MF WSPR

NU6FNU6F
edited October 19 in WSPR, wsprdaemon, kiwirecorder

I am asking to see if anyone is having issues with monitoring WSPR on 630m with their Kiwi?

The WSPR extension runs fine on other bands....but my main interest on this kiwi install in the Azores is for 630m.

I have been using the Kiwi to feed my instance of WSJTX here at my home QTH on the island.

But when I dedicated one channel to run wspr on 630m I see no decodes except my own 20p watts signal 2km away.

But using another channels audio to feed my instance of WSJTX running on my PC here at hone

I see all the WSPR decodes?

Any ideas what's going on?

Ron

CU8/NU6F

Flores island Azores, Pt

Comments

  • jksjks
    edited October 19

    Maybe because of a difference of offset frequencies.

    By default the Kiwi WSPR decoder is configured to use a 750 Hz offset. WSJT-X uses 1500 Hz. So if you have the Kiwi WSPR running using its dial frequency of 474.95, but then tune the Kiwi to a dial frequency of 474.2 so that WSJT-X decodes (474.2 + 1.5 = 475.7, the 630m passband center), the Kiwi WSPR passband will no longer be centered on 750 Hz. So no decodes.

    You can change the Kiwi WSPR offset frequency to 1500 Hz in the admin, extensions, WSPR section. I couldn't find a way to set the rx offset of WSJT-X to 750 Hz which would be the other option.

  • jksjks
    edited October 19

    But also, the decoder in WSJT-X is superior to the one in the Kiwi. Why? Two reasons. The Kiwi decoder was derived from a version of WSJT a long time ago. There have been many improvements to WSJT-X since. And the computing power of your average pc/laptop running WSJT-X is huge compared to the Beagle of the Kiwi. That's why for example WSJT-X supports spectral subtraction and other algorithms in its "deep seek" mode. Your pc has the horsepower to pull that off.

    The Kiwi WSPR decoder was the first extension developed back in 2016 as an example of the extensions concept. It's not meant as a competitor to WSJT-X. I've said this on many, many occasions. Same for the FT8 decoder etc.

  • jksjks
    edited October 19

    I was able to camp onto a channel of your Kiwi that must be piped to WSJT-X given the dial frequency of 474.2 shown in the camp display (there were no free channels for me to connect directly). WSJT-X running here on that camped audio found G4SDG at 21:02, 475.780 at a weak -23 dB. But the Kiwi WSPR autorun you have running on another channel didn't increment its decode counter at that time slot. So it missed it. But it is seeing your WSPR TXs as you mentioned earlier. So its offset must be okay.

    So I think this is just a case of the Kiwi decoder missing very weak signals.

  • jksjks
    edited October 19

    Okay, but now G4SDG has faded up to -18 dB according to WSJT-X. And the Kiwi WSPR autorun decode count went from 12 to 13 during that time slot. So it worked at that signal strength. I think this confirms what's going on.

    NU6F
  • NU6FNU6F

    Ok,thanks...well guess it's just a limitation of the internal wsjtx program..I can route the receive audio to my wsjtx here at my tx location and pick up the EU and USA stations down to -30db SNR

    Ron

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