How to use
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For those familiar with WSJT-X, the use of SlowJT9 should be pretty selfexplaining. But keep in mind that the funcionality is not completely identical to WSJT-X.

 

After launching SlowJT9 a pop up window will appear that will allow you to load the content of a ADIF (ADI or ADX format) logbook:

 

 

The logbook must at least have following fields:

Click on Logbook to select a log. Next select the band and mode(s). Only QSOs with this band and mode(s) will be loaded from the log.

Mode:

Load the log by clicking on OK or continue without loading a log by clicking on Cancel.

 

After launching SlowJT9 for the first time a "Failed to read settings" warning will appears as the settings file is not yet existing. Before you can use the application for transmitting you have to enter some information. Therefore click on settings:

Station:
In order to enable transmitting it is obligatory to enter a valid call and a 4 or 6 digit WW locator (eg. JO20 or J020IX). For PSKReporter spotting a 6 digit locator is required. If the entries are valid the background colour will change from red to cream.
Optional the difference between the computer clock and UTC can be set.
Confirm the settings by clicking on OK or leave without changes by clicking on Cancel.
Radio:
The transmit/receive switchting can be done by VOX or PPT via the RTS or DTR pin of a serial port. The default setting is VOX. If RTS or DTR is choosen you must select a serial port.
If a serial port is selected DTR and RTS can be assigned either as PTT or as alert.
If a serial port pin is assigned as alert it will become high if any alert message is received (see alert below for more details). It is up to you drive whatever you want via this pin.
In case of an alert the background colour of the date & time display will turn red. Click on the date & time display to reset the alert.
Optional a TX delay (not effective if VOX is choosen) and/or watchdog timer(1) (up to 99 minutes, 0 = no watchdog timer) can be set.
Confirm the settings by clicking on OK or leave without changes by clicking on Cancel.
 
Note that for PTT switching via a serial port in most cases an interface between the computer serial port pin and the transmitter PTT input is required:

Audio:
Select the correct input (receive) and output (transmit) channel of the soundcard. In general these should be the same as used for WSJT-X.
Confirm the settings by clicking on OK or leave without changes by clicking on Cancel.
Mode:
Select the mode you want tu use:
  • JT9-1 is the original 1 minute cycle JT9 mode, as used in WSJT-X.
  • JT9-2 is the 2 minute cycle JT9 mode.
  • JT9-5 is the 5 minute cycle JT9 mode.
  • JT9-10 is the 10 minute cycle JT9 mode.

Properties:
  • Tone spacing: in case the exciter signal is divide the tone spacing must be multiplied by the divider ratio in order to get the correct tone spacing for the transmitted signal. Any value between 1 (default, no multiplication) and 9999 can be set.
  • Enable TX after selecting DX call or message: allow automatic reply (transmission) after clicking on a DX call or message.
  • Show TX messages in RX frequency window: your own transmission will be shown in the RX frequency window with a yellow background colour.
  • Discard the default audio frequency limits(1) on TX: the TX boundaries will be 100 - 4980 Hz regardless of the JT9 submode.
  • Discard the default audio frequency limits(1) on RX: discard the RX boundaries. The lower boundary will be 100 Hz, the upper boundary however will still be limited by the resampling process, being 4980 Hz for JT9-1, 2240 Hz for JT9-2, 840 Hz for JT9-5 and 415 Hz for JT9-10.
  • Allow multiple decoding: check this box to enable multiple decoding. But keep in mind that multipe encoding can be very demanding on the CPU of your computer!
    If "Multiple decoding" is enabled the received audio will first be decoded the audio as it is (unshifted) and then it will be shifted +/- 1 second in time steps of 0.2 seconds and decoded again for each step. Thus there will 11 decoding steps in total. However decoding always will stopped at 1 second before the end of the cycle at latest, so the next cycle will not be corrupted. Decoding can also be stopped by clicking on the Band activity or RX frequency windows. After each decoding step the new (non-duplicate) decoded messages will be shown.
    During the decoding process any already decoded message can be selected by triple-clicking on it (a single click for stopping the decoding followed by a double click for selecting the message).
    Be aware that each decoding time can take several seconds on a slow computer, in that case only a limited number of decoding steps will be performed.
    The DT parameter in the Band activity or RX frequency windows will show the time shift of the decoded file. "0.00" means that the message is retrieved from the unshifted (original) audio, any other value means it is retrieved from shifted audio (and thus would be missed without multiple decoding).
Confirm the settings by clicking on OK or leave without changes by clicking on Cancel.
Save:
Select what you want to save:
  • The incoming audio files (WAV format) for later use. The WAV files will be stored in the folder "save". Be aware that this will fill your harddisk at a rate of ± 1.5MB per minute.
  • Decoded messages. All decoded messages will be saved in the file "decoded.txt" than can be found in the folder "extra".
  • Debug information. An number of program steps will be recorded in the file "debug.txt" than can be found in the folder "extra". Saving debug information can be useful to trace errors (bugs) that occur. If you want to report a bug I strongly recommend to run SlowJT9 with "Save debug information" activated, and include (a part of debug.txt) in your bug report.
Be aware that none of these files will be automaticaly deleted. The files "decoded.txt" and "debug.txt" should not be edited nor deleted while SlowJT9 is running.
Confirm the settings by clicking on OK or leave without changes by clicking on Cancel.
Reporting:
PSK reporter:
Spotting of the received signal to PSKReporter.info(4) can be enabled / disabled.
If you want to spot to PSR Reporter as listener only (SWL) an ID must be entered.

UDP broadcast:
UDP broadcast allows an application to send messages to all computers in a LAN. In case of SlowJT9 all decoded messages will be broadcasted.
You need to give:
  • The IP address (127.0.0.1 for a local area network).
  • The port number (2239 default for SlowJT9). Ensure not to use a port that is already occupied by another application (in particular 2237, the default port used by WSJT-X).
SlowJT9 Monitor is a small application that receives and displays UDP broadcasted messages (including audio alert). This application is meant to be installed on another computer. If you install it on the same computer as SlowJT9 ensure that the applications are not using the same audio output!
SlowJT9 Monitor can be downloaded here.

Confirm the settings by clicking on OK or leave without changes by clicking on Cancel.
Alert:
Alert if:
Select what messages will trigger an alert and will be UDP broadcasted:
  • If your callsign is received (someone calling you).
  • If a new call is received (station you did not work before).
  • If a new DXCC entity is received.
  • If a new US state is received.
  • If any DX call is received.
  • If a new DX call is received (DX station you did not work before).
  • Include stations (these callsigns will always trigger an alert regardless of other settings). Callsigns must be separated by a single space.
  • Exclude stations (these callsigns will never trigger an alert regardless of other settings). Callsigns must be separated by a single space.
The DXCC entity of a call is determined using the CTY.DAT file maintained by Jim Reisert, AD1C.
The US state of a call is determined using the WAS.DAT(5) file. Both files can be found in the "tables" folder.

Update at startup:
Select what files will be updated when launching SlowJT9:
  • CTY.DAT (Amateur Radio Country Files) used to determine the DXCC entity of a callsign.
  • WAS.DAT(5) (US State file) used to determine the US State of a callsign.
For file updating an internet connection is required.

Confirm the settings by clicking on OK or leave without changes by clicking on Cancel.
Front End Mixer:
The resampling and decoding process limits the maximum RX audio frequency to 4980 Hz for JT9-1, 2240 Hz for JT9-2, 840 Hz for JT9-5 and 415 Hz for JT9-10. This can be inconvenient if a higher RX audio frequency is needed to fit the signal in the passband of a narrow filter.
This can be fixed by using the Front End Mixer that downconverts the incoming audio signal (fOUT = fIN - fLO).
E.g.: if you want to downconvert the 1200..1400 Hz incoming audio to 400..600 Hz the local oscillator frequency must be set to 800 Hz.
Be aware that:
  • No filtering of the input signal is done. Unwanted mixer products are attenuated by at least 50dB. This can be improved by narrow band filtering (such as a RX CW filter) of the signal.
  • Downconversion will reduce the audio range.
    E.g.: If the local oscillator frequency is set to 800 Hz the incoming audio frequency range from 900 Hz to (almost) 1600 Hz will be downconverted to 100 Hz to 800 Hz. Signals outside the 900 .. 1600 Hz range will be lost!
  • The local oscillator frequency can be set in the range 200 .. 20000 Hz.
If the front end mixer is enabled this is indicated by dial label text colour turning red:
Confirm the settings by clicking on OK or leave without changes by clicking on Cancel.

 

After setting all required parameters you are ready to use SlowJT9.

 

 

  1. Open this help file.
  2. View the "must read" message. Please read and understand this message before using SlowJT9.
  3. Open the settings, see above.
  4. Open the spectrum window, see further.
  5. Band activity window. All messages received within the audio bandwidth(1) are displayed here. CQ messages have a green background colour, messages that contain your call have a red background colour and alert messages have an orange background colour.
  6. Tune : click to tune / stop tuning (toggle function).
  7. Halt TX : click to stop the transmission instantly ("emergency stop").
  8. Enable TX : click to enable / disable transmitting (toggle function).
  9. Erase : click to erase alle messages in the RX frequency window, double-click to erase all messages in the band activity window.
  10. Check this box if you want to transmit the first cycle(2), uncheck to transmit the second cycle(2).
  11. Check this box if you only want to change your RX frequency if you click on a call in the band activity or RX frequency windows. If unchecked both RX and TX frequency will change.
  12. DX call field. Enter the DX call here, either by typing or double-clicking in the band activity window or RX frequency window. The text colour will turn red for a new callsign (not worked before). The background colour is red if the DX call is missing or invalid and will turn to cream for a valid call.
  13. Audio input level bar.
  14. Approximate distance (km). Is only displayed is the locator grid is known.
  15. Dial frequency, enter the frequency in Hz en press [enter]. Required only if you want to spot to PSKReporter.info(4). Changes will become effective only after pressing [enter] or 5 seconds of no keyboard activity! The background colour is red for an invalid input, green for a valid input and cream is the input is effective.
  16. Audio input level display. The background colour is red in case of overload and orange if the level is too low.
  17. Mode display (JT9-1, JT9-2, JT9-5 or JT9-10).
  18. Interrupt occupancy. The soundcard data is loaded and handled every 200ms. The interrupt occupancy indicates the percentage of time spent on the interrupt handling. The background colour is green for < 25%, yellow for 25..50%, orange for 50..75% and red for > 75%.
  19. Cycle progress bar. The colour is red for TX, green for RX and yellow if idle. In addition the current status, and in TX the current transmitted message, is displayed.
  20. DXCC entity (main prefix). Only shown if a valid DX call is available. The text colour will turn red for a new DXCC entity.
  21. Date & time display. Make sure that time is set to UTC, either by setting the computer clock or bu setting the UTC difference in the settings (see above).
    In case of an alert the background colour of the date a time display will turn red. Click on the date & time display to reset the alert.
  22. Log DX call. This will add the DX call to the list of worked stations and eventually update the worked DXCC and/or US States lists. But it will NOT add anything to your logbook!
  23. TX audio frequency field. The frequency must be within the allowed audio range(1). The frequency can be changed by typing or using the up/down arrows. Changes will become effective only after pressing [enter] or 5 seconds of no keyboard activity! The background colour is red for an invalid input, green for a valid input and cream is the input is effective. Unless the "hold TX frequency" box is checked the frequency will also be changed by double-clicking on a message in the band activity or RX frequency window.
  24. RX audio frequency field. The frequency must be within the allowed audio range(1). The frequency can be changed by typing or using the up/down arrows. Changes will become effective only after pressing [enter] or 5 seconds of no keyboard activity! The background colour is red for an invalid input, green for a valid input and cream is the input is effective. The frequency will also be changed by double-clicking on a message in the band activity or RX frequency window.
  25. Check this box if you want to ommit the exchange of the WW locator if responding to a CQ call. Instead you will immediately send the report.
  26. Watchdog timer(2) countdown display, only active if the watchdog timer is enabled. The watchdog timer can be reset by clicking on this display.
  27. Report field. The report must be in the range of -50 to +49 dB. The report can be set or changed by typing or using the up/down arrows. The report will also be changed by double-clicking on a message in the band activity or RX frequency window. The background colour is red if the report is missing or invalid and will turn to cream for a valid report.
  28. RX ← TX : click to set the RX frequency equal to the TX frequency.
  29. TX ← RX : click to set the TX frequency equal to the RX frequency.
  30. Free message field. You can enter up to 13 characters. Allowed charachers are 0..9 A..Z space - @ # < > ? . / +. Double-click to clear this field.
  31. Structured message field. Messages are generated by clicking on one of the CQ Grid dB R+dB RRR 73 buttons or on a message in the band activity or RX frequency window. You cannot type in this field.
  32. Check this box to transmit the structured message.
  33. Check this box to transmit the free message.
  34. Audio output level slider. Use it to adjust the audio ouput level.
  35. Structured message buttons. Click on one of there buttons to generate a structured message. Structured messages can only be generated if the required information (DX call and/or report) is available.
  36. Current cycle(3) display. While for JT9(-1) it is very straighforward to know the current cycle (even minute = 1st cycle, odd minute = 2nd cycle), this is not so for JT9-2 and JT9-5. So for your convenience the current cycle is displayed.
  37. RX frequency window. All messages received on (or very close to) the RX frequency are displayed here. CQ messages have a green background colour, messages that contain your call have a red background colour.
  38. Cycle length of received message: 1 = JT9(-1), 2 = JT9-2, 5 = JT9-5, X = JT9-10.
  39. Minimize the application
  40. Close SlowJT9.

Spectrum window:

 

 

  1. Close the spectrum view window.
  2. Lower frequency limit adjustment (100 - 4900 Hz in 100 Hz steps).
  3. Upper frequency limit adjustment (200 - 5000 Hz in 100 Hz steps).
  4. TX frequency marker. Any frequency limits will be shown as a gray bar.
  5. RX frequency marker. Any frequency limits will be shown as a gray bar.
  6. Frequency axis (in Hz).
  7. Gain / offset slider.
  8. Waterfall display. Click on the waterfall display to set the RX frequency, double-click to set the TX and RX frequency.
  9. If "Gain" is selected (green background colour) the slider will adjust the gain. Click to select.
  10. If "Offs" is selected (green background colour) the slider will adjust the offset. Click to select.
  11. If "AGC" is selected (green background colour) the gain will be automaticaly adjusted. Click to enable / disable (toggle function).
  12. Signal level to colour conversion column. Can be adjusted by changing the visual gain and noise reference level.
  13. "Black level" offset. Any signal below this level will be black on the the spectrum display.
  14. Spectrum display. Click on the spectrum display to set the "black level" offset.

 

(1) The default audio bandwidth is 200 - 1400 Hz for JT9-1 and JT9-2, 200 - 843 Hz for JT9-5, 200 - 416 Hz for JT9-10. This limitations can be discarded (Settings → Mode).

(2) The cycle duration is 1 minute for JT9(-1), 2 minutes for JT9-2, 5 minutes for JT9-5 and 10 minutes for JT9-10. The first cycle starts at the full hour and from then on first and second cycles follow each other alternately:

  • JT9-1:
    • 12:00-12:01 = 1st cycle
    • 12:01-12:02 = 2nd cycle
    • 12:02-12:03 = 1st cycle
    • 12:03-12:04 = 2nd cycle
    • ...
    • 12:56-12:57 = 1st cycle
    • 12:57-12:58 = 2nd cycle
    • 12:58-12:59 = 1st cycle
    • 12:59-13:00 = 2nd cycle
  • JT9-2:
    • 12:00-12:02 = 1st cycle
    • 12:02-12:04 = 2nd cycle
    • 12:04-12:06 = 1st cycle
    • 12:06-12:08 = 2nd cycle
    • ...
    • 12:52-12:54 = 1st cycle
    • 12:54-12:56 = 2nd cycle
    • 12:56-12:58 = 1st cycle
    • 12:58-13:00 = 2nd cycle
  • JT9-5:
    • 12:00-12:05 = 1st cycle
    • 12:05-12:10 = 2nd cycle
    • 12:10-12:15 = 1st cycle
    • 12:15-12:20 = 2nd cycle
    • ...
    • 12:40-12:45 = 1st cycle
    • 12:45-12:50 = 2nd cycle
    • 12:50-12:55 = 1st cycle
    • 12:55-13:00 = 2nd cycle
  • JT9-10:
    • 12:00-12:10 = 1st cycle
    • 12:10-12:20 = 2nd cycle
    • 12:20-12:30 = 1st cycle
    • 12:30-12:40 = 2nd cycle
    • 12:40-12:50 = 1st cycle
    • 12:50-13:00 = 2nd cycle

(3) The watchdog timer, if active, will stop transmission when it trips. The time can be set between 0 (not active) and 99 minutes. The watchdog times can be reset by clicking on the watchdog timer countdown display. It is also reset by initiating a generated message.

(4) In order to send spots to PSKReporter.info:

Only captured messages with a valid callsign and WW-locator (4 or 6 digits) will be uploaded to PSKReporter.info.
Important: JT9-2, JT9-5 and JT9-10 spots can only be seen at PSKReporter.info if "JT" or "all modes" is selected. If "JT9" is selected only JT9-1 spots will be shown.

(5) WAS.DAT file:
The WAS.DAT file is used to determine the US State of a call. It was created based on the US MF active operator list by Ralph, W0RPK.
This file is in plain text, with one callsign preceded by the state (2 character abbreviation) + a single space per line.
Eg:
AL N4WLO
AK KL7L
AZ K7PO
CA NU6O
CA N1VF
CA KR7O
...