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Today's v1.694 update is hopefully a working version of the failed v1.691,692 release of a few days ago.
See the first post of the "v1.694" thread below for the CHANGE_LOG notes.
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v1.284: "disable recent changes" admin option, new SSTV extension

edited May 2019 in KiwiSDR Discussion
v1.284 has a new admin option switch on the "config" tab, at the bottom right of the page, called "Disable recent changes?". If you set it to "Yes" then changes in the current release that are somewhat risky will be bypassed (a restart will be required when the option is changed). In the v1.284 release this means the Firefox audio watchdog workaround and the task scheduler priority changes for the new SSTV extension will be disabled.

The new SSTV extension is a very preliminary alpha release. It is mostly intended to facilitate development since there is essentially no live SSTV reception on our own Kiwis in NZ. Use the "Test image" button to decode a stored test pattern (deliberately slanted to test the alignment code)

There are many known problems and essentially no user interface features. Please do not send us your bugs and suggestions for improvements until a more complete version is released.

The SSTV decoder algorithm is very FFT-intensive and has a large impact on the realtime response of the system. It seems possible to run one SSTV decoder, one WSPR decoder, GPS and some additional regular connections. But anything more than that is problematic (e.g. using it on a Kiwi with multiple WSPR auto-run tasks). So please be careful on which public Kiwis you use the SSTV extension.




  • Hi John,

    The SSTV decoder works pretty well.

    Oona has some interesting stuff on her webpages, I had posted a link to her split band descrambler on another forum earlier this week.


    Martin - G8JNJ
  • jksjks
    edited May 2019
    From today's v1.285 CHANGE_LOG file. I forgot to mention that the SSTV manual slant adjustment is useful in cases where the automatic slant adjustment fails.
    v1.285  May 6, 2019
        The "disable recent changes" switch is now on the update tab of the admin page.
        SSTV extension:
            Display reception SNR.
            Improved realtime behavior during times of low SNR.
                (was doing too much extra computation causing undesirable side-effects)
            Fixed a bunch of buffer overflow/leakage problems.
            Added manual slant/offset correction:
                Click two points in the image that correspond to where you think the left edge is located.
                Sometimes this appears in the image as a black vertical "sync stripe".
                The two points define a line whose angle is used to correct the slant of the image.
                The image left edge is also set to this line position after the slant is corrected.
                The clicked points do not have to be at the extreme top and bottom of the image.
                Click anywhere along the vertical axis to define the line. Only the accuracy of the
                angle and horizontal position is important.
                Currently you can only adjust the most recently received image if multiple images
                are displayed (the image marked by the yellow triangle is the latest received)
                The slant is properly corrected, but many times the left edge is not. Worse, the
                color planes become separated. This is being worked on.
  • I think a 'flesh tone' detector is required on the SSTV extension with an 'auto' blanking function - some very dubious pictures being transmitted on 14MHz mostly from Russian amateurs.


    Martin - G8JNJ
  • just sitting on 14.230
  • v1.286  May 8, 2019
        Sig gen extension now requires admin password (local network exemption applies).
        SSTV extension:
            Fixed left-edge image offset after manual slant correction.
            Show mode of each received image.
            Added band select menu.
  • Keep up the good work!!

    Jari OH6BG
  • Auto save picture option after 3 decodes like IBP scanner.
  • Read first post please. I already have a laundry list a mile long including what you suggest.
  • Hi John,

    I have been playing with the SSTV extension which is a useful new addition and generally works very well.

    I find that the majority of SSTV traffic (or at least the most active frequency that can be heard most of the time) tends to be 14230KHz. Note that this is the suppressed carrier (dial) frequency

    On that frequency the best filter bandwidth settings seem to be with the filter LF cutoff at frequency 700Hz and the HF cutoff at 2000Hz.

    This gives some margin for the signals that are slightly off frequency, or who are using wider frequency shifts, and these settings may be useful for the SSTV frequency tab you have just added to the extension.

    A manual start or reset button to force clear the decoder and get it to listen for tones would be useful, but only if / when you get around to it.


    Martin - G8JNJ
  • jksjks
    edited May 2019
    Yes, a start/stop/reset is next on my UI list.

    I've been working on getting the Robot color modes to work because I've seen R24 and R36 modes being used, especially in the EU. And the existing code doesn't handle them properly.
  • v1.288  May 11, 2019
        UI changes for devices with small screens: (phones or tablets)
            Control panel defaults to "Off" option tab making it smaller.
            Top bar (Kiwi information) is hidden but label area remains visible.
            Purple "readme" panel is always closed even on first-time site visit.
        SSTV extension:
            Robot modes R72 and R12BW working. R24, R36 and other B/W modes still need work.
            Band menu now has optimized passband for 1200-2300 Hz SSTV signal.
            Added reset button.
  • The UI changes are a game changer....
  • v1.289  May 13, 2019
        Save/restore last squelch value set.
        SSTV extension:
            New modes now working: R24, R36, W2120, W2180, PD50, PD90
            Untested modes: M3, M4
            "auto adjust" checkbox and associated "undo adjust" / "auto adjust" button.
                Allows you to undo a faulty auto image adjust or disable entirely.
            Added help button info.
            Use URL containing e.g. "&ext=sstv,14" to select 14230 band menu entry.
                Other options "test", "noadj".
  • edited May 2019
    On a slightly related note I left two SSTV extensions going here on two Kiwi's with similar antennas, different feeds, PSU etc. while trying to get that last bit of S/N in this "Mainly N" location.
    The resulting images were good for comparing reception and although I've only so far been able to see things on 20m it's a faster (unattended) feedback loop than other methods. It's also good neck exercise try to work out what exactly I'm looking at on some images.
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