|Kendall Amateur Radio Society||
WSJT-X On A Raspberry Pi 3
Joe Kohler, W5QLF
the March STXDXCC Club meeting the experimenter and consummate gadgeteer,
Tom, AB5XZ, brought a brand new, out-of-the-box Raspberry Pi 3
(RPi 3) card sized computer for show-and-tell.
When you do that kind of thing at a gathering of hams, the most
likely result is a conversation on how you can apply such a gadget to
side conversation before the meeting started the topic surrounded
whether such a cute little QSL card sized computer could run a heavy
weight computational program such as Joe Taylor's WSJT-X and whether
this little computer could be interfaced to a transceiver in the typical
paper describes some of the things to be done to coax (no cable
intended) a Raspberry Pi into running the latest digital mode on the
air. The FT-8 digital mode
was announced on June 29, 2017 and was an immediate hit with operators
all over the world. The
initial version of WSJT-X that included the FT-8 mode was1.8.0 rc3.
The FT-8 protocol is a digital mode program with a 15 second
transmit/receive cycle time as well as very capable weak signal
performance. The WSJT-X
version discussed in this paper is the 1.9.0 rc3 Beta version released
on March 18, 2018. This more
advanced version of WSJT-X is so described as it is currently downloaded
and installed automatically using the Raspberry Pi "Raspbian"
Raspberry Pi 3 Model B (Hardware)
is the latest model available in a series of small computer cards that
use ARM (Advanced RISC Machine) processors by Broadcom Corporation.
The Raspberry Pi 3 uses a BCM 2837B0 with a 1.2 GHz 64-bit
quad-core processor. The
computer board contains four USB ports, a HTMI video output and built in
wi-fi and blue tooth interfaces. An
external 5 volt, 1.5 amp power supply is required as well as an HTMI
video terminal, keyboard and mouse.
The computer operating system, Raspbian, is a Linux derivative of
Debian Linux ported for use with the ARM processor.
The latest release is version 9 and is named "Stretch"
Comparison of WSJT-X Requirements and The
Raspberry Pi 3
For The Raspberry Pi (RPi)
WSJT-X website lists software versions compiled for three operating
systems: Windows, Macintosh OS X and Linux.
See reference 1. The
Linux versions supporting WSJT-X include:
Debian, Ubuntu (32 bit)
Debian, Ubuntu (64 bit)
Fedora, RedHat (32 bit)
Fedora, RedHat (64 bit)
Raspbian, Jessie, ARMv6
(Raspberry Pi compatible)
that Raspbian version 9 (Stretch) is backward compatible with Raspbian
version 8 (Jessie). Either OS
version will support WSJT-X. Also
note that although the Raspberry Pi 3 uses a 64 bit processor, The
Raspbian OS is a 32 bit system and WSJT-X for RPi is a 32 bit application.
Loading WSJT-X on
you have your Raspberry Pi 3 up and running with Raspbian Graphical User
Interface (GUI) screen displayed and the Internet connected you are ready
to download and launch Joe Taylor's multi-mode digital program, WSJT-X.
Select the applications menu by clicking on the Raspberry icon in
the upper left hand corner of the GUI screen.
Next select the "Preferences" menu item and then the
"Add/Remove Software" item.
Enter the character string "WSJTX" in the box right under
the "Options" label in the upper left hand corner and hit Enter.
WSJT-X Version 18.104.22.16876 Found And Ready to Download
Click on the line containing the WSJT-X items to download and
install. Once installed the
WSJT-X icon will appear on the desktop window of the Raspbian GUI screen.
Double click on this icon to launch the program.
WSJT-X Downloaded, Installed and Ready To Run
To Your Station
your USB devices for rig control and sound card.
The W5QLF station has an Icom 746 equipped with a CI-V to USB cable
for Computer Aided Tuning (CAT) for rig control and a SignaLink USB sound
card device. Plug the USB
cables from the transceiver CAT terminal and the SignaLink USB device into
the Raspberry Pi 3 computer. Power
up or reboot the RPI so the Raspbian OS can find the new USB devices.
Tuning (Rig Control)
the WSJT-X software to recognize the CAT USB signals.
the "Files/Settings" menu item in WSJT-X and select the
"General" tab and input your station information.
Click on the "Radio" tab and select your radio type.
You will note that Raspbian has defined a “tty” port
automatically. Input the baud
rate your radio is set for and select the appropriate PTT method for your
station setup. There is a TEST
CAT button that turns green when the correct parameters have been set for
your CAT setup.
that Linux does not use COM port but instead uses a device/tty
nomenclature. In the case of a
USB CAT cable, Raspbian will assign "USBx" as the port address.
Other parameters to be set on this screen include:
DTR High, RTS High
(This allows the RPi to power the electronics in the CI-V to USB
(SignaLink units use a tone detector to key the PTT line.
This simplifies the unit setup considerably)
on the Test CAT button to test this function
If the button turns green and you hear your transceiver change
band, life is good. If all is
silent and the button turns red, start your CAT trouble shooting
Duplex Audio Lines
Open the Audio tab and view the "Sound Card Input: and Output:" items. The RPi presented as many as 14 options to select for the audio connections. Some of these items such as "surroundxx" reflect audio drivers that are not used in this application. You'll probably have to try several different selections until you see the waterfall display light up. The selection that worked on the W5QLF system was: "sysdefault:CARD=CODEC". "default" also worked.
Configure The Duplex Audio Channel To Your
this stage you ought to be able to see signals on the waterfall and in the
Band Activity window. You may
have to set the transmit power level using the "Tune" button on
the right hand side at mid level on the screen.
The slider labeled "Pwr" on the lower right side of the
screen controls the level of the output tone and this also affects the RF
output level. Since the JT
modes use only one tone at a time, this mode is much more tolerant of
transmitter intermodulation than phase sensitive modes such as PSK-31.
Waterfall and Spectrum
Display On Wide Graph
Band Activity Window Active
On The 20 Meter Frequency
is a "Log QSO" button on the left side of the midlevel buttons.
This brings up a small window where you can complete manual inputs
to the logging info such as TX Pwr. Once
you click OK the log data is written as comma delimited file in wsjtx.log
and an ADIF file in wsjtx_log.adi. These
files are accessed by selecting the "File/open log directory.
Location Of Logged QSO Data
In Two Formats
all has worked well up to this point, you are now ready to start making
a complex digital program to run on a puny computer such as a Raspberry Pi
is surprisingly satisfying. Certainly,
the use of USB interfaces for rig control and audio links greatly
simplifies the hardware setup. The
USB hardware used is exactly the same equipment as used on this
transceiver when running digital programs on a Windows machine.
initial thoughts were to try to configure the Raspberry Pi to control WSJT-X
on a FlexRadio. The FlexRadio
software has features that replace hardware cables with virtual lines that
connect the computer with the FlexRadio via an ethernet connection.
This is great as it eliminates cable tangles, outboard sound cards
and CAT interface issues! Wow,
I'm really on a roll!
Wait, There is more: SmartSDR
is only available for Windows and iOS for Apple devices.
There is no Linux version of SmartSDR and the DAX and CAT routines
won't run on Linux. Therefore,
it is not possible to connect a Raspberry Pi running WSJT-X to a FlexRadio
via virtual (DAX and CAT) connections.
running SmartSDR on an outboard Windows computer work nicely with digital
mode programs also running on the Windows computer.
the new model 6400 and 6600 FlexRadios or FlexRadios using Maestro with
internal computer devices appear not have provisions for running third
party digital mode programs or rig connected logging programs.
Apparently, an outboard PC computer is required to run digital
modes or logging programs with CAT capability just as with the earlier
model FlexRadios. (Reference 7)
Reference 8, Paragraph 10:
"How do I operate digital modes with
the FLEX-6400M and FLEX-6600M? You can continue
to use your favorite digital mode software on your PC just as you do today
but without the need for a sound card or cables. Simply load SmartSDR™
software on the PC running your digital software and connect through
FlexRadio’s Digital Audio Exchange (DAX) and SmartSDR CAT eliminating
the problems with wiring complexity and RF/audio ground loops."
WSJT-X Release Notes Version 1.8.0 by Joe Taylor, K1JT
A general description of WSJT-X that includes the FT-8 mode
Raspberry Pi 3 Setup Raspbian, Fldigi, WSJT-X by DL1GKK
Installing Operating System Images for RPi
How To Get Raspbian Stretch (scroll down)
Setting up FT-8 by Jim Carson
Flex 6xxx and Digital Modes Via Remote Connection
FLEX-6400/6400M/6600/6600M FlexRadio Systems Document