Cambridgeshire Repeater Group

Hi all,

I've been playing with DPRS recently and think I've now got to the stage where I can comfortably share how to use it.

RADIO RX
You use the serial data cable for DPRS, schematic of it is here: http://www.epaares.org/dstar/_derived/icom_cables.htm_txt_image003.gif. I've found that to get the correct DPRS string out of the 2820 (and I guess the E91) you need to have the radio set to GPS mode and not GPS-A. This is counter intuitive as you need to have the radio set to GPS-A on the 2820 to send the DPRS string from the radio using it's own GPS! The reason is so the line is of the format $$CRCxxxx,xxxxx>APRS:<rest of packet>. Without the $$CRC it is not recognized as a valid string and passed to via DPRS Interface (see below) to UI-View.

RADIO TX (2820 only)
For GPS mode (if you own an E91) see the post below. If you have a 2820 you need to use the following UNPROTO ADDRESS for the 2820: API282,DSTAR* found under the GPS-A SET MODE menu. This makes sure the traffic is routed via DPRS Interface to UI-View. Also make sure in the setting DV GPS > GPS SENTENCE that RMC and GGA are ON.

SOFTWARE
To convert the DPRS string to APRS for UI-View you need DPRS Interface, it is available here: http://www.aprs-is.net/DPRSInterface.aspx and UI-View here: http://www.ui-view.org/

CONFIGURATION
Configure DPRS Interface for the radio you are using. The 2820 uses a baud rate of 9600 and the E91 38400, only your callsign is needed too. I have AutoStart ticked. After this is done click on View and tick Direct, this will show on the screen any GPS data from the radio. DPRS Interface provides 3 ports for other programs to connect to it. One is for UI-View.

Ui-View connects to DPRS Interface as an APRS-IS (like it's an internet server). Open UI-View and then goto Setup > APRS Server Setup. Click on a server in the list and press the INSERT key on your keyboard, this will allow you to enter a new server. Type in 127.0.0.1:14551 then click on OK. Goto menu Action > Connect To APRS Server. You should get a green rectangle at the top of your map, if you get an error check DPRS Interface is running and the IP and port number you entered are correct.

TROUBLESHOOTING
After this you should then start to see DPRS stations on your UI-View map. As you have Direct ticked on DPRS Interface you should also get the RAW DPRS strings appear there, if info is there but not in UI-View check the GPS strings you see start with $$CRC, if not check you have your radio set to GPS and the other station is transmitting in GPS-A mode.

If you are still having problems please let me know.

Hi all,

A major update!
After chatting with Pete AE5PL who pretty much invented DPRS he's explained to me that there is a way for normal GPS mode, not just A-GPS (as I've advised) to work with D-PRS and thus UI-View, this included E91 radios, assuming you have a GPS connected to it. Pete mentioned this to me before but I didn't quite get what he was meaning!!!

Anyway the problem is that in GPS only mode there is no checksum to know the station callsign was correctly decoded and as such unless a checksum is received by D-PRS Interface it doesn't pass callsign/position info down to UI-View.

C1 Message Calculation
We need to calculate your checksum, known as C1. Goto this page: http://www.aprs-is.net/DPRSCalc.aspx enter your callsign and choose the icon you wish to have shown with your callsign, enter a short GPS Message if you like. Now take the string which has appeared in the "Input into TX Message C1" and copy it into your GPS Message on your radio. For the 2820 it's MENU > DV GPS > GPS MESSAGE (manual page 124), on the E91 it's MENU > MESSAGE/POSITION > TX MESSAGE (manual page 59) and on the E92 it's MENU > MESSAGE/POSITION > GPS.

My C1 message is: 'BI GAV DPRS 2820*6A' (note there are 2 spaces after BI).

What This Means
What this means is we can all run in GPS only mode! Not A-GPS mode as I originally advised. This allows users of the 2820 to use the inbuilt POSI screen to see where stations are and more importantly it allows users of E91 handhelds which don't have A-GPS to show up on UI-View!


Let me know if you have any comments.

Curious that they don't appear to provide one that is particularly suitable for pedestrian mobile operation, despite including several more specialized modes of transport. "Jogger" is the nearest, but isn't exactly the image I want to project!

I covered in the first post how to get A-GPS beacons to appear in UI-View. I covered in the second post on how to use normal GPS beacons to do the same but I've been having problems getting UI-View to beacon view D-PRS Interface and out on your D-Star radio, this has now been solved.

RADIO
No matter which radio you have you need to have GPS off in the settings menu. The reason for this is that you need to give the serial part of the data stream over to the external data. This shouldn't present a problem as you will be at home.

SOFTWARE
To convert the DPRS string to APRS for UI-View you need D-PRS Interface, a new version has just been released with new features, it is available here: http://www.aprs-is.net/dstartnc2.htm and UI-View here: http://www.ui-view.org/ your version on UI-View needs to be registered.

UI-VIEW
UI-View connects to D-PRS Interface via the server address 127.0.0.1:14551 we created in the first post. This time though you need to make sure you have ticked 'APRS Server Log On Required' and you enter your Validation Number in the box provided, this is the 5 digit number which comes with your registration code here: http://www.apritch.myby.co.uk/uiv32.htm Goto menu Action > Connect To APRS Server, Click Yes to Logon When Connected. You should get a green rectangle at the top of your map.

D-PRS Interface
D-PRS Interface has some new features, one of which is the Server Status page. If you have the new version of D-PRS Interface running and have connected to it via UI-View then in D-PRS Interface goto TOOLS > SERVER STATUS and scroll to the bottom of the page. There you will see a table called 'Inbound Connections', the first line should start IGate, <callsign>, Yes, javAPRSIGate 2.3b05... under that you sould get 14551, 127.0.0.1:xxxx, <callsign>, Yes, UI‑View32 V2.03 if Ui-View is connected. If not connect UI-View and refresh the Server Status page by pressing F5. The callsign and Yes are important, if they are not there check your UI-View APRS Server Setup and expecially your Validation Number. Without them you will not transmit only receive.

TRANSMITTING
When you transmit from UI-View, no text or info is shown in the D-PRS Interface. The radio should TX though and this should be enough sign that it works. Remember D-PRS Interface acts like an APRS-IS and as such will only allow the same beacon to be sent once every 30 seconds, remember this when testing.

The only draw back to using UI-View to beacon your location is no proper GPS coordinates are sent so will not appear on other radios.

I have it running here on my 2820 with an MFJ TNC2 on 144.800 and D-Star DPRS running on GB7PI and it works fine. Just need to find out ho to digi both together.

Questions/Comments?

To gate between the DPRS and the APRS, why not run Xastir instead of UI-View, it allows multi-port operation. There is also another way of doing it with one copy per port running, and then another copy running to act as the "gateway", sending data between the three as UDP data internally. More details are on the 'net if you look for "running multiple copies of xastir on one machine".

Of course, it means running under a nice flavour of Linux to do it properly.

Rob.

D-PRS Interface limits what type of trafic is sent over the gateway, limited to the callsign of the user. It will allow any software which can connect to an IGATE to connect but with the same limitations.

Hi Gavin i have been reading your posts over the last week or so and have setup my radio and dprs interface and ui-veiw and all is working ok between all the fixed stations on the wirral.But can you tell me how i can track a mobile station? what should the setting be set to in the mobile station ,ie gps on or off .I am sure the gps needs to be turned on in the mobile.
i have disconnected my radio from the pc turned on the gps and i was hopping the fixed stations would see me on ui-veiw but they carnt.Is there a way for home base stations to see mobile stations whilst running ui-veiw. if so can you please help me with the setup Thanks chris m1eev....

Hi Chris.

Yeah this is possible, look at the section called "C1 Message Calculation" in the second post by me. When using GPS only mode on the 2820 (or E92) add the C1 checksum to the GPS message character for character and this will allow mobile stations to display your location and also anyone using DPRS Interface/Ui-View. If you just stick to GPS-A then you need to make sure your UNPROTO ADDRESS is API282,DSTAR* but as you know Icom radios won't display GPS-A beacons on the screen.

Remember the GPS only works on DV mode and the 2820 doesn't do analogue APRS, just incase that's what you were asking

Let me know if this helps.

Ok Gavin i have run the c1 message calc and added the c1 checksum to gps message .
It looks like this. MV 2820*35 And the gps is turned on in gps mode not gpsa.
Does this know mean that fixed stations runing ui-view with dprs and 2820 radios with there gps turned off will see me on the map. thanks chris.....

Hi Chris,

I've checked and the message (C1) looks fine to me It should now work.

Let me know how you get on...

Thanks Gavin i have just tryed this with John G7LLQ he has his connected to his pc with gps off and i have my radio with gps on and he is tracking me ... Thanks for all your help. chris and all the d-star users on the wirral/////

Hello Guys, that's my 1-st post on this forum - don't kill if it's silly

I was just wondering about DPRS...

I understand all above, but that means some IGate with D-Star enabled radio must be available in area to receive beacons and also software is needed to convert data...

In most of locations D-Star repeaters are receiving our signal any way. Is it any chance to send DPRS beacons via D-Star repeaters avoiding use of local IGates??

Hi Martin,

The question isn't silly. In the world of D-PRS there aren't really entities known as IGates. In APRS you could put a simplex radio on with a TNC and UI-View with your activation code which would allow you to gate APRS traffic around the world. In the world of D-PRS there isn't such an entity. D-PRS is an add-on to GPS positioning which just uses the slow speed data channel add-on to main use of DV mode, voice. So at the moment there is no D-PRS equivalent to IGates per say...

The way it works in D-Star is you require a repeater (regenerative node) with a gateway. On the gateway PC you run a piece of software called javAPRSSrvr which gates D-PRS 'packets' configured as per this guide to the APRS network. Another piece of software called DStarMon uses GPS info to plot your location against a last heard list such as on findu.com.

Hope this helps.

Which means D-Star repeaters are capable to plot your position on map - OK.

How you recon: are admins placing this piece of software to gateway computers as a standard or it is not usual procedure??

What about radio config - is it worth setting DPRS and keep D-Star network busy or better is just install TNC with GPS and use standard frequency(144.800MHz)?? Found bit of information on one of the US web sites ( http://www.k6mdd.org/ ) regarding generated "traffic" in D-Star when using DPRS and worndering if this option is acceptable or not...

Hi Martin,

Yeah the software is installed as an option onto the gateway, it's non-icom. As for DPRS remember it's a bolt on to a bolt on so it's not advisable to be sending lots of DPRS beacons on a repeater which is primarily used for voice traffic. If you set your radio to beacon every 10 or 15 mins that should be OK. For now APRS on 144.800 is the best place to be doing position based radio stuff. That said I have been thinking for a while about getting agreement and allocation of a frequency for DPRS only traffic but not gone forward with it yet.