D-PRS Setup for ICOM D-STAR Radios
aprs.fi D-STAR Filters
External GPS Antenna Alternative for IC-2820
Icom D-STAR Mobile Radio Mic Extension Alternative

D-PRS is the act of converting Icom GPS information generated by Icom D-STAR radios in NMEA/GPS mode into TNC2 formatted APRS strings. It is important to note that D-PRS is not a protocol but a conversion specification. - Peter Loveall AE5PL


NMEA/GPS mode uses a 3-line format and a calculated simple XOR checksum for the identification line.

D-PRS Setup for ICOM D-STAR radios using NMEA/GPS mode
Refer to the radio's manual for specific GPS setup information.

Radio Configuration:

Select GPS TX to GPS or DVG mode depending on model of radio.

Enable $GPGGA and $GPRMC GPS sentences only. (Both of these GPS sentences provide position while $GPRMC provides speed and direction, and $GPGGA provides altitude).

Now use the D-PRS Message Calculator. Enter the D-STAR callsign that you will be using. (If you're using an SSID, make sure that it is in the eighth position and do not use A, B, C, D, G, S, zero, or space).

The GPS message can be whatever you'd like, up to 13 characters (ie: JOE'S TRUCK). Letters are caps only.

Enter the contents of the box "Input into TX Message C1:" into your radio. (GPS message on the IC-2820 and IC-91AD, TX message C1 channel on the ID-800H, TX GPS Message on the ID-80AD & ID880H). Be sure to enter the correct number of spaces between the symbol code and the text/checksum.

Set the automatic GPS message transmission to OFF .

Set your RPT2 in the callsign menu to allow for gateway operation by adding the letter 'G' in the eighth position. (ex: AA1HD  G).

Make a "successful" transmission through your local D-STAR repeater with gateway access.

Now enter your D-Star Station Callsign-SSID (ex: WY1U-M)  and click here to view the jFindu locator site. If not using an SSID, just enter your callsign.
You should now see your callsign and icon as entered above, along with your current location coordinates under Last Heard on DSTAR. If you don't see your callsign....carefully re-check the above steps and refer to the additional notes below.

Additional Notes:

While any radio is in either GPS or DPRS/GPS-A mode, it cannot be used for standard low speed data.

Refer to the radio's manual for specific GPS setup information.

The GPS-A "format" does not support altitude (/A=000121 for instance).
For your altitude to be seen, you will need to run in NMEA/GPS mode with the RMC and GGA sentences enabled.

You will not not show up if the GPS sentence indicates the GPS is not in lock. On the IC-2820 display, the GPS icon should not be blinking. Be sure your GPS antenna is in the clear and far enough away from the radio's transmitting antenna.

Be sure you have the correct number of spaces between the symbol code and the text/checksum.

You must set your RPT2 to allow for gateway operation otherwise you will not be gated to APRS-IS.

Make sure that the radio is in NMEA/GPS mode and not DPRS/GPS-A mode. (IC-2820H display shows DV-G in upper left corner of display).

If you're using an SSID, make sure that it is in the eighth position in your radio's callsign memory (ie: WY1U _ _ _ M)
*Due to D-STAR repeater design, do not use A, B, C, D, G, S, zero, or space.

On capable radio's, the position display of a received signal is available only if the transmitting station is using NMEA/GPS mode in which RMC and GGA sentences are enabled.


Icom's DPRS/GPS-A mode uses a one line format and includes a CRC.

D-PRS Setup for ICOM D-STAR radios capable of using DPRS/GPS-A mode
Refer to the radio's manual for specific GPS-A setup information if available.

Radio Configuration:

You do not need to set a GPS message per the D-PRS Calculator page.

Set UNPROTO to APInnn,DSTAR* (where nnn is the first 3 digits of the radio model number. See table below).

In the case of the handhelds (only 2 digits), you may optionally use the first character following the model number (92AD would be API92,DSTAR* or API92A,DSTAR*).

UNPROTO Settings

FYI: DPRS/GPS-A does not pass altitude information to APRS-IS. For more info on D-PRS, please visit AE5PL's D-PRS page.

* The 880H does not send the front panel message as part of the NMEA/GPS mode data (they removed it from this model for unknown reasons). For DPRS to be used with this model of radio, you must use DPRS/GPS-A mode and it does not support altitude reporting. Later model radios (the 31 and 51 handhelds) do support altitude reporting in DPRS/GPS-A mode. The D-PRS specification (that is what I am the author of) was developed around Icom's proprietary use of the "unused" data portion of the DV bit stream (the "serial" data is actually encapsulated within that unused portion of the bit stream). The key word is "proprietary" which means they can do pretty much anything they want to. They quit including the front panel message in NMEA/GPS mode with the 880 models but didn't add altitude in DPRS/GPS-A mode until the 31 model. They added the ability to have a different station identification in DPRS/GPS-A mode with the 31 so the uniqueness and equivalence depended on in D-PRS can be broken by misprogramming the newest radios. Icom did not develop the D-PRS specification and they periodically do things as described above that reduce the functionality of their radios with regards to D-PRS and non-Icom software. I believe most of those omissions and changes are simply a lack of understanding by the Icom engineers as their focus tends to be on the hardware and D-STAR specific aspects of the radios. -Pete AE5PL

DSTAR Only Filter on aprs.fi

To Create "D-STAR ONLY" Filters on aprs.fi

Log in to your account on APRS-FI

Click on the Filter icon in the upper right, this opens a pop-up of the filter list

Click the + at the bottom of the pop up

Select Type on pulldown & add the following filters (one at a time) saving each filter:

Filter Type - Packet Path


Filter Type - Destination Callsign


Your Filter List should now look like this:

To Filter out DRATS stations:
Click the Red down arrow next to the APRATS filter adding it to the bottom ----and not---- area.

Click the "Save as new List" button and name it whatever you wish (ie: D-STAR Stations Only)

With this filter you can show/hide per Repeater D-STAR "Modules" (A, B or C) , DRATS stations & DPRS stations per filter selection.

Waterproof external GPS Antenna for IC-2820

The Gilsson part #MCX Amplified GPS Antenna with 90 degree MCX connector can be used in place of the "non-waterproof" ICOM GPS antenna that comes with the UT-123.


You will also need a Female-Male MCX adapter that has a straight MCX male connector body that will fit thru the case of the IC-2820 into the external GPS jack.

Alternative Mic Extension for Icom IC-2820 and ID-800H

Instead of the Icom mic extension cable (OPC-440), a regular CAT5e straight thru patch cable and a CAT5 in-line RJ-45 8-pin coupler can be used.

Radio Shack Parts:

7-Ft. (2.1m) Cat5e Computer Network Cable RS 278-2012
Snap-In Coupler RS 278-2037

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Send Questions and/or comments to: wy1u@arrl.net         Last Revised: 23-Feb-2019