fldigi - digital modem program for hamradio operators
is a cross-platform multi-modem program for most of the digital
modes used by radio amateurs today: CW, PSK, MFSK, MT-63, RTTY, Hellschreiber,
DominoEX, Olivia, THOR and Throb are all supported. It can also help calibrate
a sound card to a time signal and do on-air frequency measurement tests.
Fldigi features basic rig control, logging, and contest operation,
“panoramic” PSK decoding, a PSK Reporter client, and remote
control via XML-RPC.
Long options begin with two hyphens and are handled by fldigi. The option names
may be abbreviated to any unambiguous substring, and the option argument may
be separated from the name by a space or equals sign, as per getopt(3).
Short options begin with a single hyphen and are passed directly to FLTK. They
may be abbreviated only as indicated.
Look for and store configuration files in
directory DIRECTORY, which is created if it does not exist. Defaults to
Set the receive message queue key. May be
given in hex if prefixed with “0x”. Defaults to
“9876” or “0x2694”.
Set the transmit message queue key. May be
given in hex if prefixed with “0x”. Defaults to
“6789” or “0x1a85”.
Set the ARQ TCP server address. Defaults to
“127.0.0.1”. HOSTNAME may be any node name string
accepted by getaddrinfo(3).
Set the ARQ TCP server port. Defaults to
“7322”. PORT may be any service name string
accepted by getaddrinfo(3).
options are only available if fldigi was built with
Set the XML-RPC server address. Defaults to
Set the XML-RPC server port. Defaults to
Allow only the methods whose names match
REGEX. REGEX is a POSIX extended regular expression.
Allow only the methods whose names do not
List all available XML-RPC methods and exit.
May be preceded by the --xmlrpc-allow or --xmlrpc-deny options
to verify their effect.
Perform the CPU speed test that is normally
done when fldigi is run without an existing configuration directory. Results
are shown in the event log and options may be changed to the recommended
values for the measured CPU speed.
Unhide controls for adding noise to the
Hide all main window widgets except the menu
bar and waterfall (with its associated controls). Meant to be used with
external programs that control fldigi with XML-RPC.
Set the event log verbosity. LEVEL is
clamped to the range [0,5]; for Quiet, Error, Warning,
Info, Verbose and Debug. Defaults to “3”
Print version information and exit.
Print build information and exit.
Print options summary and exit.
-bg, -background COLOUR
Set the background colour.
-bg2, -background2 COLOUR
Set the secondary (text) background
-di, -display DISPLAY
Specifies the X server to connect to; see
or -nodn, -nodnd
Enable or disable drag and drop copy and paste
in text fields.
-fg, -foreground COLOUR
Set the foreground colour.
-g, -geometry GEOMETRY
Set the initial window size and position.
Fldigi may not honour this option.
Start fldigi in iconified state. Fldigi may
not honour this option.
or -nok, -nokbd
Enable or disable visible keyboard focus in
-na, -name CLASSNAME
Set the window class. Defaults to
-ti, -title WINDOWTITLE
Set the window title. Defaults to
“fldigi - <callsign>”.
Set the widget font and (optionally) size.
Defaults to “sans:12”.
The --benchmark-* options are only enabled if fldigi was built (exclusively) for
benchmarking and batch decoding.
Specify the modem. Defaults to
Set the modem frequency in Hz. Defaults to
Enable or disable modem AFC. Defaults to
Enable or disable modem squelch. Defaults to
Set the modem squelch level (1—100%).
Defaults to “0.0”.
Specify the input. Must be a positive integer
indicating the number of samples of silence to generate as the input, or, if
fldigi was linked with libsndfile, the name of the input audio file. The
filename must contain non-digit characters.
Specify the output data file. Non-textual
output (i.e. Hellschreiber or MFSK images) cannot be saved. Default: decoder
output is discarded.
Specify the sample rate conversion ratio.
Defaults to “1.0” (input is not resampled).
Set the sample rate conversion type. TYPE is
an integer in the range [0,4]. Defaults to “2” (“Fastest
The following options should not be relied upon. They are listed here only
for the sake of completeness, and may be replaced by GUI settings or removed
altogether in a future version.
Set the waterfall width.
Set the waterfall height.
Set the minimum window width.
Set the minimum window height.
Run for approximately SECONDS
Set frames per buffer option to FRAMES
when creating PortAudio streams. Defaults to “0” (let PortAudio
Fldigi uses several environment variables, mainly set for child processes
created by the <EXEC> macro and the notifier.
The web browser to use for http and file URIs.
Overrides $BROWSER and xdg-open(1).
The following variables are created in the environment of the child process that
is forked by the <EXEC>
macro. They are empty if values are not
The receive message queue key.
The transmit message queue key.
The XML-RPC server address string.
The XML-RPC server port string.
The ARQ server address string.
The ARQ server port string.
The version string.
The process ID of the parent fldigi
The configuration directory.
The operator’s callsign.
The operator’s name.
The operator’s IARU (Maidenhead)
The short modem name.
The long modem name.
The rig (radio) frequency.
The modem (audio) centre frequency.
The actual receive/transmit frequency, i.e.
the sum of rig and modem frequencies taking into account the rig
The text (frequency in MHz) contained in the
QSO Freq log field.
The text (QSO start time) contained in the
(time) On log field.
The text (QSO end time) contained in the
(time) Off log field.
The text (other station’s callsign)
contained in the Call log field.
The text (other station’s name)
contained in the Name log field.
The text (received RST) contained in the (RST)
In log field.
The text (sent RST) contained in the (RST)
Out log field.
The text (other station’s QTH)
contained in the QTH log field.
The text (other station’s Maidenhead
locator) contained in the Loc log field.
The text (free-form notes) contained in the
Notes log field.
The text (azimuth in degrees to other station)
contained in the Az log field.
The following variables are created in the environment of child processes
created by the notifier.
These variables (i in [0,9]) contain
substrings matched by capturing groups in the event’s regular
expression. 0 contains the whole matched text.
The number of substrings available.
Builtin event types that match callsigns will
place the callsign in this variable.
The complete string that matched the
event’s regular expression.
The modem frequency.
The event type.
The station’s country name (for events
of type "station heard twice").
The following variables are only used if fldigi was built with debugging support
), or they are only useful when debugging specific
If set, this variable disables glibc’s
malloc debugging, which fldigi enables by default when built for
Traces Fl::lock() calls.
Initialises hamlib in debug mode.
Fldigi is licensed under the GNU GPL, which grants you the right to run the
program for any purpose (freedom 0). However, permission to use it for the
transmission of radio signals can only be obtained from the communications
authority of your country. When given, this permission almost always comes in
the form of an amateur radio license.
If you do not have an amateur radio license you can still have fun using fldigi
as a shortwave listener. One way to do so is by using the builtin PSK Reporter
client to submit realtime spots of transmitting stations; see RESOURCES below.
All you need is a computer, homebrew SDR receiver, and simple wire antenna!
Various files and subdirectories are created in $HOME/.fldigi. Some of the most
interesting ones are listed below.
The main settings file.
The “status” file. Stores window
geometries, button states, current modem, current audio frequency, squelch
level, and so on.
The event log.
The default macro file.
This directory contains waterfall
This directory is added to the PATH
environment variable of the child process that runs <EXEC> macros.
This directory contains logged received and
sent text (when such logging is enabled), including the default logbook
Received MFSK images are automatically saved
in this directory.
This file is written by the frequency analysis
modem. The fields are dial frequency, audio frequency, and offset. See
documentation for details.
The following files are used if present. They must be downloaded and copied to
~/.fldigi/ by the user.
List of DXCC entities and callsign prefixes;
used to display tooltips in the received text buffer, and also to auto-fill
the Country, Locator and Azimuth log fields. Available at
List of known LOTW users (one callsign per
line); used for the received text tooltips. Available at
AGMemberList.txt or eqsl.txt
List of “Authenticity
Guaranteed” eQSL users (one callsign per line); used for the received
text tooltips. Available at http://www.eqsl.cc/QSLcard/Programming.cfm.
fldigi --wfall-height 144 --font sans:11 -fg "#c0c0c0" -bg
"#5f5f63" -bg2 "#19213b"
This is how the author of this document
fldigi --xmlrpc-deny "main.(tx|tune|run_macro)"
Unregister XML-RPC methods that may
ssh -L 7362:localhost:7362 remote-host xvfb-run fldigi -display :99
Start fldigi on remote-host under a
“fake” X server. (The xvfb-run(1) utility is available on Debian
systems). The remote “headless” fldigi is then controlled via
XML-RPC on port 7362, i.e from flrig, flamp etc.
fldigi --benchmark-input 480000 --benchmark-modem 1
Benchmark the DominoEX-4 modem with 480K audio
fldigi --benchmark-input audio.wav --benchmark-modem 25 --benchmark-frequency
1500 --benchmark-afc 1 --benchmark-squelch 1 --benchmark-squelch-level 5.0
Read audio.wav (whose sample rate must
be 8000Hz in this case) and decode BPSK-31 signals at 1500Hz. AFC is enabled
and the squelch is set to 5%. Decoded text is saved to out.txt.
fldigi-shell(1), gmfsk(1), gpsk31(1), grig(1), rigctl(1), xlog(1),
getaddrinfo(3), getopt(3), regex(7), X(7)
Main web site: http://www.w1hkj.com/Fldigi.html
Sourceforge project page: http://sourceforge.net/projects/fldigi/
Wiki and bug tracker: https://fedorahosted.org/fldigi/
More information on MFSK16, DominoEX and other digital modes can be found at
http://www.qsl.net/zl1bpu/ and http://www.w1hkj.com/FldigiHelp/Modes/index.htm
The PSK Automatic Propagation Reporter site can be found at
Fldigi was written by
•David Freese, W1HKJ.
•Stelios Bounanos, M0GLD.
•Leigh L. Klotz, Jr., WA5ZNU.
Fldigi also includes code written by others. Among them are
•Tomi Manninen, OH2BNS.
•Pawel Jalocha, SP9VRC.
•Hamish Moffatt, VK3SB.
This manual page was written by Stelios Bounanos <sb[at]enotty(dot)net>.
License GPLv3+: GNU GPL version 3 or later.