Diving into D-STAR – TH-D74A

Revised: May 2021, CC BY-SA
Firmware: v1.09 · MCP: v1.03

Programming the TH-D74A for D-STAR

While this section is focused on the Kenwood TH-D74A as well as the Kenwood MCP-D74 Memory Control Program, it contains some information that anyone setting up a radio for use with a D-STAR hotspot might find helpful.

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

Hint: As an alternative to this detailed article, Craig, W1MSG, has a short video that'll get you up and running quickly: Kenwood TH D74A for Hotspot use.

Hotspot note: If you're going to be using a hotspot for D-STAR, it's really important that you set up your radio properly. For most hotspot devices, DV mode won't work; instead, you must set up RPT1, RPT2, and a zero offset (either +/−0.000). This is known as Duplex mode or D-STAR Repeater (DR) mode.

Disclaimer:  These are my personal notes based on my experience setting up my own TH-D74A, specifically for use with my ZUMspot, MMDVM_HS_Hat, and DVMEGA hotspots. I've tried everything here and it works, but there also are other methods, which you can find by searching online. If anything needs correcting, please let me know.

1) Initial D-STAR-related setup

Even though I'm focused on setting things up for a hotspot, 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 CALLSIGN in the lefthand field, and a four-digit "MEMO" in the righthand field, for example, your NAME or RADIO MODEL (I used "D74A").

Important! For best results, use UPPERCASE letters in the My Callsign field (Menu 610), both for the callsign and memo. Some reflector systems won't properly decoded miXeD CaSe entries. Thanks to Dave, N6XVZ, for this hint.

Note: Peter, AE5PL, posted in the Pi-Star User Forum about the MEMO field, explaining that it was part of the original D-STAR protocol spec and was called the "own callsign extension," and was intended "to provide for international reciprocal operations where the country being visited requires the inclusion of their prefix in the transmitting callsign identification." However, it now gets used for other things like names or radio models.

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 hotspot

The basic method for linking to and using reflectors and repeaters via a hotspot is to:

1. Link to the reflector or repeater via the hotspot.
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) DR & DV mode: Hotspot frequency

To access my hotspots with the TH-D74A, I decided to use the 438.600 UHF frequency, which as far as I can tell is normally unused in my area, and is one of the frequencies recommended in the Colorado CCARC Guidelines on Hotspots (frequencies that are intended for short distance operation using low power devices). Since the transmission between the two devices is very short range, I set the radio's output power to EL (Economic Low: 0.05 W), which is plenty even when I'm in a different room from the hotspot.

Note: For help choosing a frequency, see your country's band plan (U.S. Band Plan) or the helpful info that Ron, VE1AIC, has posted on his blog: Digital Voice frequencies.
Important! Avoid frequencies used for other purposes, especially for satellites, for example, 435.00 - 438.00 (used for satellites internationally), as satellite communication can be disrupted easily by low power transmissions, such as those used for digital voice. (Hotspots running firmware ZUMspot/MMDVM_HS v1.4.12 or later won't work on those frequencies.)

2b) DR mode only: Add hotspot to 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 hotspot 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 hotspot 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-D74 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.
      
   7. Find the tsv file you downloaded and import it.
3. Add the hotspot 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.
      
      Add the names (I used the last empty field in each list and used the name "Hotspots" for all three), and then click OK.
      
   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. For example, here are my entries for the DVMEGA:
      
      • Frequency: 438.600
      • 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 (sometimes referred to as "Duplex mode")
        Important! You read that right! Plus shift, zero offset, which for some reason isn't the same as no shift.
   3. Optionally, you can add location information by selecting the row the hotspot 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.
   

Add a repeater directly in the radio

Once you've added the virtual World Region, Country, and Group, and then have written the data to the transceiver, they'll be available in the radio, so optionally you can add more hotspots to the repeater list right in the radio:

1. In DR mode, press Menu.
2. Menu 210 = Memory > Repeater List > View List and press ENT.
3. Choose a World Region (I chose Hotspots) and press ENT.
4. Choose a County (Hotspots again) and press ENT.
5. Choose a Group (Hotspots again) and press ENT.
6. Press Menu to open the Repeater List Menu.
7. Choose Add and press ENT.
8. Next, add the appropriate values to all of the fields.
9. Finally, press Write to save the entry to the Repeater List.

Hint: You also can edit a repeater that's in the Repeater List, but only if it's not selected as the current operating channel.

2c) DR & DV mode: Create op channels for basic actions

Create four operating channels in the TH-D74A for the basic D-STAR actions (CQCQCQ, echo test, info, and unlink) to be used with the hotspot, 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: 438.600.
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. DR mode only: Select the hotspot 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. 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):
   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 hotspot; 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 note below: Method to save a channel to memory.
   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 note below: Method to save a channel to memory.

6. 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. DR mode only: Press and hold the Multi-Scroll Up Arrow to open the Destination Select screen.
      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 = Used 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) = Used to perform an echo test (when using a hotspot, the echo test is with that device, not the reflector or repeater).
        Type 7 blank spaces (⊔) followed by E:
        ⊔⊔⊔⊔⊔⊔⊔E
      • Info request (optional) = Used to request status information (when using a hotspot, the request for status information is to that device, not the reflector or repeater).
        Type 7 blank spaces (⊔) followed by I:
        ⊔⊔⊔⊔⊔⊔⊔ I
      • Note for echo tests and info requests: When linking directly to a repeater (not via a hotspot), the repeater's callsign should be entered followed by E or I in the 8th position. Thanks to Dave, N6XVZ, for pointing this out.
   5. Save per the note above: Method to save a channel to memory.

2d) DR & DV mode: Create op channel for reflector or repeater

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

5. Select the destination repeater or reflector via Destination Select:
   
   1. DR mode only: Press and hold the Multi-Scroll Up Arrow to open the Destination Select screen.
      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, XRF223BL = transmit a link request (L) to module B of the XRF223 reflector.
6. Optionally, for a repeater or reflector you're going to frequently link to and use via the hotspot, save per the note above: Method to save a channel to memory.

3) Additional radio programming notes

A few more notes related to programming and using a D-STAR radio.

3a) Using the U, E, I, and linking memory channels

To use these channels, you select them and then push PTT for at least one full second ("one, one thousand").

3b) Using CQCQCQ

When using the CQCQCQ channel, you press PTT to talk just as you would with any radio call, but because there can be a slight delay before the transmission is established, you should push and hold PTT, pause at least one full second, and then begin talking. If you don't pause, your first words likely will get cut off.

3c) Reusing the CQCQCQ, U, E, and I memory channels

You can reuse these channels with all of the reflectors and repeaters that you link to via the hotspot. So when you want to add another reflector or repeater into memory, you need to add only the specific link request.

3d) Linking to repeaters with shorter callsigns

If you're linking to a repeater with a callsign shorter than six digits, leave enough blank spaces (⊔) between the callsign and the module + link letters to put the L in the eighth space, for example:
KC0DS⊔CL = Transmit a link request (L) to the VHF module (C) of the KC0DS D-STAR repeater.

When you enter a 5-digit callsign like this example, put one space (⊔) between the callsign and the "CL" letters. For a 4-digit callsign, put two spaces (⊔⊔).

3e) Organizing the memory channels

Since I'm adding a lot of reflectors and repeaters into my memory channels that I'll be linking to via my hotspot, it became important to organize my memory channels well.

I have set them up in blocks of ten. The first channel in a block is a CQCQCQ talk channel, and the second is an unlink channel. Then the remaining eight channels in the block are reflector or repeater linking channels. That way, I can:

1. Select a linking channel.
2. PTT to link.
3. Quickly select the nearest CQCQCQ channel and chat.
4. At the end of the call, select the nearest unlink channel and PTT to terminate the link.

Since I don't often use the optional echo test and info request commands, I added them only to the first block of ten.

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