SarTopo Offline & APRS

takeuchi's Avatar


03 May, 2018 07:46 PM

I see references to sartopo working with APRS, but nothing that really says where to start to make it work.

Very interested in getting sartopo to work especially where there is no internet infrastructure.


  1. Support Staff 1 Posted by matt on 04 May, 2018 09:35 PM

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    Edit the file and add the following:


    After that it will listen for APRS data (text out of a TNC, not KISS format) on attached serial ports. On a saved map, you need to do Add New -> Add Locator, type APRS. The interface is a little odd for APRS since it's designed to work with a number of different tools, but you need a separate locator group for each callsign (not counting -XX SSIDs), so it's easiest if you can use a single team callsign with different SSIDs for each member, inserting the operator callsign into the comments section of the packet if needed.

    Local APRS traffic that doesn't match an existing locator group should show up in a "callsign" folder on your map, to give you a sense of traffic that you're not tracking.

  2. 2 Posted by takeuchi on 05 May, 2018 02:00 AM

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    Thank you so much for the reply... I think this helps, but have a few questions...

    1. I don't see "Add Locator" maybe that's want I'm missing.... Is this a new feature an I'm down level?

    2. If I get a TNC to read the APRS signals, anything I need in the system between SarTopo and the serial port to interpret the signals?

    3. If I am in an urban area, any thing different to use this with the web version of SarTopo or it should work there too? Or should I be pointing to something like


  3. Support Staff 3 Posted by matt on 05 May, 2018 04:23 AM

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    1. For technical reasons, it's only available on saved maps.

    2. No, as long as the TNC is putting out text similar to what goes out over APRS-IS (ie not KISS, sorry, I'm not up on the exact terminology at the moment).

    3. pulls data from the APRS-IS network

  4. 4 Posted by takeuchi on 05 May, 2018 06:33 AM

    takeuchi's Avatar

    Thanks Matt!

    Found the feature and now working to better understand the APRS-IS technology.

  5. matt closed this discussion on 07 May, 2018 03:38 AM.

  6. takeuchi re-opened this discussion on 08 May, 2018 09:15 PM

  7. 5 Posted by takeuchi on 08 May, 2018 09:15 PM

    takeuchi's Avatar

    Does anyone have recommendations for a radio for SarTopo / APRS? I was about to get a Kenwood TM-D710GA, but realize it has a serial output - sounds like another point of failure going from a serial port to USB.... Curious if a Yaesu FTM400 with USB port would work just as well?

    Any thoughts on this?


  8. Support Staff 6 Posted by matt on 09 May, 2018 05:51 AM

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    I'm not familiar with that radio. I also don't have time to digest this entire thread, but if there isn't a way to stop the radio from adding line breaks in the middle of a position report, that's not something I see myself handling any time soon. The serial port code is shared with other uses such as FleetSync, and it's all based on carriage-return terminated lines.

  9. 7 Posted by takeuchi on 16 May, 2018 06:30 AM

    takeuchi's Avatar

    You said "No, as long as the TNC is putting out text similar to what goes out over APRS-IS (ie not KISS, sorry, I'm not up on the exact terminology at the moment)." Everything I'm seeing seems to indicate all the radios to computer interfaces use KISS.

    I'm worried about going for a Kenwood TM-DM710GA for this purpose, finding out that I can only use KISS and it won't work with SarTopo. Am I worried over nothing and people have use this combination successfully?


  10. Support Staff 8 Posted by matt on 16 May, 2018 04:31 PM

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    Most radios support KISS as a mode; it looks like the Kenwood also provides other output formats that SARTopo should be able to read, but I'm having trouble finding sample packet data online that I could plug into my program to verify.

  11. 9 Posted by takeuchi on 16 May, 2018 09:52 PM

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    Just borrowed a Kenwood D700 - I'll tinker with it and report my findings here.....

  12. 10 Posted by takeuchi on 27 May, 2018 06:21 PM

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    I ended up not having luck with the Kenwood TM-D700.

    Purchased a Kenwood TM-710GA and it works perfectly! One key difference I found is a field on the Kenwood software that read "PC Port" and "PC Output" - on the RT Systems software that reads "COM Port Output" that worked perfectly.

    One thing I noticed is to be careful not to go switching the serial cable too much. The PC side and the radio side can get to the point where they aren't talking well... If that happens, rebooting the server on the PC and cycling power on the radio seems to help.

    Thanks - this is now working great!

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