Disk Imager, select the drive, select the disk image file, DStarCommander_V2.01_dvMega, and then click Write to flash the image to the microSD card
    Win32 Disk Imager ready to write to the microSD card
  6. Run the DStarConfig program to customize the DStar Commander setup. It's a good idea to read the Interactive PC-Based Setup PDF document first, so you can have all the answers ready.

Once again, I'm impressed; this is a well thought out solution.

The DVMEGA should arrive in a couple days, and then I'll see if the optimism I'm currently feeling is really warranted.

4c) Programming the radio

While I was waiting for the DVMEGA to arrive, I went ahead and started programming my radio for use with the personal access point. While this section is focused on the Kenwood TH-D74A as well as the Kenwood MCP-D74 Memory Control Program, it contains information that anyone setting up a radio for use with a personal access point might find helpful.

Apologies right up front! This is the most information dense section of this article. But I think it's valuable information, so grab a cup of coffee or tea and take a deep breath.…

Note: If you want to skip past all this radio programming nitty-gritty, here's a link to the next section: 4d) Booting up the DVMEGA.



Radio programming TOC

[1] Initial D-STAR-related setup
[2] Set up radio for using a personal access point
  [a] For DR & DV mode: Personal access point frequency
  [b] For DR mode only: Add personal access point to repeater list
    • Add a repeater via the MCP-D74A software
    • Add a repeater directly in the radio
  [c] For DR & DV mode: Create op channels for basic D-STAR actions
  [d] Create op channel for reflector or repeater
[3] Additional radio programming notes
  [a] Using the U, E, I, and linking memory channels
  [b] Using CQCQCQ
  [c] Reusing the CQCQCQ, U, E, and I memory channels
  [d] Linking to repeaters with shorter callsigns
  [e] Organizing the memory channels
 


[1] Initial D-STAR-related setup

Even though I'm focused on setting things up for a personal access point, there are a couple aspects of programming the radio that apply to everyone using D-STAR, like MY CALL and TX MESSAGE.

MY CALL. The very first thing everyone using D-STAR needs to do is to enter their callsign in the MY CALL field of their radio. In the TH-D74A, that's done in Menu 610: D-STAR » TX/RX » My Callsign. Enter your call sign in the lefthand field, and a four-digit "memo" in the righthand field, for example, your radio model (I used "D74A") or your name.

TX MESSAGE. In the same TX/RX submenu, you also can enter a brief TX MESSAGE phrase (up to 19 characters) to be transmitted to people, repeaters, and reflectors receiving your call. I entered my name and hometown: Toshen - Lyons, CO.

[2] Set up radio for using a personal access point

The basic method for linking to and using reflectors and repeaters via a personal access point is to:

  1. Link to the reflector or repeater via the personal access point.
  2. Use CQCQCQ to chat.
  3. When finished, unlink from the reflector or repeater.

Since this is a wash, rinse, and repeat type of cycle, it also can be very helpful to set up frequently used repeaters, reflectors, and various D-STAR-related commands in memory channels.

[2a] For DR & DV mode: Personal access point frequency

To access the DVMEGA with the TH-D74A, I decided to go ahead and use the default 431.00 UHF frequency, which as far as I can tell is normally unused in my area. Since the transmission between the two devices is very short range, I set the radio's output power to EL (0.05 W).

[2b] For DR mode only: Add personal access point to the repeater list

Note: This is a long step. If you're setting up for DV mode, you can skip to the next step: 2c] Create op channels for basic D-STAR actions.

The first thing to do is to add your personal access point to your repeater list. I read about various ways that this can be done, but the only way I could get it to work was by using a method that Ed Woodrick, WA4YIH, the guy behind D-STAR Info, explained in a post in the Kenwood_TH-D74 group. Thanks, Ed!

Add a repeater via the MCP-D74A software

The method I ended up using was to first add a personal access point to the Repeater List via the Kenwood MCP-D74 Memory Control Program. Once I added the first one and wrote the data to the transceiver, I was able to add additional ones either via the MCP-D74 app or directly in the radio.

To add a hotspot to the repeater list via the MCP-D74A app:

  1. Save a copy of the radio's data:
    1. Open the Kenwood MCP-D74 Memory Control Program.
    2. Connect the TH-D74A via USB cable to the computer, and then turn the radio on.
    3. Read data from the transceiver.
    4. Save the profile as a backup, and then save a different copy to work in.
  2. Import an updated Repeater List from D-STAR Info:
    1. Open the Repeater List Downloads for DR Mode Radios page.
    2. Enter a location, for example, your city, and click Lookup Location.
    3. Select radio model in the drop-down list.
    4. The TH-D74A can store 1,500 repeaters in its Repeater List memory, but you should leave some repeater slots unused. I chose to leave 20 unused, but 50 - 100 might be better if you travel a lot.
    5. Click Download and save it to your computer as a .tsv file.
    6. In the MCP-D74 program, select Repeater List in the left pane, and then click Import Repeater List from File.
      MCP-D74: Import Repeater List from File
    7. Find the tsv file you downloaded and import it.
  3. Add the personal access device to the imported Repeater List. Because you imported a regional Repeater List, there will be spare World Regions, Countries, and Groups.
    1. First, create a new virtual World Region, Country, and Group by clicking Edit Area.
      MCP-D74: Edit Area button
      Add the names (I used the last empty field in each list and used the name "Hotspots" for all three), and then click OK.
      MCP-D74: Edit Area dialog box with new Hotspots World Region, Country, and Group added
    2. Scroll to the first empty row at the bottom of the repeater list, and then enter the info for the personal access device, starting with the frequency. Here are my entries for the DVMEGA:
      • Frequency: 431.000
      • Name: DVMEGA
      • SubName: DVMEGA DUAL
      • World Region: 6:Hotspots
      • Country: 150:Hotspots
      • Group: 300:Hotspots
      • Callsign (RPT 1): KE0FHS B
        (Note: B = using UHF frequency with the DVMEGA)
      • Gateway (RPT 2): KE0FHS G
      • Lockout: Not checked = Off
      • Shift: Plus
      • Offset: 0.000.00
        (Note: Yep, + Shift, 0 offset, which for some reason isn't the same as no shift.)
    3. Optionally, you can add location information by selecting the row the personal access point is on and then clicking Edit Repeater. In the dialog box that opens, you can add the following information that's not available by default in the main list view:
      • Position Accuracy: Approximate/Exact
      • Latitude in Degrees Minutes: N/S 00°00.00'
      • Longitude in Degrees Minutes: E/W 000°00.00'
      • Time Zone: UTC +/−00:00
    4. Save the profile.
  4. Write the data to the transceiver.

[2c] For DR & DV mode: Create op channels for basic D-STAR actions

Create four operating channels for the basic D-STAR actions in the TH-D74A to be used with the DVMEGA, all in DR or DV mode, depending on which you've decided to use.

  1. In VFO FM mode, select the frequency to use, in my case: 431.00.
  2. Press Mode until you're in Digital mode, either DV or DR.
  3. If you need to switch to the other mode:
    1. Press [F] then Digital to open the Digital Function menu.
    2. Navigate to 5. DV/DR Select.
    3. Press A/B = OK to change to the other mode.
  4. For DR mode only: Select the DVMEGA via Repeater Select:
    1. Press and hold the Multi-Scroll Down Arrow to open the Repeater Select screen.
    2. Choose Repeater List and press ENT.
    3. Navigate to the DVMEGA and press ENT.
  5. For DR & DV mode: Create a CQCQCQ operating channel for talking once a link to a reflector or repeater is established (Note: The last two spaces of the UR CALL field are intentionally left blank):
    For DR mode only:
    1. Press and hold the Multi-Scroll Up Arrow to open the Destination Select screen.
    2. Use one of two options:
      • Choose Reflector, press ENT, choose Use Reflector, and then press ENT again. This populates the URCALL field with CQCQCQ.
      • Choose Direct Input (URCALL), press ENT, type CQCQCQ, and then press ENT again.
      • Note: Do NOT use the Local CQ option for talking after linking to a reflector or repeater using a personal access point; although this will populate the URCALL field with CQCQCQ like the other options, it also will change the Rpt 2 field, with the consequence that others will not be able to hear you.
    3. Important! Save per the following Method to save a channel to memory.
    For DV mode only:
    1. Press [F] then [Digital] to open the Digital Function Menu, select 1: Destination Select, and then press ENT.
    2. Choose Direct Input (URCALL), and then press ENT.
    3. Type CQCQCQ, and then press ENT again.
    4. Important! Save per the following Method to save a channel to memory.
  1. For DR & DV mode: Create the remaining three basic D-STAR action operating channels (Note: blank spaces are shown here with the symbol ):
    1. Start with the first four (DR mode) or three (DV mode) steps above.
      (Hint: You also can use the shortcut of saving a copy of an existing D-STAR action operating channel, like the CQCQCQ channel you just created, to a new memory channel, after which you can load the main frequency screen with the memory channel's settings and then revise them per the following steps.)
    2. For DR mode only: Press and hold the Multi-Scroll Up Arrow to open the Destination Select screen.
      For DV mode only: Press [F] then [Digital] to open the Digital Function Menu, select 1: Destination Select, and then press ENT.
    3. Choose Direct Input (URCALL) and press ENT.
    4. Create the following operating channels. Set up one at a time, save it to a memory channel, and then set up the next one:
      • Unlink = Use to unlink from a reflector or repeater (you should always do this when you're finished).
        Type 7 blank spaces () followed by U:
        ⊔⊔⊔⊔⊔⊔⊔U
      • Echo test (optional) = Use to perform an echo test (when using a personal access point device, the echo test is with that device, not the reflector or repeater).
        Type 7 blank spaces () followed by E:
        ⊔⊔⊔⊔⊔⊔⊔E
      • Info request (optional) = Use to request status information (when using a personal access point device, the request for status information is to that device, not the reflector or repeater).
        Type 7 blank spaces () followed by I:
        ⊔⊔⊔⊔⊔⊔⊔I
    5. Save per the Method to save a channel to memory above.

[2d] For DR & DV mode: Create op channel for reflector or repeater

To link to and use a reflector or repeater via a personal access point, begin with the first four steps in the previous procedure (or use the memory channel copy shortcut), and then:

  1. Select the destination repeater or reflector via Destination Select:
    1. For DR mode only: Press and hold the Multi-Scroll Up Arrow to open the Destination Select screen.
      For DV mode only: Press [F] then [Digital] to open the Digital Function Menu, select 1: Destination Select, and then press ENT.
    2. Choose Direct Input (URCALL) and press ENT.
    3. Enter the link command for the reflector or repeater.
      For example, for the PRA D-STAR X-Reflector: XRF223BL = transmit a link request (L) to the B module of the XRF223 reflector.
  2. Optionally, for a repeater or reflector you're going to frequently link to and use via the personal access point, save per the Method to save a channel to memory above.

4d) Booting up the DVMEGA

When the DVMEGA board arrived, I mounted it on the Raspberry Pi, inserted the microSD card with the DStar Commander image, screwed on the little stubby antenna, fired it up, and performed a successful echo test!

DVMEGA-DUAL mounted on Raspberry Pi 3

Tweaking the setup. Perform these next steps at your own risk. They all worked fine for me, but it's possible they might mess up your DStar Commander image. (Of course if that happens, you can always flash a new image; I flashed a new image probably at least two dozen times when I was experimenting with these tweaks!)

Important! Do NOT change the time zone. This seems counterintuitive to me—I would think you'd need your own time zone on the device for things to work properly—but if you do change the time zone, the DStar Commander radio commands will no longer work.

  1. To update and upgrade the components included with the image, run:
    sudo apt-get update
    and
    sudo apt-get upgrade
    Note: The upgrade step takes a long time to run.
  2. Run
    sudo raspi-config
    and make the following changes:
    • Expand the filesystem to provide maximum room on the microSD card for log files, etc.
    • For enhanced security:
      • Change your user password.
      • Change the boot option to B3: boot to Graphical User Interface (GUI) and require password to log in. (Note: If you want to run headless, don't require a password to log in.)
      • Under advanced options, turn SSH off. (I'm using a connected monitor, so this makes sense for me; obviously, don't do this if you need to SSH into your RPi.)
  3. To create a separate root password, run:
    sudo passwd root
  4. Install the Chromium web browser to replace the default Midori browser (which I read is no longer being maintained). See the note: 7c) Installing the Chromium web browser.
  5. Optionally, if you need to link to D-STAR or FREE STAR* repeaters, create a special hosts file with entries for those repeaters. See the note: 7d) Creating and editing DPlus_Hosts.txt file.
  6. Finally, update the reflector list using the appropriate radio command. See the note: 7e) DStar Commander radio commands.

4e) A case for ruggedness

To prepare the DVMEGA and Raspberry Pi for inserting into a case, I added some hot glue to the end of the standoff, as well as to the seam between the DVMEGA connector and the GPIO pin header on the RPi in order to make the whole thing a bit more stable. (Since the antenna mount is in the corner diagonally across from the connector, if the connector isn't glued down, the standoff acts like a pivot: if you touch the antenna, the connector tends to lift off the GPIO pin header.)

Finally, I customized an aluminum Flirc case for use with the RPi/DVMEGA combo. I used my Dremel to cut away the extruded heatsink to make space for the DVMEGA board, but that's okay because I had read that the RPi 3 runs a bit hot so already had mounted a heatsink directly onto the main RPi chip between the RPi and DVMEGA boards.

DVMEGA and Raspberry Pi inside Flirc case
The USB dongle is for a wireless keyboard/touchpad
I'm using when the RPi is connected to a monitor.

I also drilled a hole in the case for the antenna, a small hole so I can see the DVMEGA LED, and then two more small holes so I can see the the RPi LEDs (the case originally was designed for the RPi2, which has its LEDs in a different location than the RPi3). I ended up with a nice, rugged setup.

5) And it worked: QSO on a reflector!

All the intense studying and hard work over the past couple of weeks paid off when I was able to join my first D-STAR net! The hams on the net were kind enough to share some good advice with me and to suggest a good list of reflectors I can start linking to so that I can begin meeting other hams around the world.

I'm ecstatic!

Here are the settings I used:

To link:
Mode: DR
Frequency: 431.00
via Destination Select » Direct Input (URCALL):
UR CALL: XRF223BL
via Repeater Select » DVMEGA hotspot:
RPT1: KE0FHS B
RPT2: KE0FHS G
MY CALL: KE0FHS

To chat:
Frequency: 431.00
Mode: DR
via Destination Select » Direct Input (URCALL):
UR CALL: CQCQCQ
via Repeater Select » DVMEGA hotspot:
RPT1: KE0FHS B
RPT2: KE0FHS G
MY CALL: KE0FHS

5a) Linking to a D-STAR repeater

The next step was to figure out how to link to a D-STAR repeater that has a net with which I want to participate. It's funny to think that when you're using a personal access point, linking to repeaters is more challenging than linking to reflectors, but while a list of reflectors is stored in an easily updatable file that's included with DStar Commander, you must manually add entries for repeater TCP/IP addresses in a special hosts file. I tried doing this, but couldn't get it to work.

Elmer Starr to the rescue again! He figured out that I wasn't creating the special hosts file in the actual root directory (due to my ignorance with Linux). He quickly set me on the right path, and we were soon chatting via the repeater. Thanks once again, Starr!

See the Notes section below for more info about creating the special hosts file, DPlus_Hosts.txt, and adding the TCP/IP entries to it.

Then Starr signed off saying: "Okay, now you need to learn D-RATS," which is a text messaging and file transfer application for D-STAR that is used by our local ARES organization, BCARES.

Ha! Just when I thought I could rest for a few minutes!

5b) Just can't wait to get on the road again!

Here's one way you can have some digital voice fun while traveling.

On the road in Colorado
Countryside road, fall season in Colorado
by f11photo, Shutterstock

There is a little (2″×1.5″) board called the BlueStack-Micro-plus that you can mount under a same-sized DVMEGA board that is made for the RPi, but in the case, the RPi isn't used.

DVMEGA-DUAL board mounted on BlueStack boardThis duo can be paired with an app called BlueDV. (The photo shows a DVMEGA-DUAL mounted on the BlueStack.)

So far, I've used the BlueStack-DVMEGA-BlueDV combo while participating in D-STAR nets on an XRF reflector, as well as while chatting on London's REF001 C Mega Reflector. It works well.

Mode 1: Ser2net via USB cable. The BlueStack-DVMEGA duo can be connected via USB cable to a Windows PC running the BlueDV app. In this configuration, the power is provided from the PC's USB port. To use the BlueStack this way, its Serial Port to Network Proxy (ser2net) mode must be activated, which means the S1 switch (red button) must be engaged (in the latched-in position).

Mode 2: Bluetooth. The BlueStack-DVMEGA duo also can be connected via bluetooth to an Android phone running the BlueDV app. In this configuration, the power can be provided by a battery pack or a power supply. To use it this way, its Bluetooth mode must be activated, which means the S1 switch (red button) must be disengaged (in the popped out position). When used with a battery pack, this is a good mobile solution. Most likely it also can be run off a cigarette lighter USB port, but I haven't tested that configuration yet.

DVMEGA & BlueStack in custom case
I made a case for the BlueStack-DVMEGA duo
out of some mahogany scraps

On the road! I used this mobile solution to participate in a net while driving back along the foothills from the annual BCARES meeting in nearby Boulder, Colorado. It worked really well. The only issue I had was when I hit the one spot along the highway where it goes between two hills (I always lose cellular service there). As I passed that spot, I first heard a few seconds of R2D2-type garbled voice, and then I lost all audio for a few seconds, but the BlueDV app held onto the link, recovering nicely as soon as I was back in cellular range.

During the rest of the net, the audio was nice and clear in both directions (I've consistently heard from receiving stations that the audio from my TH-D74A over D-STAR is loud and clear with a good tone). I checked my data usage this morning (I use Google Fi) and it looks like I used only about 12 MB for the 40-minute net.

Thanks, The Nederlands! The BlueStack, DVMEGA, and BlueDV are made by various hams in The Nederlands. Individual boards and complete kits are available from Combitronics in Wernhout, and can be shipped internationally. There's information about the various versions of the BlueDV app, made by David, PA7LIM, on the BueDV website. BlueDV for Android can be downloaded directly onto an Android phone from the Google Play App Store.

The only limitation I've found compared to using the DVMEGA mounted on an RPi and running DStar Commander is that there's no way I've been able to discover to connect to a D-STAR repeater, only reflectors.

5c) The tail end of the D-STAR tale …

I thought my D-STAR story was headed for a fairy-tale ending, but I should've known better … D-RATS tail got caught in d-trap.

The rat's tail caught in a trap!
Toon mouse
by Jeff Cameron Collingwood, Shutterstock

After installing the D-RATS software on my Windows PC and configuring it per the D-RATS Operating Guide (0.3.3), I attached my Kenwood TH-D74A HT to the PC via USB cable with a great sense of fanfare … and then fell flat on my face.

I could see other stations signed into D-RATS and could receive their texts, but they couldn't see me and I couldn't successfully send texts to them.

Turns out my texts weren't triggering a PTT in my TH-D74A. But why not? After scouring the online forums, I learned that there's a problem related to this with the TH-D74A. People have reached out to Kenwood about the issue, but there has been no definitive answer back yet.

Rats!

To be continued (hopefully) …

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