Category Archives: JT9

My experience with JT-65/JT-9 modes

Well, I’ve been using JT65 and JT9 modes (I will reffer them as JT65 from now on) for more than 3 years now and I would like to share some experiences on using these modes in order to help fellow hams to join them.

The main points to take care in order to work JT65 are:

  • A very accurate time.
  • An adecuate audio input to the program. Too much audio will overload the audio card and distort the results. Too little audio will avoid the audio card to detect the signals.
  • A rig capable of being activated via VOX or via CAT.

I currently own two rigs capable of work JT65:

  • A Kenwood TS430S and
  • A Flex-1500 (5w QRP) on steroids with a HardRock 50 power amp.

Regarding the TS-430s I connect the rig by using a tigertronics USB, this is a USB sound card that connects to the audio input and output of my transceiver and my computer. The computer sees it as a USB sound card and microphone. The TS430s gets activated via PTT when my tigertronics USB gets some signal injected from my program to its microphone.

By using my kenwood ts430s I can not use CAT, so I can not change frequencies, oh also I can not work in split mode, it means my rig is tuned to a single frequency and I must manually change it whenever I change bands. By not being able to work split, I can not work JT9 at the same time I work JT65 (JT9 is +2khz above the JT65 frequency).

As you can see, the kenwood rig is quite old, and even with the inconveniences I have stated before I can work and I have worked tons of stations in JT65/JT9 (and of course CW, PSK31, etc).

Regarding my Flex-1500:

It is a SDR radio I bought 5 years ago, when I re-started in radio. It is a 5W QRP transceiver I can control from my computer. It is, I can change bands from the program (PowerSDR) and tune AGC, powerlevels, filters, etc from it.

It has several “BUTs”:

  1. It has not an internal ATU, so changing bands has to be manually done in order to use an external tunner.
  2. It has only 5watts. I really love QRP but from time to time love to use some extra “punch”.
  3. A powerfull PC capable of processing the signals from my SDR radio. SDR is not for weak proccessor PCs… you actually need quite a powerfull one, if possible core2duo and UP.

I solved issues 1 and 2 by building a HardRock-50 with the ATU kit. It took me, I don’t know, maybe 6 hours to finish building with the help of my daughter (she loves picking resistors, and holding the PCB and so on).

I connected the HR-50 and the flex-1500 via a serial port cable and now my flex-1500 “informs” the HR-50 when PTT is pushed. The band changes are being issued from the WSJT-x program via a program called DDUtil to the HR-50 and to the Flex-1500.

This is because CAT was conceived a 2 ways communication. It is: when I change bands from my WSJT-x program, it only communicates to a single CAT device. However I need to inform two: my power amp and my flex-1500 radio. DDUtil helps you with this. It acts as a CAT device, receives the band change command, and replicate that command to my two devices (flex-1500 and hr-50).

This way I can change bands and keep myself busy in 20m and 10m usually.

Oh, yes, BTW, I operate my shack somehow remotedly. Instead of standing in front of my shack 24×7, I installed a VNC server to my shack PC and I can control it from my laptop anywhere Im at home: bed, dinner table, watching a baseball game, etc.

Here is a video of a QSO with a fellow ham in France.

Compiling and installing wsjt-x for Fedora-20 and Fedora-21

Hi, this tutorial is my first step to create an rpm package for wsjt-x for Fedora.

I started trying to understand the somehow cryptic instructions written here:

In fact it has a small problem: when you try to svn using berlios, it fails.

I guess somehow the script is old and the code no longer resides in berlios.

The other small issue is that the instructions in that document are for debian-like distros. I guess they actually like ubuntu and/or debian and Fedora looks unstable for them. It is their right to use any other Linux distro.. and ours to use Fedora.

For me, and for several others, Fedora has been running very very well for years (I’ve been using it since Fedora-9) so with little effort we can “port” the instructions to Fedora and enjoy wsjt-x in such a wonderful distro.

Im running Fedora-20 now, but I guess this instructions will work for Fedora-18, Fedora-19 and the future Fedoras.

and yes, I will try to create an rpm package for easier distribution.. later. as of now, you can follow the instructions in this page:


This was the hardest part: To discover the needed packages for compiling wsjt-x. I had to go over the compile process once and again until I was able to discover the needed packages for fedora. You will install these ones:

yum install hamlib hamlib-devel cmake qt5-qtbase qt5-qtbase-devel subversion \
qt5-qtmultimedia qt5-qtmultimedia-devel gcc-gfortran gcc-c++ ftw fftw-devel glibc.i686 gcc-libgfortran.i686 libgfortran.i686

why glibc.i686 and gcc-libgfortran.i686? Well, almost everybody runs 64-bits Linux in these ages, but there is some proprietary program called kvasd that wsjtx needs. And kvasd is compiled for 32-bits arch as of now.

The other packages are needed for wsjtx to run, and the *-devel are needed for it to compile.

If you notice Im missing some other packages, it is because I compiled in a non-clean system, I mean, I ran it in a system I used to work from time to time so some packages could have been installed previously.. so let me know if you notice Im missing some packages to be installed.

Downloading the source code

this is easy, we use svn to download the code onto some dir:

mkdir wsjt-env
cd wsjt-env
svn co svn://
export BUILD_DIR=~/wsjt-env/wsjtx
cd wsjtx
export rev_num=`egrep “Rev:” mainwindow.cpp |awk ‘{print $4}’`

We first went to our $HOME dir. Then created wsjt-env and cd to wsjt-env.

Then we downloaded, using svn, the latest source code.

We exported the variable BUILD_DIR to match the directory where the source code was downloaded.

Finally we moved to wsjtx and stored in rev_num the current revision number. (I had to change the way we obtain the revision number from the original script).


Compiling is easy as well.. if all packages are already installed, then you should simply follow these steps:

cd lib
make -f Makefile.linux
cd ..
export QT_SELECT=qt5
j_c=$(grep -c ^processor /proc/cpuinfo)
make -j$j_c

If you had some errors, it means we are missing to install some packages.. let me know.

If everything went ok… let “install” wsjtx:

Installing wsjtx

cd ..
mv ./wsjtx-$rev_num ./wsjtx-$rev_num-$(date +%F-%H%M) &> /dev/null
mv ./wsjtx_install ./wsjtx-$rev_num
cd ./wsjtx-$rev_num
cp ../wsjtx/*.dat ../wsjtx/*.txt ./
# you can download cty.dat directly from
# rm -f cty.dat
# wget
cp -R ../wsjtx/Palettes/ ../wsjtx/samples/ ./
rm ./CMake*
rm -rf ../wsjtx

And we are done.. we can start wsjtx by doing this:


donw forget to remember where this binary is located so you can start it later:



Contacto con K1JT

Justo el primer día que comienzo a utilizar el modo JT9 y pum.. me contacta K1JT. Es un rafioaficionado creador de este tipo de modo de emisión, por eso el modo tiene JT en su nombre (WSJT), por sus iniciales, por sus indicativos.

Pero además es un astrofísico ganador de un premio Nobel (y muchos premios más) Joe Taylor. En fin, que no todos los días un premio Nobel se interesa en hablar contigo!

k1jt - hc6ep - JT9 - QSO