DIY Arduino CW decoder

A holiday activity, build your own CW decoder that can handle up to 40 WPM including logic control to determine the CW code speed. There is a 567 tone decoder chip and some signal pre-processing, 8 ohm stereo audio goes in, next you print the decoded text on the serial output and on the LCD screen.

Version 2.4 has a status bar, most left number counts frames, then WPM guess followed by quality parameters.

This is version 2.3 that includes a quality of code filter.

This is version 2 that clearly had some bugs that were fixed

Note: I’m not sharing too much details yet because I’m still working on the software which is roughly 1000 lines in C/C++ Arduino style, still it compiles to 11k of code and  less than 1 k of variables. The hardware resembles the design made by WB7FHC Budd but I’ve changed some stuff before it goes in the 567 tone decoder IC. The magazine Electron Dec 2018 jaargang 73 discusses a similar project.

Last update: 9-jan-2019


The save directory in WSJT-X

In wsjt-x there is a save directory, like c:\users\admin\appdata\local\wsjt-x\save which started to collect some 30Gb of data and something line 38+ thousand wav and C2 files in the 2,5 years that I used wsjt-x. The 30 Gb is not really a problem, but I don’t like the 38+ thousand files because it slows down windows 7, for instance because of backups and virus scanners checking the system. So why is this happening? The answer is that the developers and testers use the save directory files but it is probably not helping the average user. Also, my impression is that “save everything” was a default setting in the past. If you are not a developer then:

  1. clear everything in the save directory, you don’t need it.
  2. go to menu ->  save and select none

You will still see that wsjt-x writes files in the save directory, but it also removes the files when the program is properly closed. Occasionally you can clear the save directory (under file -> delete all *.wav & *.c2 files in SaveDir) because there will probably be unattended wsjt-x occasions with a PC restarting after a windows update (for instance). So repeat the clean procedure once per month.

After running in this way for a day I still found files in the save directory. This sounds more like a bug in WSJT-x, in actually all versions.

Last update: 16-dec-2018 10:51


Please update to WSJT-X V2.0.0 GA

At this moment (12-dec-2018) you should consider an update to WSJT-X V2.0.0 GA which clearly has several advantages as the release notes and the user guide explain. At the same time install NTP and openssh. Installing NTP makes a significant difference because WSJT-X depends on accurate timing. If you are more than 2.5 seconds off then your transmissions  simply fail. (The 2.5 seconds is a guess). Windows is by itself sloppy on internet time synchronisation and a separate NTP from Meinberg does a better job. The openssh package (you only need the DLL actually) is required because of LOTW access by the software. This transition period may take a while, either because people are late with their updates, either because it is not always an easy job on each operating system.

Last update: 12-dec-2018

Screen Shot 2018-12-13 at 13.08.40

FT8 different versions, 80 and 40m bands, last 24 hours (now:13-12-2018 13:12 CET)

Be careful with new release candidates for WSJT-X

Most of the FT8 users will presently use WSJT-X release 1.9.1,  but as you can read here new release candidates are available. The next general release will be wsjt-x 2.0.0. GA on the 10th of December. Everything beyond release 1.9.1 is not downward compatible, so nobody will hear you when you go to beta release 2.0.0. rc5 and likewise, you will not hear anyone else when you are running 2.0.0 rc5. (The story is more complicated with earlier rc’s under 2.0.0, but I want to skip that topic here)

This is a bit of a problem, so it is good to have both versions of the WSJT-X software available until everyone is convinced that WSJT-X 2.0.0 GA is the way to go. What you want to do during installation is to tell the installer to write to a new directory. Presently the code and all native data is in c:\wsjt\wsjt. Well, don’t overwrite that directory, but instead install the new release to c:\wsjt\wsjt_200_rc5 or something similar. (It is possible with the windows installer, I’m not sure how to do this on different platforms.) Put both icons on your desktop and this should solve the problem temporarily.

A separate story is the user administration data, your ADI files and other stuff. This is stored as user data under admin\appdata\local\wsjt-x (I’m admin, if you are joe then replace admin by joe) and you should simply keep it there, unless you want to start all over again which you probably don’t want to do.

Hope this helps

Last update: 5-dec-2018