To: Users of WSJT on 6 meters
Subject: WSJT Beta Version 3.6.3
Date: Sunday, 23 Mar 2003
From: Joe Taylor, K1JT ([email protected])
WSJT Beta Version 3.6.4
-----------------------
The previous version had the threshold set very low for all mouse-picked
decoding attempts in JT6M mode. This was useful to me for testing, but
produced excessive gibberish. Version 3.6.4 has a reasonable threshold and
produces much cleaner output. In addition, the message averaging algorithm
has been improved. I find that I seldom need to use either "Freeze" or
"FixAve" now. These buttons are still present in version 3.6.4, but unless
I hear that people are finding them useful I may remove them soon.
An option has been added to the Setup menu so that you can determine
whether you want the "Tx Stop" button to kick you out of Auto Mode, or
not. The default is not to do so.
***IMPORTANT***
If you can make WSJT v3.6.4 crash in normal operation, please let me know
(and tell me how). Also let me know if you find anything that does not
work as intended. I believe the present code behaves well and is nearly
ready to be upgraded from "Beta" status to a full release.
WSJT Beta Version 3.6.3
-----------------------
Version 3.6.3 has a number of small improvements, many of them not
immediately visible. Several bugs have been exterminated. The JT6M
decoder works better and is more sensitive. JT6M now has a "FixAve"
checkbox; when this is checked, average messages will be sought only
at the lengths of the automatically generated messages.
WSJT Beta Version 3.6.2
-----------------------
Version 3.6.2 corrects a problem that on a few machines caused a
fatal error that could only be corrected by deleting the initialization
file, WSJT361.INI.
WSJT Beta Version 3.6.1
-----------------------
Version 3.6.1 corrects a problem that caused an immediate termination
on program startup on some users' machines (typically older ones). If
you need this upgrade, you need it bad!
It also fixes a minor bug that could cause a divide-by-zero error if
you clicked on the plot area when no data was available to analyze.
WSJT Beta Version 3.6.0
-----------------------
The JT6M mode is only a week old, but many hundreds of QSOs have been
made with it all over the world. Thie mode is expressly designed for
meteor scatter on 6 meters, but it may be useful with some other
propagation modes as well. It has characteristics that place it about
midway between FSK441 and JT44 in both speed and sensitivity. A
second beta release of WSJT with JT6M, Version 3.6.0, is now available
for downloading at
http://pulsar.princeton.edu/~joe/K1JT/UPD360.EXE
The download file is about 0.75 MB in length.
Comparison of Versions 3.6.0 and 3.5.1
--------------------------------------
1. Version 3.6.0 has a better and faster decoder for JT6M. Further
improvements in this area are still to come.
2. Several bugs that could cause crashes in V3.5.1 have been fixed.
Version 3.6.0 appears to be quite stable (at least on my own
computers).
3. Some buttons have been moved from their familiar positions.
4. Gadgets that Microsoft calls "Up-Down Controls" have replaced the
+/- buttons used for various decoding parameters.
5. You can now drag the mouse pointer across any portion of the large
plot area to cause decoding of that portion of a recorded file. This
works in both FSK441 and JT6M mode. The area you selected is marked
when the plot is refreshed.
6. A yellow curve now appears above the green curve in JT6M mode. The
yellow line represents measured power received at the sync-tone
frequency and in the sync-tone intervals.
I haven't yet written up any detailed instructions for the JT6M mode.
However, if you are an experienced WSJT user you probably won't need
any. Here are a few things it will be helpful to know about JT6M.
1. Like JT44, JT6M uses 44-tone FSK with a "sync tone" and 43 possible
data tones -- one for each character in the supported alphanumeric
set. The sync tone is at 1076.66 Hz, and the 43 other possible tones
are spaced at 21.53 HZ intervals up to 2002.59 Hz. The tones are
keyed at a rate of 21.53 baud, so each one lasts for 1/21.53 = 0.04644
seconds. The sync tone is ON during every 3rd transmission interval;
tones representing two data characters follow each sync tone. The
transmission rate of user data is therefore (2/3)*21.53 = 14.4
characters per second. The transmitted signal sounds a bit like
piccolo music.
2. Basic operation is very similar to FSK441. Just select JT6M from
the WSJT "Mode" menu (or use "Shift-F7") and then proceed as usual.
3. The green line and waterfall display have their usual meanings.
4. The program attempts to decode both single pings and an "average
message". The average is the last line displayed during each decoding
attempt, and is flagged with an asterisk as in FSK441. The number to
the right of the asterisk is the inferred message length (for example,
the number should be 10 for the message "W8WN K1JT "). If the program
finds the wrong length, the average will be garbled or meaningless.
All message lengths should be even numbers, because odd-length
messages are padded with an extra space at transmission time in order
to make them even.
5. Clicking with the left mouse button decodes a 4-second block of
data near the mouse pointer. The right button uses a longer segment
of 10 seconds. Drag the mouse with the button down to select any
desired region. Experiment for best decoding as necessary.
6. As soon as you see some properly decoded text, set the DF box to
the measured DF and check the "Freeze" box. Alternatively, you can
set the Tolerance to a low value (say 25 Hz) after the desired signal
has been identified. Use RIT, if necessary, to bring subsequently
measured DF's down to a small value.
7. Default settings for the decoder are S > -12 dB, Tol=400 Hz, DF=0
Hz.
8. JT6M can work with signals that are up to 13 dB weaker than those
required for FSK441. In the brief on-the-air tests I've made with
W8WN, we have both found that mouse-clicking on the smooth green line,
even where nothing was heard and nothing can be seen, sometimes causes
both callsigns to pop up out of the noise!
Please email me with your experience in using the new mode. No doubt
I have forgotten something important somewhere, or perhaps you can
make the program crash. All suggestions for improvements are very
welcome!
-- 73, Joe, K1JT
Email: [email protected]