TDOA Stations disappeared from map

johnjjohnj
in TDoA topics

Hi,

I noticed that from around 1300Z on 8 October 2025, the available TDOA stations and reference stations stopped appearing on the map which initiates when TDOA mode is selected. I tried again this morning and the map is blank. The radio buttons and other functions of the map work fine and I toggled the reference/TDOA stations radio buttons but none of the stations reappeared.

Looking back in my log, these symptoms appear similar to the problem on 28 August. I would be grateful if someone could take a look at the problem or advise how I can get the stations back.

many thanks,


John

Comments

  • jksjks

    What happens when you try to access the sampling and reference station lists directly from a browser?

    http://tdoa.kiwisdr.com/tdoa/files/kiwi.gps.json

    http://tdoa.kiwisdr.com/tdoa/refs.cjson

  • johnjjohnj

    Hi JKS, thank you for your reply.

    As of 1130Z on 10 October I can see and select the reference and sampling stations from the global chart. TDOA results timed out so it doesn't appear to be doing the calculations. I will try a few more and see if it was just those stations or a wider issue.

  • johnjjohnj

    Hi JKS,

    I subsequently tried a variety of stations and got some credible TDOA results back so I think the issue is fixed or at least resolved. I will try a few more as the day goes on and see if that remains the case.

    Thanks ever so much for your assistance, it is very much appreciated.

    all the best, John

  • jksjks
    edited October 10

    Hi John,

    Yesterday I found the kiwisdr.com web server, on which the public registration and TDoA services run, in a somewhat broken state. The CGI service, which responds to TDoA processing requests, was clogged up with TDoA processing tasks that were huge (in terms of memory use) and refusing to exit after the timeout period.

    I don't recall seeing this situation before. It's not supposed to happen. Anyway, restarting the web server cleared it. I'll keep an eye on it and see if the problem recurs. It likely explains the issue you were seeing.

  • G8JNJG8JNJ

    Hi John,

    I've not been having much luck with TDoA runs over the past few days.

    Every time I seem to get "Protocol Error" message. Although after a while the map showing the results does finally appear.

    In addition, half way though even short runs, I get the message that no receiver is available on stations that I've already determined to have vacant slots. Could the TDoA function "reserve" a receiver slot for a short period say < 2 mins, once a KiWi is selected for a run ? I think this would actually improve receiver availability for non TDoA connections, as folks running TDoA's keep on having to repeat the runs, before they can complete one with all the selected stations remaining available for the duration. The timer could maybe reset for another period, once an initial run has been completed, to permit another run.

    Just some thoughts.

    Regards,

    Martin

  • jksjks
    edited October 13

    I reworked the timeout values on the TDoA server so that you will get the correct "Timeout: excessive runtime" error message if the TDoA processing is taking more than 2.5 minutes (150 secs). The Kiwi user side code has a 200 sec timeout which produces the "protocol error" if it doesn't hear from the TDoA server within that time period. But this includes the sampling time, so it was being triggered early.

    If you're getting timeouts you might have sampling stations with poor signal reception or a signal with poor cross-correlation properties. It's not going to take more than two minutes for any valid TDoA solution to occur. That's just wasting precious time on the server that is also severely overworked by the proxy service.

  • G8JNJG8JNJ

    OK, thanks John.

    Regards,

    Martin

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