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Tutorial for WSJT 5.9+ | To use it effectively you must
download and install
a package of sample WSJT wave files. (22
MB).
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If you are new to WSJT or would like to become more adept in its use,
the following step-by-step tutorial might help. To use it you
must first obtain the collection of sample wave files
available (Linux version
here).
These files are on-the-air recordings of meteor pings in FSK441 mode,
pings and ionospheric scatter signals in JT6M mode, and EME signals in
the JT65 modes. The package of sample files is about 22 MB in
size. The tutorial's main emphasis is on the decoding of signals
received by WSJT. For other aspects of the program's use, refer
to the User's Guide.
Basic instructions for the tutorial follow.
0. Important pre-requisite: please read and keep at hand the most
up-to-date WSJT User's Guide and related documentation. WSJT
is a
complicated program, and you will gain skill with it more quickly
if you make good use of the manuals. (Even though
documentation
for the latest WSJT version is not yet available, most material in
the older manuals still applies.)
1. If you have already installed and used a version of WSJT6, delete
your WSJT.INI file or rename it to something else, temporarily.
This will ensure that you start the tutorial with everything in the
default configuration.
2. To install WSJT6 (version 5.9.0) in Windows, execute the file
WSJT590.EXE. The default installation directory is C:\Program
Files\WSJT6. (Linux installation instructions still to be
written... In the meantime, you must compile it yourself.)
3. Install the sample files to your WSJT6 directory by executing the
file WSJT6_Samples.EXE (Windows) or by extracting the tarfile
WSJT6_Samples.tgz (Linux).
4. Double-click on the WSJT6 desktop icon to start the program in
Windows. (Position the main WSJT6 window conveniently on your
screen. You may ignore or minimize the other two windows for
now.)
In Linux, start the program by typing "wsjt6" or "python -O
wsjt.py".
From here onward, instructions for Windows and Linux are the same.
5. By default WSJT starts in FSK441 mode (yellow label at bottom left
of status bar). Select menu item File -> Open and navigate to
subdirectory RxWav\Samples\FSK441 under your WSJT6 installation
directory. Double-click on the first file in this directory,
K5CZD_050723_134100.WAV. The file will be opened and a
2-dimensional spectrogram displayed in the main graphical area.
Click the Decode button to decode the file, producing the following
text in the main text box:
134100 27.4 220 6 26 -21
O1JT 26 K5CZD 2626 K1JT 27 K5CZ #6
According to the line of decoded text, this file contains a meteor
"ping" at t=27.4 s, lasting 220 ms, with (S+N)/N = 6 dB. You
can
see that K5CZD is sending K1JT the signal report "26". In
FSK441
and JT6M modes it is not uncommon to see incorrect characters near
the ends of decoded sequences, where the signal became weak.
Refer
to the WSJT User's Guide for additional details on message
structure and information reported by the decoders.
6. Hit the F6 key (or select File -> Open next in directory) to open
and decode successive files in the FSK441 directory. These
files
contain recordings of K8EB calling KB4BWW, KC0HLN calling CQ and
then working K1JT, KM5ES working K1JT, KM5PO calling K1JT as a
"tailender", and finally N9EGT calling CQ. With any of these
files
you should try left- and right-clicking on the pings to cause the
program to decode at a particular location in the file. You
can
also try clicking on pure noise, away from any ping; you should
then see only garbage as decoded text. You may click Erase
and
Decode at any time to clear the display areas and decode the most
recently analyzed file again.
7. Open the first KC0HLN file again. It produces the message
001400 6.5 400 15 27 -21
2 CQ KC0HLN EN32 CQ KC0HLN E/31 GQ#GBYLE
Double-click on the callsign KC0HLN in the text window, and watch
what happens in the Tx message boxes. The program is now
ready for
K1JT to answer this CQ.
8. Exit and restart the program, and then hit Shift-F7 to switch to
JT6M mode. Select File -> Open, navigate to inside the
subfolder
RxWav\Samples\JT6M under your WSJT6 installation directory, and
double-click on the AA9MY file. You should see a message in
which
AA9MY is finishing a QSO by sending "73 DE AA9MY":
142300 15.1 1.2 -2 -15
9MY 73 DE AA9MF2
The AA9MY signal is rather weaker than those in the FSK441
examples. Try listening to any of the files using Windows
Sound
Recorder, to get a feeling for what they sound like.
9. Hit F6 to open and decode successive files in the JT6M directory.
You should see AC5TM working K1SIX, AF4O working K1JT, and WA5UFH
working K0AWU. In several files the signals are frequently
inaudible or barely audible, yet decodable. The second AF4O
file
produces no decoded text by default, but try right-clicking at
t=17.6 s. (The file time corresconding to the location of the
mouse pointer is displayed in a green label at lower left of the
plot area.) You should be able to find several other examples
of
decodable text in flat regions on the green curve. For
example,
try left-clicking at t=7.4 s or t=10.8 s in the first AF4O file, or
t=12.8 s in the second AF4O file.
10. Hit F8 to switch to mode JT65A. You should now pay some
attention
to the SpecJT screen as well as the main WSJT6 screen; select View
-> SpecJT if you have minimized or deleted it. (If the SpecJT
and
WSJT6 windows overlap on your screen, you may reduce the size of
the SpecJT window so that only the top half shows.) Select
speed 3
on the SpecJT screen and check the following items on the SpecJT
Options menu: Mark T/R boundaries, Flatten spectra, Mark JT65 tones
only if Freeze is checked, JT65 DF axis. Select File -> Open
on
the main screen, navigate to inside the JT65A directory, and
double-click on the F9HS file name. The SpecJT screen will
show a
messy spectrum cluttered with birdies at 100 Hz intervals and other
interfering signals. However, the red curve in the
main-screen
graphical area suggests a possible JT65 sync tone amongst the
clutter. No decoded text appears, but the program does report
a
possibly significant detection at sync=1 and signal level -23 dB.
The reported width of the sync tone is 5 Hz, which is larger than
optimum for the JT65A mode.
To examine further, check AFC and then click Decode. You will
see
F9HS answering the CQ of K1JT:
074800 1 -23 2.7 363 5 *
K1JT F9HS JN23
Double-click on F9HS in the text window. You should see F9HS
copied into the To Radio box; the database will be searched and the
grid locator entered, if available; Tx messages will be generated
for a QSO with F9HS, and the Tx message pointer will be set to
message number 2 so that a signal report will be sent. During
real
operation, all of this can take place in the few seconds near the
end of a reception interval, before you start transmitting again.
11. Uncheck AFC and hit F6 to open the next file. A smaller red
spike
appears, but again there is no decoded text. The SpecJT
waterfall
clearly shows a weak signal, and this time there is no significant
interference. Go to the menu Decode -> JT65 and change the
"Normal" decoding option to "Exhaustive", then click the Decode
button again. This time WSJT will "think" a bit longer, and
you
will see that G3FPQ is calling W7GJ:
131900 1 -25 1.5 42 3 *
W7GJ G3FPQ IO91
Exhaustive decoding can take up to twice as long as Normal
decoding, but it is more sensitive. If your computer has a
1.5 GHz
or faster CPU, you will probably want to use Exhaustive all the
time.
12. Hit F6 again to select the third JT65A file. The waterfall
shows
a clear signal that drifts upward by about 15 Hz during the
transmission. Again no decoded text appears. Perhaps
AFC will
accommodate the drift? Click AFC and then Decode; still no
good.
In desperation (perhaps you need Montana for 2m WAS?) clear AFC and
click "Include" to instruct the program to do its best, even though
it may consider the synchronization to be sub-par. Voila!
W7GJ is
sending K1JT the OOO signal report.
13. Hit Shift-F8 to select JT65B mode. Then select File -> Open,
navigate to inside the JT65B directory, and open the DL7UAE file.
The waterfall shows a strong birdie at DF=783 Hz and several weaker
signals. The ones at DF=223 and DF=244 Hz look most
interesting
because they show the "speckled" QSB typical of EME libration
fading at 2 meters. WSJT chooses the signal at DF=223 Hz as
the
most promising, and decodes it to reveal DL7UAE answering a CQ from
K1JT.
The red curve shows a second spike that looks almost as good as the
DL7UAE signal. Experiment to see if you can determine who
else
might be calling. (The answer and how to find it are given
below.)
14. When you are ready to continue, clear Freeze (you may also want to
invoke Erase and Clr Avg) and hit F6 to open the next file.
The
green curve shows some nasty SSB QRM starting at t=5.3 s into the
file. (Again, you might want to listen to the file.)
Some
rhythmic broadband noise is also present, showing clearly on the
green line. Fortunately, the waterfall looks nearly clean in
the
important JT65 spectral region, and WSJT has no problem decoding
the signal at DF=-46 Hz. EA5SE is sending K1JT the OOO signal
report.
Try double-clicking on the sync tone in the waterfall, or on the
red spike in the main-screen graphics area. Either action
will
automatically set DF to the selected frequency, Freeze ON and
Tol=50 Hz, and will then invoke the decoder. You can see on
the
red curve that the sync-tone search range has been reduced to a
range +/- 50 Hz around the selected frequency offset, DF.
Take note of the colored tick marks on the frequency scale at the
top of the SpecJT screen. The leftmost vertical green mark
shows
the selected DF, and the horizontal band below it shows the range
searched for a sync tone. The other green tick marks the
upper
limit of the JT65 data tones, and red ticks mark the upper
frequencies that would be used for shorthand messages.
15. Hit F6 to open the next file. You will see EA5SE sending
K1JT the
shorthand message RRR. Magenta and orange curves in the
main-screen graphics area plot the measured spectra for the two
phases of the shorthand message cycle. In the waterfall
display
you should see the alternating tones for RRR accurately aligned
with the sync-tone marker and the second red marker. Hit the
F6
key once more to decode the final transmission of this QSO, with
ES5SE sending 73 to K1JT.
16. Uncheck Freeze and hit F6 again. The waterfall shows a
likely
sync tone with deep libration fading at DF=-22 Hz. The
program
decodes EI4DQ sending K1JT the OOO signal report.
Double-click on
the sync tone in either window to lock him in, and hit F6 to open
the next file. Evidently he has received my OOO report, and
is now
sending RO.
17. Clear the Freeze box and hit F6 again to open the next file.
Two
birdies are in the passband, but WSJT ignores them and finds a
valid sync tone at DF=223 Hz, decoding IK1UWL sending an OOO report
to K1JT. Double-click on the sync tone to lock him in, and
wait
for the next transmission (i.e., hit F6). He has copied my
RO, so
he is sending RRR. Note that this shorthand message is barely
visible on the waterfall, but it is still decoded correctly.
K1JT
would now send 73 to signify that the QSO is complete.
18. Clear the Freeze box and hit F6 to find RU1AA calling CQ.
Alex is
always loud; these signals are easily audible. In the next
several
files we work him quickly, despite two birdies that are drifting
down through his JT65 signal passband. Notice that as a
reminder,
decoded shorthand messages are always flagged with a "?" mark
unless you have turned Freez ON and set Tol to 100 Hz or less --
which you should always do, for best results.
Alex ends the QSO by sending the message "TNX JOE -14 73" to tell
me that my signal peaked at -14 dB. Since this message does
not
start with two callsigns (or CQ or QRZ plus one callsign) it is
treated as a plain text message. Such messages can convey
only 13
characters, so in this case the final "3" was truncated.
19. Clear the Freeze box and hit F6 to show another big Russian
signal: RW1AY/1 is answering a CQ from K1JT. Double-click on
the
sync tone (on either window) to lock it in, and then hit F6 to see
the "RO", "73", "-19TNXQSO 73" contents of the next three
transmissions.
20. Were you able to decode the second station answering my CQ in the
DL7UAE file? If so, congratulations! If not, clear
Freeze and go
back to File -> Open and select the first file again.
Left-click
on the smaller red spike, check Freeze ON, and reduce Tol to 10 Hz.
Then hit Decode, and you will see SP6GWB calling with an excellent
signal. The DL7UAE and SP6GWB signals are separated by only
22 Hz,
so most of their tones overlap in the 355 Hz passband of JT65B.
Nevertheless, the decoder copies perfectly through the resulting
QRM with the help of its robust error-correcting code.
21. While you have the DL7UAE file in memory, Freeze ON, Tol=10 Hz,
and DF set on the smaller red spike, hit F2 to open the Setup ->
Options screen and enter your own call (or some other call) in
place of K1JT in the "My Call" box. Then dismiss the Options
screen and try to decode the SP6GWB signal again. You will
surely
fail, because for this message successful copy was obtained as a
result from the Deep Search decoder. (Callsigns in the
CALL3.TXT
database are paired up with CQ and with the "MyCall" entry,
encoded, and compared with the received information. If the
signals match to within a specified minimum confidence level, the
matching message is displayed.) If no good match is found,
there
is a small chance that you will see a low-confidence false decode.
It will usually be flagged with a "?" mark to remind you to
exercise your own judgment, based on signal strength, sync level,
displayed graphical information and your accumulated JT65
experience, as to whether the message can be accepted as valid.
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