FreeDV GUI (or just FreeDV) is a GUI program for Linux, Windows, and macOS for running FreeDV on a desktop PC or laptop.
This is a live document. Notes on new FreeDV features are being added as they are developed.
This section contains instructions to help you get started.
FreeDV is officially supported on the following operating systems and versions:
While it may be possible to execute FreeDV on additional platforms and distributions (especially ones similar to ones currently supported), this is not guaranteed. Any bugfixes required for an unsupported platform may be deferred or rejected, especially if there is impact to supported platforms. Requests for official support of new platforms should go through our existing Feature Request process.
Upon starting FreeDV for the first time, the Setup Wizard dialog will appear. This is a streamlined setup process for FreeDV optimized for hardware commonly used by amateur radio operators and is divided into four sections:
Note that you can always return to this dialog by going to Settings->Setup Wizard.
To configure your sound card(s) using the Setup Wizard, simply select the sound device(s) associated with your radio and the microphone and speaker devices you wish to use to hear decoded audio as well as to transmit audio. If you’re setting up a receive-only station, you can check “Receive only” when prompted.
Setup Wizard supports three methods of radio control:
Simply select the option that matches your radio setup and the required fields will appear. For Hamlib, these are typically the type of radio you’re using as well as the serial port it’s connected to (or TCP/IP hostname:port). Serial port PTT control requires the serial port your radio is using as well as whether your radio’s PTT is triggered via the RTS or DTR pin (and the required polarity for either).
While not required, it is recommended to enable reporting so that others can see who is currently receiving them. This also allows the FreeDV application to control the radio’s frequency and mode. Both sides of a contact must have this enabled in order for contacts to be reported. To configure reporting, simply enable the feature here and enter your callsign and current grid square/locator.
For more information about the reporting feature, see the “FreeDV Reporting” section below.
For this setup, you just need the basic sound hardware in your computer, for example a microphone/speaker on your computer.
When you press Start FreeDV will start decoding any incoming signals on the microphone input, playing the decoded audio out of your speaker. If no valid FreeDV signals are received, no audio will be played.
If you connect the microphone input on your computer to your radio receiver, you can decode off air signals. If you have a rig interface, try configuring that as the From Radio To Computer device, with your computer’s sound card as the From Computer To Speaker/Headphone device.
If you don’t have anyone to transmit FreeDV signals to you, try the test wave files in the next section.
For TX/RX operation you need to configure two sound cards, by setting up Tools - Audio Config Transmit and Receive Tabs.
When receiving, FreeDV off-air signals from your radio are decoded by your computer and sent to your speaker/headphones, where you can listen to them.
When transmitting, FreeDV takes your voice from the microphone, and encodes it to a FreeDV signal in you computer which is sent to your radio for transmission over the air.
| Tab | Sound Device | Notes |
|---|---|---|
| Receive Tab | Input To Computer From Radio | The off air FreeDV signal from your radio rig interface to your computer |
| Receive Tab | Output From Computer To Speaker/Headphones | The decoded audio from your computer to your Speaker/Headphones |
| Transmit Tab | Input From Microphone To Computer | Your voice from the microphone to your computer |
| Transmit Tab | Output From Computer To Radio | The FreeDV signal from your computer sent to your rig interface for TX |
If you change audio devices (e.g. add or remove sound cards, USB hardware), it’s a good idea to check the Tools/Audio Config dialog before pressing Start, to verify the audio devices are as expected. This is particularly important if any audio devices e.g. Headsets, USB Sound Cards, or Virtual Cables have been disconnected since the last time FreeDV was used.
Hitting Refresh in the lower left hand corner of the Tools/Audio Config will normally update the audio devices list. Keeping a screen shot of a known working configuration will be useful for new users. Unexpected audio configuration changes may also occur following a Windows updates.
Another solution is to re-start FreeDV and check Tools/Audio Config again after changing any audio hardware.
The Tools->CAT and PTT Config dialog supports three different ways to control PTT on your radio:
You may also optionally configure an additional serial port for PTT input. This can be useful for interfacing devices like foot switches to FreeDV. If configured, FreeDV will switch into transmit mode (including sending the needed Hamlib or serial commands to initiate PTT) when it detects the configured signal.
Once you have configured PTT, try the Test button.
Serial PTT support is complex. We get many reports that FreeDV PTT doesn’t work on a particular radio, but may work fine with other programs such as Fldigi. This is often a mismatch between the serial parameters Hamlib is using with FreeDV and your radio. For example you may have changed the default serial rate on your radio. Carefully check the serial parameters on your radio match those used by FreeDV in the PTT Dialog.
Also see Common Problems section of this manual.
Hamlib comes with a default serial rate for each radio. If your radio has a different serial rate change the Serial Rate drop down box to match your radio.
When Test is pressed, the “Serial Params” field is populated and displayed. This will help track down any mismatches between Hamlib and your radio.
If you are really stuck, download Hamlib and test your radio’s PTT
using the command line rigctl program.
If using an Icom radio, Hamlib will use the radio’s default CI-V address when connecting. If this has been changed, you can specify the correct address in the “Radio Address” field (valid values are 00 through FF in hexadecimal).
Note that “00” is the “wildcard” CI-V address. Your radio must have the “CI-V Transceive” option enabled in order for it to respond to commands to that address. Otherwise, FreeDV must be configured to use the same CI-V address as configured in the radio. For best results, ensure that there are no other Icom/CI-V capable devices in the chain if “00”/“CI-V Transceive” is used.
If you change the COM port of a USB-Serial device in Device Manager, please unplug and plug back in the USB device. Windows/FreeDV won’t recognize the device on the new COM Port until it has been unplugged/plugged.
In the installation are audio files containing off-air FreeDV modem signals. There is one file per FreeDV mode and are in the following locations depending on platform:
| Platform | Typical Location |
|---|---|
| Windows | C:\Program Files\FreeDV [version]\share\freedv-gui\wav |
| Linux | /usr/share/freedv-gui/wav or /usr/local/share/freedv-gui/wav |
| macOS | See https://github.com/drowe67/freedv-gui/tree/master/wav |
To play these files, first select a FreeDV mode and press Start. Then choose a file using “Tools - Start/Stop Play File From Radio”. You should then hear decoded FreeDV speech.
These files will give you a feel for what FreeDV signals sound like, and for the basic operation of the FreeDV software.
Sound card levels are generally adjusted in the computer’s Control
Panel or Settings, or in some cases via controls on your rig interface
hardware or menus on your radio. In-app adjustments can also be done
using the TX Attenuation control on the right-hand side
of the main window. The << and >>
buttons adjust by 1.0 dB and the < and >
buttons adjust by 0.2 dB; the mouse scroll wheel can also be used to
generate 0.2dB steps whilst hovering anywhere over the TX Attenuation
control area. Values below 0 dB attenuate the transmit signal.
When FreeDV is running, you can observe the sound card signals in the main window tabs (From Radio, From Mic, To Mod, To Speaker).
On receive, FreeDV is not very sensitive to the From Radio level, adjust so that the Level meter is around 75% scale and not clipping. FreeDV uses phase shift keying (PSK) so is not sensitive to amplitude.
The transmit level from your computer to your radio is important. On transmit, adjust your level so that the ALC is just being nudged. More is not better with the FreeDV transmit signal. Overdriving your transmitter will lead to a distorted transmit signal, and a poor SNR at the receiver. This is a very common problem.
Right-clicking on the TX Attenuation control top row opens a context menu with the following options for the currently active amateur band:
The Control panel (right-hand side) contains a Tune button which outputs a continuous 1500 Hz carrier for antenna matching, netting etc. While Tune is active the TX Attenuation controls adjust the tune signal level rather than the normal transmit level.
Right-clicking the Tune button opens a context menu with the following options:
FreeDV will automatically detect band changes (via Hamlib or OmniRig CAT, or manual frequency entry) and load any saved attenuation value for the new band. When a band is left the current values for that band are saved immediately.
FreeDV 700D and 700E can drive your transmitter at an average power of 40% of its peak power rating. For example 40W RMS for a 100W PEP radio. Make sure your transmitter can handle continuous power output at these levels, and reduce the power if necessary.
Adjust the microphone audio using your operating system’s volume settings so the peaks are not clipping, and the average is about 75% of max scale on the Level meter. If additional adjustments are needed, the “Mic Level” slider on the right hand side of the main window will allow you to adjust audio levels +/- 20 dB. The “From Mic” tab will show audio after Mic Level adjustments, but before AGC (if enabled). If additional adjustments are performed, the peaks in this plot should not exceed approximately +/- 0.5.
AGC is enabled by default and is recommended that it remain on. If desired, it can be disabled by going to Tools->Filters. The “To Mod” plot shows the audio that will ultimately be transmitted out over the air, after AGC (if enabled) processing.
FreeDV likes a clean path through your radio. Turn all audio processing OFF on transmit and receive:
On receive, DSP noise reduction should be off.
On transmit, speech compression should be off.
Keep the receive audio path as “flat” as possible, no special filters.
FreeDV will not work any better if you band pass filter the off air received signals. It has its own, very tight filters in the demodulator.
FreeDV has standardized on upper sideband for RADEV2, regardless of the location in the band. As an aid to this, FreeDV will show the current mode on the bottom of the window upon pressing the Start button if Hamlib is enabled and your radio supports retrieving frequency and mode information over CAT. If your radio is using an unexpected mode, it will display that mode on the bottom of the window next to the Clear button in red letters. When a session is not active, Hamlib isn’t enabled, or if your radio doesn’t support retrieving frequency and mode over CAT, it will remain grayed out with “unk” displaying instead of the mode (for “unknown”).
Note that if in Analog mode, FreeDV will use the appropriate sideband for the band. To ensure that the same portion of spectrum is used by both digital and analog modes FreeDV will adjust the radio frequency by +3kHz on the legacy LSB bands. i.e. 40, 80 and 160 meters. (For example, 7177 kHz becomes 7180 kHz when the Analog button is pushed.)
For most FreeDV use, your radio’s receive and transmit filters should be set to the widest possible (typically around 3 kHz). This allows easy switching between analog mode as well as the various FreeDV modes. There has not been any testing done to definitively confirm whether narrower bandwidths help with reception of FreeDV. Additionally, FreeDV already performs its own transmit filtering, so using additional narrow filtering on the radio will likely have little benefit (again, untested).
The Voice Keyer Button on the front page puts FreeDV and your radio into transmit, reads a wave file of your voice to call CQ, and then switches to receive to see if anyone is replying. If you press the space bar or click the XMIT button, the voice keyer stops. If a signal with a valid sync is received for a few seconds the voice keyer also stops.
The Audio tab inside Settings-Edit Settings can be used to select the wave file, set the RX delay, and number of times the TX/RX cycle repeats.
Additional options are also available if you right-click on the Voice Keyer button:
FreeDV has the ability to monitor transmit audio. This can be useful for adjusting microphone filters when your radio is plugged into a dummy load. To enable this, right-click on the XMIT button and choose “Monitor transmitted audio”. A checkmark will appear next to this menu option when enabled.
To quickly record incoming signals from the radio, a ‘Record’ button is provided in the main window. Clicking this button will create a file beginning with the name “FreeDV_FromRadio” and containing the current date and time. Clicking ‘Record’ again will stop recording.
The Audio tab inside Settings-Edit Settings allows control of where these recordings are saved. By default, this is inside the current user’s Documents folder.
By default, FreeDV uses the following locations to store configuration:
On Linux, XDG_CONFIG_HOME defaults to ~/.config if not explicitly overridden. Note that if you are not running the AppImage, the behavior is different if your distro does not include wxWidgets 3.3 or newer. In those cases, the default configuration file location is ~/.freedv, which is the same as in prior versions of FreeDV.
If you’d like to store the configuration in another location (or store multiple configurations), FreeDV accepts the -f (or –config) command line arguments to provide an alternate location. An absolute path is recommended here; however, if only a relative path is provided, it will be relative to the following locations:
You can also save and restore different configuration files by using the Tools->Export Configuration and Use Configuration menu items. These menu options allow for switching of configurations without restarting FreeDV. Note that restoring a configuration file does not modify the default configuration. However, the last restored configuration file will be loaded the next time FreeDV starts, unless you choose Tools->Load Default Configuration or restore a different configuration file.
On Windows, you can create shortcuts to FreeDV with different file names for the “-f” command line option as described above. To create a shortcut, right-click on the Desktop or in File Explorer and choose New->Shortcut. Click on Browse and navigate to one of the following paths:
Click Next and give the shortcut a unique description (e.g. “FreeDV IC-7300”). Then push Finish to create the shortcut.
Once the shortcut has been created, right-click it and choose Properties. Find the Shortcut tab in the resulting dialog box and add “-f” followed by the desired filename to the end of the text in the Target field. Do not add any other quote marks.
For example, to use a file called IC7300.conf stored in the Hamradio directory on the C drive the Target field should appear as follows:
“C:\Program Files\FreeDV [version]\bin\freedv.exe” -f C:\Hamradio\IC7300.conf
FreeDV has the ability to send FreeDV signal reports to various online spotting services by enabling the option in Settings-Edit Settings (in the Reporting tab) and specifying your callsign and Maidenhead grid square. When enabled, this causes FreeDV to disable the free form Txt Msg field and only transmit the Callsign field. As this uses a different encoding format from the free-form text field, both sides of the contact must have this enabled for the contact to be reported.
FreeDV validates the received information before submitting a position report. This is to ensure that FreeDV does not report invalid callsigns to the service (e.g. ones that don’t exist or that correspond to real non-FreeDV users). However, if the reporting function is disabled, all received text will display in the main window even if it has errors.
The following services are currently supported and can be individually enabled or disabled along with the reporting feature as a whole:
The frequency that FreeDV reports is set by changing the “Report Frequency” drop down box in the main window. This is either in kilohertz (kHz) or megahertz (MHz) (configurable by going to Settings->Edit Settings->Rig Control and checking or unchecking “Frequency entry in kHz”) and will turn red if the entered value is invalid. If Hamlib support is also enabled, this frequency will automatically remain in sync with the current VFO on the radio (i.e. if the frequency is changed in the application, the radio will also change its frequency). Double-clicking on users in the Tools->FreeDV Reporter window will also cause this frequency to change to match the other user.
Note: in some setups (such as when using ALE), it is not preferred to have the reporting frequency automatically be in sync with the radio. For example, in the case of ALE, the radio’s frequency changes multiple times per second while waiting for a contact, which is faster than FreeDV can pull the latest from the radio (every five seconds). This can be disabled by enabling “Manual Frequency Reporting” in Settings->Edit Settings.
The FreeDV Reporter window includes a Message: field that allows you to broadcast a short status message (such as your location, antenna, or current activity) to other FreeDV Reporter users. Type a message and click Send to broadcast it, or Clear to remove the current message.
Note: messages are only broadcast when reporting is enabled in Settings->Edit Settings->Reporting and the Reporting toggle button in the main window is on.
Messages are not saved automatically. To save a message for later reuse, right-click the Send button to open a context menu with the following options:
Saved messages are kept in a drop-down list of up to 15 entries, sorted alphabetically. Click the arrow on the Message: field to view and select from saved messages. Right-clicking on any entry in the list opens a context menu with options to:
FreeDV will also show the callsigns of previously received signals. To view those, click on the arrow next to the last received callsign at the bottom of the window. These are in descending order by time of receipt (i.e. the most recently received callsign will appear at the top of the list).
FreeDV supports integration with external logging utilities that support the WSJT-X logging protocol (for example, KLog. This can be enabled by going to Settings->Edit Settings->Reporting and enabling the “Enable QSO Logging” option. By default, it sends packets to “localhost” (127.0.0.1) port 2237, but this can be changed if the logging computer is elsewhere on the network.
Once FreeDV decodes a callsign, it will appear in the drop-down list on the bottom of the main window. To log this contact (or any other contact received by the application), simply choose that callsign from the list and click the “Log QSO” button on the left side of the window. You will then see a dialog box that will let you enter any additional information about the contact. Upon clicking the OK button, this information will be transmitted to your logging tool.
You can also log a contact if they’re using FreeDV Reporter. Simply left-click on a row in the FreeDV Reporter window and then click on the Log QSO button. This will autofill the callsign, grid square/locator and frequency from the FreeDV Reporter servers in the dialog box.
The last selected logging source (either the FreeDV Reporter window or the drop-down callsign list at the bottom of the main window) is used for auto-filling of logging data. This is to avoid confusion (for instance, if a row in the main window is selected but it’s intended to log from FreeDV Reporter instead).
FreeDV contains a built-in time-out timer (TOT) that prevents the radio from transmitting for longer than the configured period. By default, this is enabled and set to 180 seconds (3 minutes). Fifteen seconds prior to the timeout firing, a window will appear along with a beep in your configured speakers or headset to allow you to either reset the timer or finish up your transmission.
If you desire a different timeout or want to disable the TOT, you can do so by going to Settings->Edit Settings->Rig Control and changing the TOT related options in that tab.
The following table is a guide to the different modes, using analog SSB and Skype as anchors for a rough guide to audio quality:
| Mode | Min SNR | Fading | Latency | Speech Bandwidth | Speech Quality |
|---|---|---|---|---|---|
| SSB | 0 | 8/10 | low | 2600 | 5/10 |
| RADEV1 | -2 | 8/10 | medium | 8000 | 7/10 |
| Skype | - | - | medium | 8000 | 8/10 |
The Min SNR is roughly the SNR where you cannot converse without repeating yourself. The numbers above are on channels without fading (AWGN channels like VHF radio). For fading channels the minimum SNR is a few dB higher. The Fading column shows how robust the mode is to HF Fading channels, higher is more robust.
RADE is a new mode with state-of-the-art performance, it is a contraction of Radio AutoencoDEr so-named because the modulation encoding uses a Machine-Learning method where the modulation and demodulation are achieved by training on a large number of speech samples over a modelled radio channel with typical propagation disturbances in phase and amplitude as found in HF radio. The speech is synthesised using the FARGAN neural vocoder (Frame-wise Auto-Regressive GAN) where GAN is a Generative Adversarial Network).
Unlike the previous FreeDV modes which all use QPSK modulation, the RADEV1 modulation produces an analog phase-amplitude output without defined constellation points. It has been chosen as it offers a combination of high speech quality together with reduced RF bandwidth and good resistance to fading and multipath HF radio channels.
When using RADEV1, the squelch settings in the main window are ignored. Instead, FreeDV only passes decoded audio if it’s able to synchronize with the incoming signal.
This section describes features on Tools-Filter.
| Control | Description |
|---|---|
| Noise Suppression | Enable noise suppression, de-reverberation, AGC of mic signal using the Speex pre-processor |
Auto EQ (Automatic Equalization) adjusts the input speech spectrum to best fit the speech codec. It can remove annoying bass artifacts and make the codec speech easier to understand.
Bass/Mid/Treble (for both microphone and speaker) can also be adjusted here, either with the arrow keys or your mouse. A graph displaying the frequency response of the signal based on your current settings will display in this window as well.
| Control | Description |
|---|---|
| Clipping | Increases the average power. Ensure your transmitter can handle high RMS powers before using! |
| TX Band Pass Filter | Reduces TX spectrum bandwidth |
If you have an interesting test case, for example:
Please send the developers an off air recording of the signal. FreeDV can record files from your radio using Tools-Record File from Radio. A recording of 30 to 60 seconds is most useful.
With a recording we can reproduce your exact problem. If we can reproduce it we can fix it. Recordings are much more useful than anecdotes or subjective reports like “FreeDV doesn’t work”, “SSB is better”, or “On 23 December it didn’t work well on grid location XYZ”. With subjective reports problems are impossible to reproduce, cannot be fixed, and you are unlikely to get the attention of the developers.
It is possible to have multiple panes opened within the GUI window for example, to observe both the Waterfall and Spectrum Tabs. New panes may be added above, below, left or right of existing panes.
A new visible pane is created by hovering the cursor over the required Tab, click and hold the left mouse button and drag the Tab to the required position and releasing the mouse button. If currently two panes are stacked vertically a third pane may be added either beside either pane or to the left/right of both panes. If the Tab is required adjacent to both panes then it must be dragged to the left/right of the junction of the existing Tabs.
As the Tab is dragged into position a faint blue/gray image will show the position to be occupied by the pane. Panes may be relocated back to the menu bar by a similar process.
Tabs can be resized as required by hovering the cursor over the border and clicking and holding the left mouse button and dragging to required size.
By default, the tab layout is not saved. However, by enabling experimental features (see “Advanced/Developer Features”), experimental support for saving and restoring the tab layout will be enabled. This has not been well tested and may have hidden bugs or other issues.
Located on the lower left hand side of the main screen.
| Term | Notes |
|---|---|
| Bits | Number of bits demodulated |
| Errs | Number of bit errors detected |
| Resyncs | Number of times the demodulator has resynced |
| ClkOff | Estimated sample clock offset in parts per million |
| FreqOff | Estimated frequency offset in Hz |
| Sync | Sync metric |
The sample clock offset is the estimated difference between the 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.
These features were added to help diagnose sound card issues during development.
Debug FIFO and PortAudio counters: used for debugging audio problems.
The PortAudio counters (PortAudio1 and PortAudio2) should not increment when running in TX or RX, as this indicates samples are being lost by the sound driver which will lead to sync problems.
The Fifo counter outempty1 counter should not increment during TX, as this indicates FreeDV is not supplying samples fast enough to the PortAudio drivers. The results will be resyncs at the receiver.
Check these counters by pressing Start, then Reset them and observe the counters for 30 seconds.
If the PortAudio counters are incrementing on receive try:
Adjusting framesPerBuffer; try 0, 128, 256, 512, 1024.
Shut down other applications that might be using audio, such as Skype or your web browser.
A different sound card rate such as 44.1kHz instead of 48kHz.
If the outempty1 counter is incrementing on transmit try increasing the FifoSize.
The txThreadPriority checkbox reduces the priority of the main txRX thread in FreeDV which may help the sound driver thread process samples.
The txRXDumpTiming check box dumps timing information to a console. Each number is how many ms the txRXThread took to run.
The txRXDumpTiming check box dumps the number of samples free in the 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.
Settings - Edit Settings - Half Duplex check box
FreeDV GUI can operate in full duplex mode which is useful for development or listening to your own FreeDV signal as only one PC is required. Normal operation is half duplex.
TX and RX signals can be looped back via an analog connection between the sound cards.
On Linux, using the ALSA loopback module:
$ sudo modprobe snd-aloop
$ ./freedv
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)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 Settings->Edit Settings->Debugging and enable “Enable Experimental Features”. Note that if you have problems after 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!)
By default, FreeDV attempts to set the radio’s mode to DIGU/USB-D. Some radios do not support data modes and only have USB. For these, you can go to Settings->Edit Settings->Rig Control and check the “Use USB instead of DIGU” option. This will cause FreeDV to use the standard USB mode for rig control instead.
Note that for best results, your radio should have all processing disabled if you’re using the standard USB mode. This disabling of processing typically takes place when using data mode.
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 better with FreeDV. An overdriven signal will have poor SNR at the receiver.
This can be challenging the first time around:
Try a receive only (one audio card) set up first.
Ask someone who already runs FreeDV for help.
If you don’t know anyone local, ask for help on the digital voice 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. Ensure that the CI-V address in both FreeDV and on the radio are the same. If “00” is used on the FreeDV side, ensure that the “CI-V 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.
Some Linux distributions come with pre-installed software that may try to use serial ports that your radio creates. You may have problems initialising your radio or CAT control via hamlib may seem unreliable or time out.
Brltty is software that looks on serial ports for a Braille device which will also upset CAT communication with your radio. Typically this is seen as a timeout error windw from hamlib.
Stop BRLTTY as follows:
sudo systemctl stop brltty-udev.service
sudo systemctl disable brltty.service
sudo systemctl mask brltty-udev.serviceBRLTTY is the most common cause of communication problems but it’s also been reported that in some cases ModemManager can give trouble.
ModemManager is on some Ubuntu based distributions and it will try to reset a modem by sending AT commands which will upset your radio.
Stop ModemManager as follows:
sudo systemctl stop ModemManager
sudo systemctl disable ModemManager
sudo systemctl mask ModemManagerIf you’re using OmniRig and have problems getting rig control to work, please attempt to update the INI files for OmniRig. These can be 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.
There are many radios, many computers, and many sound cards. It is impossible to test them all. Many radios have intricate menus with 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.
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 Analog button will let you hear the received signal from the SSB radio.
Try the Test Wave Files above to get a feel for what a FreeDV signal looks and sounds like.
Verify audio device settings in FreeDV. If your audio settings are correct, there are a few other possibilities:
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.
Many people struggle with initial CAT control and PTT setup:
Read the “CAT/PTT Configuration” section above.
Try the “Test PTT” button inside Tools->CAT and PTT Config.
Check your rig serial settings. Did you change them from defaults for another program?
Linux version: do you have permissions for the serial port? Are
you a member of the dialout group?
Ask someone who already uses FreeDV to help.
Contact the digital voice mailing list. Be specific about your hardware, what you have tried, and the exact nature of the problem.
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 drivers used by the most common devices can be found here.
While it is preferred to use devices that use authorized/original versions of the various USB to serial chipsets, it is possible to use some cloned devices with older drivers. When doing this, you may also need to force Windows to use an older version of a driver instead of automatically updating the driver on reboot. See here for instructions on doing so in Windows 10. For Windows 8:
You may need to clean out the previous configuration. Try Tools - Restore Defaults. Set up your sound cards again with Tools - Audio Config.
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.
From January 2020 Apple is enforcing notarization for all macOS applications. While official releases of FreeDV are signed, other types of builds may not be. This may result in a dialog box similar to the below:
(or on later releases of macOS) a message indicating that the FreeDV binary is “corrupt”. To override the notarization requirement and execute FreeDV, run the following from Terminal:
xattr -d com.apple.quarantine FreeDV.appor
xattr -d -r com.apple.quarantine FreeDV.appmacOS has a longstanding issue that prevents certain audio devices from appearing. More info here.
Many Linux distributions are switching away from X11 and towards a
new GUI system known as Wayland. Wayland explicitly does not support
window positioning by applications, instead leaving it to the user’s
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.
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| Term | Notes |
|---|---|
| AWGN | Additive White Gaussian Noise - a channel with just noise and no fading (like VHF) |
| FEC | Forward Error Correction - extra bits to we send to protect the speech codec bits |
| LDPC | Low Density Parity Check Codes - a family of powerful FEC codes |
Note: Legacy FreeDV modes (700D/700E/1600) have been removed due to low use. FreeDV 2.4.x is still available if one wishes to operate these modes.
See this for more information about changes in versions prior to 2.3.0.