You're assuming that the algorithms used in WSJT-X would be adaptable to
RTTY to give better performance than what is already out there. I don't
think there is any evidence of that being the case, given the very rigid
constraints that every single WSJT-X mode requires. The appeal of RTTY
for almost everyone (compared to FT8 or FT4) is its free form nature.
Just go read the current dialog on the CQ-Contesting reflector to see
what I mean. If you try to turn RTTY into a 2-tone version of FT8
neither user base will ever use it because it doesn't have the
advantages of either mode.
Secondly, WSJT-X is simply a very bad contest user interface. It was
designed for weak signal DXing and it does a very good job for that, but
it is terrible for contesting. Again, check out the CW-Contesting
reflector (you can just read the archives if you aren't subscribed) to
see more comments on that point ... most of which have been from me.
I really don't think you understand what you keep proposing here, but it
doesn't really matter because there is no way Joe Taylor is going to
mess with it since I'm sure he does.
Dave AB7E
On 1/15/2020 7:20 AM, Frank Kirschner wrote:
On Tue, Jan 14, 2020 at 11:32 PM David Gilbert
<xda...@cis-broadband.com <mailto:xda...@cis-broadband.com>> wrote:
What would that be? FT8/FT4 uses a better detection scheme than
RTTY precisely because of the constraints that FT8/FT4 require.
Those constraints are what allow the better decoding ... there is
no "magic" involved here.
No one suggested magic. The program has MFSK as one mode option. (It
has many modes, not just FT8.) RTTY uses BFSK, and BFSK is a subset
of MFSK. In order to discriminate which tone is being sent, there is
an algorithm the program uses. Some algorithms are better than others.
If you look at the various RTTY programs available, you will see a
considerable variation in error rate vs. S/N. DM780, for example,
requires an S5 signal to get reasonably good print, and around S9 for
100% print. Others are slightly better. My thought was that the
frequency discrimination algorithm in WSJT-X is better in the presence
of noise than most of the other programs available. (I've hear the
word, "bins" used, so I suspect that FFT is at the heart of the
discriminator.) Using this as the heart of a RTTY program might
provide an improvement in performance on RTTY in the presence of
noise. I understand that RTTY doesn't use or allow the redundancy and
error correction techniques found in FT8, so the performance will
never approach that of FT8. But it could be improved. Many years ago,
I used a T/U with tuned circuits using 88 mH toroids, and Kleinschmidt
teletype equipment, and could get very good print even when the signal
faded below my ability to hear it in the headphones. I haven't found a
single program currently available that approaches that.
I understand that there is finite time available for programmers. For
me, as a user, WSJT-X works splendidly, and short of printing out QSL
cards, putting stamps on them, and taking them to the post office, I
don't know what else it could do for my operating practice. Since
WSJT-X is now used in RTTY contests, it seems like it would be a
natural fit to add a RTTY window to the program. The UI is completely
different, but much simpler for RTTY. An alternative might be for
someone who already knows the code in WSJT-X to write a small external
program that is called when "RTTY" is selected as the mode in WSJT-X.
Since WSJT-X is used in RTTY contests, this would make it more
convenient. Is WSJT-X more of a test bed for experimenting with new
communications modes or a T/U program intended for daily and contest
use by hams? Of course, the developers make the choice as to the mix.
I was simply stating my preference as one ham among many.
73,
Frank
KF6E
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