Loran-C display truncated [fixed in v1.152]

In my browser (Firefox), the Loran-C display gets truncated beyond GRI values over about 6900. I don't know if this is a Firefox issue or a Kiwi issue.

Regards

Mauritz / SM2BYC
Screenshot-2017-11-26 KiwiSDR.png
1751 x 1091 - 2M

Comments

  • jksjks
    Accepted Answer
    I'll have a fix for this in the next release.

  • Thanks, looks good. Now I just have to figure out how to identify the master in the Chayka chains.

    Regards

    Mauritz / SM2BYC


    Screenshot-2017-12-6 KiwiSDR.png
    1751 x 1091 - 2M
  • jksjks
    edited December 6
    This reference http://jproc.ca/hyperbolic/loran_c_sigchar.html says carrier phase coding can be used to determine the master, given that the Chayka master doesn't transmit a ninth pulse (or they all transmit 9 -- I can't remember). But the problem is that there is not enough time resolution in the audio IQ data at 12 kHz bandwidth to detect carrier phase. This same problem prevents any real nav solution since you can't detect the "third zero-crossing" of a pulse with any accuracy either. A different DDC configuration in the FPGA is needed to get more time resolution (bandwidth). Some people would also like this so they can run larger IQ bandwidth to external applications (like other SDR IQ processing programs).

  • OK. I thought that the ninth pulse was the only way to indicate master transmitter. However in the chayka chains there are several transmitters with nine pulses. So probably they also use phase coding to identify the master. Despite the limited timing resolution of Kiwisdr, I have seen double-pulses on Chayka/Loran-C transmitters indicating multi-path propagation. Hyperbolic navigation seems to have quite a few interesting challenges.

    Regards

    Mauritz / SM2BYC
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