JT9: A New Digital Mode for MF and LF

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F4DTL
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JT9: A New Digital Mode for MF and LF

Message par F4DTL » 27 octobre 2012, 19:30

I invite you to try a new digital mode called JT9, designed especially for making amateur QSOs at MF and LF. JT9 uses the structured messages introduced in 2003 for the JT65 mode, now widely used for EME and for QRP operations at HF. JT9 can operate at signal levels as low as -27 dB (in a 2500 Hz reference bandwidth), with one-minute timed transmissions. It also offers slower transmissions of 2, 5, 10 and 30 minutes duration, and the slowest mode can decode signals as weak as -40 dB. With one-minute transmissions, submode JT9-1 has a total bandwidth of just 15.6 Hz -- less than one-tenth the bandwidth of a JT65A signal. The other submodes are narrower still: a JT9-30 signal occupies about 0.4 Hz total bandwidth.

Note that these JT9 sensitivity levels are comparable to or better than those of WSPR, which uses simpler messages and is not intended for making 2-way QSOs. JT9 has much higher throughput and reliability than QRSS CW, including DFCW modes.

JT9 is implemented in an experimental version of WSJT called WSJT-X. Some further details can be found at
http://www.physics.princeton.edu/pulsar" onclick="window.open(this.href);return false; ... _Guide.pdf ,
and an early version of WSJT-X can be downloaded from
http://physics.princeton.edu/pulsar/K1J" onclick="window.open(this.href);return false; ... 1r2695.exe .

Please note: WSJT-X is in an early development stage. A number of improvements and enhancements are already in the works, and others will surely be added. Your feedback will be much appreciated!

-- 73, Joe, K1JT

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Re: JT9: A New Digital Mode for MF and LF

Message par F4DTL » 27 octobre 2012, 19:42

Je vous invite à essayer un nouveau mode numérique appelé JT9, conçu spécialement pour les QSO amateurs de MF et LF. JT9 utilise les messages structurés et imaginés en 2003 pour le mode JT65, maintenant largement utilisée pour les EME et pour les opérations QRP HF. JT9 peut fonctionner à des niveaux de signaux aussi bas que -27 dB (dans une largeur de bande de référence 2500 Hz), avec une minute transmissions temporisées. Il offre également des transmissions plus lentes de 2, 5, 10 et 30 minutes chacun et que le mode le plus lent peut décoder les signaux aussi faibles que -40 dB. JT9-1 a une largeur de bande totale de seulement 15,6 Hz - inférieure à un dixième de la largeur de bande d'un signal de JT65A. Un signal JT9-30 occupe environ 0,4 Hz bande passante totale.

Notez que ces niveaux de sensibilité sont comparables ou supérieurs à ceux des WSPR, JT9 utilise des messages plus simples et n'est pas destiné à faire des QSO. JT9 a un débit beaucoup plus élevé et plus fiable que le QRSS CW, y compris les modes DFCW.

JT9 est implémenté dans une version expérimentale de WSJT appelé WSJT-X. Certains détails peuvent être trouvés à

http://www.physics.princeton.edu/pulsar ... _Guide.pdf

Une première version de WSJT-X peut être téléchargée à partir de
http://physics.princeton.edu/pulsar/K1J ... 1r2695.exe.

S'il vous plaît notez: WSJT-X est à un stade de développement précoce. Un certain nombre d'améliorations sont déjà en cours, et d'autres vont sûrement être ajoutées. Vos commentaires seront très appréciés!

- 73, Joe, K1JT

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Re: JT9: A New Digital Mode for MF and LF

Message par F4DTL » 28 octobre 2012, 02:58

Many thanks for all the early feedback on WSJT-X, both on- and off-list.

A number of users have reported that PTT is not being properly released when as transmission is finished. I have not yet found a computer that exhibits this problem... and needless to say, it did not arise for any of us who made the first on-the-air tests. For this reason, running this bug down has not been easy.

If you have experienced this problem, please try replacing the wsjtx.exe that you got with the download with one I have posted at
http://www.physics.princeton.edu/pulsar/K1JT/wsjtx.exe

Depending on the nature of the problem, this one might issue an error message when it fails to turn off the PTT successfully. Or it might solve your problem, as it did for W7IUV.

One important note went out to the first testers, but was not in my more open announcement. This early program version may not properly re-initialize all parameters when you change between JT9 submodes. To be sure, it's probably best to restart the program after changing modes. This will be fixed soon!

I see that despite these early teething problems, a number of QSOs are being made tonight with JT9. I look forward to hearing summaries of your experiences!

-- 73, Joe, K1JT

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Re: JT9: A New Digital Mode for MF and LF

Message par F4DTL » 29 octobre 2012, 20:53

To: Users of WSJT-X and the JT9 modes
From: Joe Taylor, K1JT

Version 0.2 of WSJT-X, built from revision #2702 in the SVN directory,
has been posted on the WSJT web site. The direct link for download is
http://www.physics.princeton.edu/pulsar ... 2r2702.exe

Changes since version 0.1, r2696 include the following:

1. Sample rate for audio output has been changed from 12000 to 48000 Hz.
Tx audio may now be generated at any frequency from 500 to 20000 Hz.

2. The Decoder now tries to decode all synchronizable signals in the
"green zone", that is, within "Tol" Hz of the selected QSO frequency.
(Before, by default it decoded only the signal producing the highest
"sync" value. Other signals could be decoded by manually setting the
QSO frequency and reducing Tol as needed.)

3. The user's selected QSO Frequency is now saved and restored on
program restart.

4. The problem with re-initialization after changing sub-modes has been
fixed.

5. The problem (for some users) of not releasing PTT after end of a
transmission has been fixed.

6. The program now writes a log of all decodes to a file wsjtx_rx.log in
the wsjtx directory.

A few additional comments about the first few days of JT9 usage:

Last evening I called CQ with JT9-1 on 160 meters and made three quick
QSOs. Only one of the QSOs was pre-arranged, so the word is getting
around. Best DX was DN07dg, some 2271 km from FN20qi. We were all
using low power. So I can say that JT9-1 works well on 160m, providing
about the same sensitivity as JT65A in about 1/10 the bandwidth. On
160m JT65A may have an advantage in conditions with deep fades, since
its FEC has significantly higher redundancy.

WE2XGR, WE3XGR, WG2XJM, and possibly others in NA have been making QSOs
and other tests on 500 kHz.

You may continue to expect further improvements and new WSJT-X program
releases in coming days and weeks. Please keep the bug reports and
requests for new features coming! They are much appreciated.

-- 73, Joe, K1JT


__._,_.___

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Re: JT9: A New Digital Mode for MF and LF

Message par F4DTL » 06 novembre 2012, 23:07

To: Users of WSJT-X
From: Joe Taylor, K1JT

I have been saying that there would be no new release of WSJT-X until
after my return from travel on November 12. However, I found some time
today to work on the program before my departure. The results are
important enough to warrant a new release today. Version 0.3 r2717 of
WSJT-X has therefore been posted at

http://physics.princeton.edu/pulsar/K1J ... 3r2717.exe

Changes from r2713 include the following:

1. A bug in the decoder that led to erratic behavior (failed decodes)
under certain conditions has been corrected. Decoding is now much more
reliable.

2. A valid algorithm is now used to calculate S/N values for received
JT9 signals.

3. The header format of recorded *.wav files has been corrected. These
files will now play correctly in Windows programs that expect the
standard header.

More work remains to be done... but I think you will find the behavior
WSJT-X v0.3 r2717 much more reliable than v0.2 r2713. I look forward to
receiving your reports!

Once again: I recommend primarily using submodes JT9-1 and JT9-2 until
further testing of the slower modes has been done.

-- 73, Joe, K1JT

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Re: JT9: A New Digital Mode for MF and LF

Message par F4DTL » 14 novembre 2012, 20:35

To: Users of WSJT-X
From: Joe Taylor, K1JT

The installation file for WSJT-X version 0.4, revision 2731 has been
posted at

http://physics.princeton.edu/pulsar/K1J ... 4r2731.exe

In this revision a number of known bugs have been fixed, and the JT9
decoder is significantly improved. Among other improvements, the
program is now much less fussy about timing issues.

My "To Do" list for WSJT-X is far from empty -- for example, many
user-convenience features are yet to be implemented. However, in its
present state WSJT-X performs well and will enable you to make QSOs at
signal levels down to those specified on the last page of the User's Guide:
http://physics.princeton.edu/pulsar/K1J ... _Guide.pdf

In some circumstances the present decoder will seem slow. Speed
enhancements are yet to come. In the meantime, you will find it best to
set "Tol" (the frequency tolerance parameter) to a value only a few
times the width of the desired JT9 signal.

I have now made many QSOs with JT9-1 on 160 m, often with inaudible
signals. I look forward to working you on that band soon! I also hope
to have good receiving systems soon for 137 and 472/500 kHz: maybe we
can work cross-band? A number of us have been coordinating our activity
on the K3UK Sked Page: go to
http://www.obriensweb.com/sked/ and then click on "digitalradio" at the
upper right.

As always, your feedback on WSJT-X will be greatly appreciated! I'll do
my best to fix reported bugs quickly. During this testing period,
please remember to run the program with "Save All" checked, and send me
examples of *.wav files on which the decoder behaves poorly.

-- 73, Joe, K1JT

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Re: JT9: A New Digital Mode for MF and LF

Message par F4DTL » 16 novembre 2012, 22:46

To: Users of WSJT-X
From: Joe Taylor, K1JT

A new revision of WSJT-X has been posted. As usual, a link to it
appears on the WSJT web site:

http://physics.princeton.edu/pulsar/K1JT/wsjt.html

The following is a direct link to the installation file:

http://physics.princeton.edu/pulsar/K1J ... 4r2746.exe

Changes from v0.4 r2731 include the following:

1. Valid signal reports are now generated by double-clicking on a
callsign in the decoded text window.

2. Consecutive spaces in a Tx message are now collapsed into a single space.

3. Decoding speed is much improved, especially when strong (possibly
non-JT9) signals are present and "Tol" is set to a relatively large value.

4. Scaling of the "JT9 Sync" plot (red curve) is more reasonable.

5. Layout of widgets on the main window has been improved.

6. Several minor bug fixes.

As always, your feedback on the new revision will be greatly appreciated!

-- 73, Joe, K1JT

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Re: JT9: A New Digital Mode for MF and LF

Message par F4DTL » 28 novembre 2012, 18:19

To: Users of WSJT-X
From: Joe Taylor, K1JT

A new revision of the experimental program WSJT-X has been posted. As
usual, a link to it appears on the WSJT web site:

http://physics.princeton.edu/pulsar/K1JT/wsjt.html" onclick="window.open(this.href);return false;

The following is a direct link to the installation file:

http://physics.princeton.edu/pulsar/K1J" onclick="window.open(this.href);return false; ... 5r2783.exe

This revision has an unusually large number of changes relative to the
previous release, v0.4 r2746. These changes include:

1. PTT control via COM ports COM10 and higher is enabled.

2. Improved decoder performance: higher speed as well as better chances
of success. Moderate amounts of frequency drift are detected and
compensated. Computed S/N values are more reliable. Time offsets from
-2.5 to +5 s are now supported, which makes JT9 usable for EME. (EME
tests on 144 MHz have been successful, and performance on that
propagation mode appears to be good.)

3. Tx Frequency now tracks the selected QSO Frequency (unless you hold
down the CTRL key when setting QSO Frequency via mouse-clicks or the
F11/F12 keys).

4. Decoded text containing "CQ " is highlighted with green background;
text including "MyCall" is highlighted in red.

5. In previous versions, signal reports were required to be in the range
-30 to -01 dB. In v0.5 r2782 the range has been extended to -50 to +49
dB. There is backward compatibility for the range -30 to -01, but
reports in the range -50 to -31 and 0 to +49 will NOT be decoded
correctly by previous program versions. It is important to upgrade!

6. Items "Save Synced" and "Save Decoded" are now implemented.

7. UTC Date, JT9 submode, and a parameter related to the decoding
procedure are now included in file wsjtx_rx.log.

8. Editing of Tx messages (in any of the six Tx message boxes) is
complete when you hit "Tab" or "Return". The message is then parsed and
converted to the form in which it will be displayed if decoding is
successful. Free-text messages are trimmed to 13 characters and
highlighted with a pink background.

9. The most recent transmitted message is displayed in the right-most
label on the status bar. This can be useful if you have lost track of
where you were in a QSO.

10. By default, the program now starts with Monitor ON. An option on
the Setup menu allows you to select "Monitor OFF at startup".

11. Better scaling is provided for the red "JT9 Sync" curve. Note that
JT9 signals in the active sub-mode should appear in this plot as a bump
of width equal to the total signal bandwidth, with a narrow and slightly
higher bump at the left edge. The narrow bump is the frequency of the
Sync tone, which is defined as the nominal frequency of the JT9 signal.

12. Basic QSO information is now written to file wsjt.log when you click
the "Log QSO" button.

13. The WSJT-X User's Guide has been updated.

14. Other known bugs have been fixed. There will probably be new ones!
When you find one, or if you know of any old ones that have NOT been
fixed, please send me email.

Summary of Present Status
----------------------------------------------------------------------
I believe that WSJT-X is now a stable and very usable program. Many
thousands of QSOs have been made with JT9-1, mostly at HF -- I have made
nearly 100, myself. Also a number of QSOs have also been completed at
MF, and successful tests have been made on 2m EME, etc. A number of
QSOs have also been made with JT9-2.

As far as I know the slower modes (JT9-5, JT9-10, and JT9-30) also work
correctly. (Certainly they do in my laboratory test setup.) Most
people will find these modes too slow for "everyday" use, and they
require high frequency stability. It remains to be seen whether they
will be widely used.

An alternative approach to obtaining improved sensitivity would be to
give the decoder an ability to average over several successive
transmissions. For example, the average of five JT9-1 transmissions
could reach a decoding threshold around -32 dB, only 2 dB worse than a
single JT9-5 transmission. Because of QSB, the shorter transmissions
may actually succeed in less total time. Stability requirements would
be those of JT9-1, much less stringent than those of JT9-5.

Program development is not finished, by any means. I will be grateful
for your feedback on performance issues, as well as your "wish-list" of
features to be added. As always, example recordings of files that you
think should have decoded, but did not, will be much appreciated.

I hope to find time for more work on WSJT-X soon. Later this week,
however, my radio time will be focused primarily on the ARRL
International EME Contest.

With best wishes,

-- 73, Joe, K1JT

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Re: JT9: A New Digital Mode for MF and LF

Message par F4DTL » 29 novembre 2012, 16:53

To: Users of WSJT-X
From: Joe Taylor, K1JT

Revision 2786 of the experimental program WSJT-X has been posted. As
usual, a link to it appears on the WSJT web site:

http://physics.princeton.edu/pulsar/K1JT/wsjt.html

The following is a direct link to the installation file:

http://physics.princeton.edu/pulsar/K1J ... 5r2786.exe

Changes from yesterday's r2783 are minor, but may be important to you.

1. In r2783, the companion program jt9.exe (started automatically when
you start WSJT-X) was a CPU hog for no good reason. This was an
oversight on my part, and the bug has been corrected.

2. The program should now run correctly if installed in a directory
whose name contains embedded spaces. (Under Vista and Win7, however,
it's still not a good idea to install WSJT-X into
C:\Program Files, because of restricted write permissions there.)

3. In r2783 and earlier, stopping a transmission by toggling to "Auto
OFF" would terminate Tx audio and release PTT almost simultaneously,
possibly hot-switching your T/R relay(s). This has been corrected so
that proper sequencing takes place.

-- 73, Joe, K1JT

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Re: JT9: A New Digital Mode for MF and LF

Message par F4DTL » 30 novembre 2012, 17:21

To: Users of WSJT-X
From: Joe Taylor, K1JT

Revision 2788 of the experimental program WSJT-X has been posted. As
usual, a link to it appears on the WSJT web site:

http://physics.princeton.edu/pulsar/K1JT/wsjt.html

The following is a direct link to the installation file:

http://physics.princeton.edu/pulsar/K1J" onclick="window.open(this.href);return false; ... 5r2788.exe

I have posted a ChangeLog of WSJT-X program revisions at

http://physics.princeton.edu/pulsar/K1J" onclick="window.open(this.href);return false; ... ngelog.txt

Henceforth you should check the ChangeLog for information on what has
been changed in new revisions.

-- 73, Joe, K1JT

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