APRS TNC Setup - offline SARTopo

r70's Avatar


31 May, 2020 07:41 PM

I am trying to set up a TNC connection with a Kenwood TM-D710G. When I include the following lines in my sar.properties file... (as outlined here - https://help.caltopo.com/kb/objects/aprs-objects )


The command prompt window pops up and starts to run Java but then errors out very quickly and closes the command window. When these lines are not in my sar.properties file then offline sartopo runs fine. It's actually sarsoft.location.aprs.local.enabled=true that seems to cause java to crash.

I just downloaded Offline SARTopo and Java on 5/30/20 as per https://help.caltopo.com/kb/caltopo-desktop-formerly-offline/installing-and-running-the-caltopo-desktop-app-windows. so the versions should be the latest. I am running Win 10 Home. A crash log is attached.


  1. Support Staff 1 Posted by Ben Lantow on 01 Jun, 2020 02:54 PM

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    Hey Jim,
    We're looking into this. Thanks for kicking over the log file, helps a ton. Give us a day or two for debugging and one of us will reach out.


  2. 2 Posted by r70 on 01 Jun, 2020 11:59 PM

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    Sounds good. If I can do anythine else to help please let me know.

  3. Support Staff 3 Posted by Ben Lantow on 03 Jun, 2020 04:57 PM

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    We think this may be related to Java 14 specifically which was just released. If you download Java 13 instead (remove 14 completely), this should start working. We're going to figure out what the issue is and fix it but since Java 14 is so new, and so few users use APRS would you mind trying to use Java 13 instead?

    Here's a link to installers for 13: https://www.oracle.com/java/technologies/javase-jdk13-downloads.html


  4. 4 Posted by r70 on 03 Jun, 2020 05:00 PM

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    Hey Ben,

    Thanks for the quick response. I’m happy to try Java 13 in the next few days and will let you know.



  5. 5 Posted by r70 on 04 Jun, 2020 03:03 AM

    r70's Avatar

    Hi Ben,


    I was able to install Java 13 and now offline sartopo comes up ok with the added lines for TNC in sar.properties . I’ll test the TNC connection sometime over the next few days.


    Note – I still had to update the path variable to include the java bin directory.


    Thanks for your help!

  6. Support Staff 6 Posted by Ben Lantow on 04 Jun, 2020 01:05 PM

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    Thanks so much. We'll dig into this more.

    And yes Java in 13 and 14 no longer installs to the PATH for some reason. We're going to start packaging the entire release with Java for the future sometime in the next couple months.


  7. Ben Lantow closed this discussion on 04 Jun, 2020 01:05 PM.

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