Correct, the original timings were fit into a "window" vs. simple
scaling. Since the slowJT exe wouldn't run in WINE, I just ran a few
commands to decode K5DNL:
arecord -c 1 -r 12000 -f S16_LE capture.wav
sox capture.wav capture_tmp.wav speed 2.0
jt9 -9 -d 3 -S 300 capture_tmp.wav
0000 1 -26 0.1 2400. 1 VVV DE K5DNL JT9
jt9 is the standard executable decoder from WSJTX v1.9.1.
73 Eric NO3M
On 11/12/18 3:12 PM, N1BUG wrote:
Eric brings up a good point. Forget what I said the other day about
beaconing with a U3S to be received by SlowJT9. I believe that won't
work because the U3S uses the original JT9-2, -5, -10, -30 symbol
lengths which are different.
Probably (a guess) in the original, symbol lengths were chosen to
fill as much of the period as possible while leaving enough time at
the end for decoding. I would further guess there were specific
decoders for each submode, or one decoder whose parameters could be
modified for the current submode.
On 11/12/18 2:47 PM, Rik Strobbe wrote:
yes, a scale factor of 2 and 5 is used.
I hadn't any information about the old JT9-2 and JT9-5 modes and
those scale factors seemed the most straightforward to me and
make the conversion to JT9 easy.
73, Rik ON7YD - OR7T