@@ -920,8 +931,8 @@ modulator (TX) and demodulator (RX) sample clocks. For example if the
transmit station sound card is sampling at 44000 Hz and the receive
station sound card 44001 Hz, the sample clock offset would be
((44000-44001)/44000)*1E6 = 22.7 ppm.
-13.2 Timing Delta Tab
+14.2 Timing Delta Tab
This indicates the symbol timing estimate of the demodulator, in the
range of +/- 0.5 of a symbol. With off air signals this will have a
sawtooth appearance, as the demod tracks the modulator sample clock. The
@@ -932,12 +943,12 @@ Offset Bug
Testing a FDMDV
Modem
-13.3 Sound Card Debug
+14.3 Sound Card Debug
These features were added for FreeDV 700D, to help diagnose sound
card issues during development.
-
+
Debug FIFO and PortAudio counters: used for debugging audio problems
on 700D. During beta testing there were problems with break up in the
700D TX and RX audio on Windows.
@@ -970,8 +981,8 @@ TX FIFO sending samples to the TX. If this hits zero, your TX audio will
break up and the RX will lose sync. TX audio break up will also occur if
you see “outfifo1” being incremented on the “Fifo” line during TX. Try
increasing the FifoSize.
-13.4 Full Duplex Testing with
+14.4 Full Duplex Testing with
loopback
Tools - Options - Half Duplex check box
FreeDV GUI can operate in full duplex mode which is useful for
@@ -985,8 +996,8 @@ the sound cards.
In Tools - Audio Config - Receive Tab - From Radio select -> Loopback: Loopback PCM (hw:1,0)
- Transmit Tab - To Radio select -> Loopback: Loopback PCM (hw:1,1)
-13.5 Experimental Features
+14.5 Experimental Features
Occasionally there are some features that may be unstable or
otherwise not ready to officially be released. To experiment with these
features, you can go to Tools->Options->Debugging and enable
@@ -995,8 +1006,8 @@ enabling this setting, it is recommended to disable it again to verify
that an experimental feature is not causing trouble. (Additionally, if
you’re able to confirm that an experimental feature is causing problems,
please file a bug report!)
-14 Tips
+15 Tips
- The space bar can be used to toggle PTT.
- For modes other than RADEV1, you can left click on the main window
@@ -1004,10 +1015,10 @@ to adjust tuning. The vertical red line on the frequency scale will show
the current center frequency and FreeDV will automatically track any
drift once it syncs.
-15 Common Problems
-15.1 FreeDV Sets Radio To Wrong
+16 Common Problems
+16.1 FreeDV Sets Radio To Wrong
Mode
By default, FreeDV attempts to set the radio’s mode to DIGU/USB-D (or
LSB equivalent for 40 meters and below). Some radios do not support data
@@ -1018,8 +1029,8 @@ LSB modes for rig control instead.
Note that for best results, your radio should have all processing
disabled if you’re using the standard USB/LSB modes. This disabling of
processing typically takes place when using data mode.
-15.2 Overdriving Transmit
+16.2 Overdriving Transmit
Level
This is a very common problem for first time FreeDV users. Adjust
your transmit levels so the ALC is just being nudged. More power is not
@@ -1027,9 +1038,9 @@ better with FreeDV. An overdriven signal will have poor SNR at the
receiver. For FreeDV 700D/700E operation with the clipper, make sure
your transmitter can sustain high average power levels without damage
(e.g. 40W RMS on a 100W PEP radio).
-15.3 I can’t set up FreeDV,
+class="header-section-number">16.3 I can’t set up FreeDV,
especially the Sound Cards
This can be challenging the first time around:
@@ -1039,9 +1050,9 @@ especially the Sound Cards
mailing list. Be specific about the hardware you have and the exact
nature of your problem.
-
The most common issue with Icom radios is that the CI-V address
configured in FreeDV does not match the address configured in the radio.
@@ -1051,9 +1062,9 @@ Transceive” option is enabled on the radio or else the radio will not
respond to requests directed to that address.
On newer radios (e.g. 7300, 7610), you may also need to set “CI-V USB
Echo Back” to ON as this may be set to OFF by default.
-15.5 Hamlib seems not reliable on
+class="header-section-number">16.5 Hamlib seems not reliable on
my Linux machine
Some Linux distributions come with pre-installed software that may
try to use serial ports that your radio creates. You may have problems
@@ -1075,9 +1086,9 @@ radio.
sudo systemctl stop ModemManager
sudo systemctl disable ModemManager
sudo systemctl mask ModemManager
-15.6 I’m using OmniRig and have
+class="header-section-number">16.6 I’m using OmniRig and have
problems with rig control
If you’re using OmniRig and have problems getting rig control to
work, please attempt to update the INI files for OmniRig. These can be
@@ -1085,9 +1096,9 @@ found by going here and
clicking on the “INI files for OmniRig” link. There may also be a newer
OmniRig version available at that same link which could work better if
you are running an older version.
-15.7 I need help with my radio or
+class="header-section-number">16.7 I need help with my radio or
rig interface
There are many radios, many computers, and many sound cards. It is
impossible to test them all. Many radios have intricate menus with
@@ -1095,8 +1106,8 @@ custom settings. It is unreasonable to expect the authors of FreeDV to
have special knowledge of your exact hardware.
However someone may have worked through the same problem as you. Ask
on the digital voice mailing list.
-15.8 Can’t hear anything on
+16.8 Can’t hear anything on
receive
Many FreeDV modes will not play any audio if there is no valid
signal. You may also have squelch set too high. In some modes the
@@ -1104,8 +1115,8 @@ signal. You may also have squelch set too high. In some modes the
from the SSB radio.
Try the Test Wave Files above to get a feel for what a FreeDV signal
looks and sounds like.
-15.9 Hearing myself whenever I
+16.9 Hearing myself whenever I
transmit
Verify audio device settings in FreeDV. If your audio settings are
correct, there are a few other possibilities:
@@ -1115,23 +1126,23 @@ devices used with FreeDV.
Turn off TX monitoring (right-click on PTT button and make sure
“Monitor transmitted audio” is unchecked).
-15.10 The signal is strong but
+class="header-section-number">16.10 The signal is strong but
FreeDV won’t get sync and decode
Do you have the correct sideband? See USB or LSB section.
Is it a FreeDV signal? SSTV uses similar frequencies. To understand
what FreeDV sounds like, see the Test Wave Files section.
-15.11 Trouble getting Sync with
+16.11 Trouble getting Sync with
700D
You need to be within +/- 60 Hz on the transmit signal. It helps if
both the TX and RX stations tune to known, exact frequencies such as
exactly 7.177MHz. On channels with fast fading sync may take a few
seconds.
-15.12 PTT doesn’t work. It works
+class="header-section-number">16.12 PTT doesn’t work. It works
with Fldigi and other Hamlib applications.
Many people struggle with initial CAT control and PTT setup:
@@ -1147,9 +1158,9 @@ you a member of the dialout group?
hardware, what you have tried, and the exact nature of the
problem.
-15.13 I’m on Windows and serial
+class="header-section-number">16.13 I’m on Windows and serial
port PTT doesn’t work with my USB to serial adapter.
Please verify that you are running the correct drivers for the USB to
serial adapter that you’re using. Information and download links for the
@@ -1169,22 +1180,22 @@ for instructions on doing so in Windows 10. For Windows 8:
Check the “automatically get the device app” option, then click Save
changes to save the settings you just chose.
-15.14 I installed a new version and
+class="header-section-number">16.14 I installed a new version and
FreeDV stopped working
You may need to clean out the previous configuration. Try Tools -
Restore Defaults. Set up your sound cards again with Tools - Audio
Config.
-15.15 FreeDV crashes when I press
+16.15 FreeDV crashes when I press
Start
Have you removed/changed USB audio devices? If you remove/change USB
audio devices without pressing Tools - Audio Config, FreeDV may crash.
See Changing Audio Devices above.
-15.16 FreeDV can’t be opened on
+class="header-section-number">16.16 FreeDV can’t be opened on
macOS because the developer cannot be verified
From January 2020 Apple is enforcing notarization for all macOS
applications. While official releases of FreeDV are signed, other types
@@ -1200,16 +1211,16 @@ execute FreeDV, run the following from Terminal:
xattr -d com.apple.quarantine FreeDV.app
or
xattr -d -r com.apple.quarantine FreeDV.app
-15.17 I’m on a Mac and my preferred
+class="header-section-number">16.17 I’m on a Mac and my preferred
audio device isn’t appearing
macOS has a longstanding issue that prevents certain audio devices
from appearing. More info here.
-15.18 FreeDV doesn’t preserve
+class="header-section-number">16.18 FreeDV doesn’t preserve
window positions on Linux
Many Linux distributions are switching away from X11 and towards a
new GUI system known as Wayland. Wayland explicitly does not support
@@ -1218,14 +1229,14 @@ compositor to control window positioning. You can force use of X11 via
the Xwayland compatibility layer by adding GDK_BACKEND=x11
to your environment to regain the ability to preserve window positioning
if desired.
-16 Converting this document to
+17 Converting this document to
PDF
For the Linux inclined:
$ pandoc USER_MANUAL.md -o USER_MANUAL.pdf "-fmarkdown-implicit_figures -o" \
--from=markdown -V geometry:margin=.4in --toc --highlight-style=espresso
-17 Glossary
+18 Glossary
@@ -1254,10 +1265,10 @@ speech codec bits
-18 Release Notes
-18.1 V2.4.0 TBD 2026
+19 Release Notes
+19.1 V2.4.0 TBD 2026
- Bugfixes:
@@ -1277,6 +1288,7 @@ data-cites="barjac">@barjac!
- Enhancements:
- Add UDP broadcast of received callsigns. (PR #1367)
+- Add Time-Out Timer (TOT) capability to FreeDV. (PR #1366)
- Load last-used config file on restarts. (PR #1365, #1371)
- Add “Set tune output to minimum” to Tune button context menu for
safety. (PR #1378) - thanks @barjac!
#1368)
-18.2 V2.3.1 May 2026
+19.2 V2.3.1 May 2026
- Bugfixes:
@@ -1332,8 +1344,8 @@ class="citation" data-cites="barjac">@barjac!
- Clarify Reporter on/off tooltip. (PR #1345)
-18.3 V2.3.0 May 2026
+19.3 V2.3.0 May 2026
- Bugfixes:
@@ -1436,13 +1448,13 @@ thanks @barjac!
maintenance. (PR #1286, #1307)
-18.4 Earlier than V2.2.0
+19.4 Earlier than V2.2.0
See this
for more information about changes in versions prior to 2.2.0.
-19 References
+20 References
-