[wsjt-devel] FT8 Extended Free Text QSO Experiment

[Jordan S. <jor...@gm...>]

Howdy y'all!

I had mentioned this free text idea a bit ago when Joe brought up the
"extra bits" available in FT8. Since then, I've been noodling on whether or
not a freeform QSO would even be enjoyable with such a low transmission
speed. The benefits, of course, being combining the enjoyment of a free
text QSO (ala PSK, RTTY, etc) with the sensitivity of the FT8 mode with
operation well under the noise floor. Well, the only way for me to really
figure out if it was feasible was to code up an experiment.

The basic idea is to take a freeform qso textarea and break it up into a
series of FT8 compatible transmissions. If following the standard protocol,
everything works as is, ala "CQ DX KN4CRD EM73" as one message. Anything
that falls outside of this is broken into the 13 character free text
messages. The messages are transmitted in sequence, with the operator able
to edit the next transmission of text while the current one is ongoing.

This doesn't actually use the "extra bits" that Joe had mentioned. But, I
could see those being useful for extending the protocol for synchronizing
which transmit cycle to use, or as a stop marker for when the transmission
is complete and the operator will be waiting for a response. Message
duplication could also be utilized to ensure delivery. Or maybe even a
final checksum message to ensure validity of the message.

Attached is a screenshot of the main window in an "extended qso mode". And,
here's a video of it in action:
https://widefido.wistia.com/medias/7bb1uq62ga

Now, the code involved for this is a little hacky, leveraging toggling the
Tx Even/First checkbox and other things of that nature since I don't know
the WSJT-X codebase all that well. But, I'd love to see if a few people
would be interested in checking out the patch and doing an on-air QSO with
me. And then, if there's interest, to clean this up into an actual feature.
Let me know!

Anyway. Cheers y'all! Loving WSJT-X and FT8. Hope to see you on the air!

Best,
Jordan
KN4CRD