Pre-emptible extension in background

I was trying out background decoding for FT8 the other day on one of my Kiwis, selecting "yes" for pre-emptible. That seemed to work, though I was hoping that FT8 decoding would resume once that slot was unoccupied by a visitor. So if I understand correctly, pre-emptible is a one time event that will free up a channel for a user if it's needed, but will not return to the decoding afterwards.


  • No, it should return to decoding afterwards. There will be a slight delay before it restarts (I forget how long).

  • Ok that is good to know. I did some more testing on another Kiwi in 4 channel mode, loaded up with FT8 decoding, and it seemed to work just like that, returning to decoding once the user let go. I need to do more testing on the other one that was in 8 channel mode, with seven of the eight slots normally occupied a wsprdaemon PC. I'll do some more experimenting with that one.

  • Remember that 8 channel mode is a little weird because things that don't use the waterfall, like autorun WSPR/FTn, try and always leave rx0/rx1 free for user connections. So although it will restart after preemption it may not behave exactly as you might expect.

  • Ahhh, it now all makes sense, since the only open slot on the Kiwi in 8 channel mode was RX1, so assigning the background task to that slot probably is what made it avoid starting up again. Thanks for the rapid feedback to all my queries!

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