TII decoding uses het spectrum of the "NULL" part of the DAB frames, in the spectrum of this NULL part one can see a few elements with an amplitude larger than the others.
Decoding is by extracting these elements, and applying a mapping process that - eventually - results in a (mainId, subId) pair, identifyinf the transmitter.
The difficulty in the decoding is recognizing data and avoiding the noise. The decoder uses a threshold value to do this. The configuration window contains an element with which the threshold value can be set. The default value is 6 dB, which is rather low.
What happens if the decoder sees noise as signal is, obviously, that the decoder generates (mainId, subId) pairs that are faulty. These pairs are matched in a database to find the attributes of the transmitter. Of course, in most cases a faulty (mainId, subId) pair does not lead to the recognition of a transmitter
The configuration window contains a selector, labeled all tii, that
- when set - shows for all identified (mainId, subId) pairs a transmitter. With a decent antenna aand a low threshold value one might (and probably will) dozens of lines - like below - telling a transmitter "not in database" (Of course, if the selector is not set, the (mainId, subId) pairs for which not transmitter is found are eliminated from the output).
Qt-DAB is software for Linux, Windows, MacOS and Raspberry Pi for listening to terrestrial Digital Audio Broadcasting (DAB and DAB+).
Qt-DAB is GUI based, for a command line version, see dab-cmdline. Qt-DAB has a single main window that contains essentially all that is needed for selecting channels and services and listening to a service. Other windows, visible under user control, show a myriad of controls, and a tremendous amount of data extracted from the DAB signal and the resulting audio,
Of course, as for previous versions, for the current version, Qt-DAB-6.9.6, predefined executables and installers are available. For Linux there is an x64 AppImage, for Windows there is a single 64 bit installer, one with separate entries to select a V3 or V4 rtlsdr device.
- Introduction
- Features
- Windows and scopes
- Devices and device support
- Scan control
- Displaying TII data
- EPG Handling and time tables
- Journaline data
- Logging errors
- Documentation
- Installation on Windows
- Installation on Linux
- Notes on building an executable
- Using user specified bands
- Copyright and acknowledgements
Qt-DAB is designed to be used with a variety of SDR devices. Precompiled versions for Windows and Linux (x64) are available that support most devices for which Qt-DAB provides support (see below). Thanks to Richard Huber, Qt-DAB can be compiled on the Mac as well, though it is most likely not a trivial exercise.
- Qt-DAB supports most common SDR devices directly. The device interface is quite simple and in a different document it is explained in detail how to use the interface to implement control for other devices;
- Qt-DAB recognizes and interprets TII (Transmitter Identification Information) data of - if the received signal is from multiple transmitters - all detectable transmitters, can be made visible simultaneously, and Qt-DAB displays the transmitters on a map in a browser. A separate tool is available to download a database, the precompiled versions contain a copy of the database;
- Qt-DAB starts EPG/SPI services automatically as background task and provides means to show resulting time tables;
- Qt-DAB supports journaline, often transmitted as subservice, if a journaline (sub)service is detected, auto starts a small journaline window;
- Qt-DAB supports so-called favorites (i.e. channel, service pairs) for easy switching between services in different ensembles (see below),
- Qt-DAB allows running an arbitrary amount of audio services from the current ensemble as background service, with the output sent to a file,
- Qt-DAB supports a scanList, i.e. a list with channel/service pairs encountered. Obviously, selecting a service from this list is possible;
- Qt-DAB offers the possibility of generating an ETI file from the ensemble in the currently selected channel,
- Qt-DAB offers different views on the input data, see below,
- Qt-DAB offers the possibility of scanning through all - or a selected subset - channels of the band,
- Qt-DAB offers options to select other bands, i.e. the L-Band, or channel descriptions from a user provided file and it supports obsolete modes (Mode II and Mode IV),
- and much more ...
The main window (see picture) of Qt-DAB (always visible), contains selectors for controlling the visibility of other windows. The window shows - left half - a list of services (either from the currently selected channel or from favourites). Selecting a service is just by clicking on the name. The right half of the window shows the dynamic label, and the slides - if transmitted as part of the service - or a series of default slides.
- touching the ensemble name (NPO (8001) in the picture seen top left) makes the content table, i.e. an overview of the content of the ensemble, visible with the possibility of storing the data in a file in ".csv" format. If the content table is visible. Touching the ensemble name again will hide it;
The picture above shows the topline op the right half of the main window.
- touching the small icon left on the top of the right half will show (or hide) the technical window, a window showing all technical details as well as strength indicators and a spectrum of the audio of the selected service;
- touching the small icon to the right next, the folder/directory in which the slides, the tii log and the log file are written is shown;
- NEW: touching the small blue icon causes the device list to be displayed. Touching the icon again hides the icon. After selecting a device, the device list will be hidden as well.
- touching the icon showing a speaker controls muting the signal and shows whether or not a signal should be audible.
- touching the copyright symbol shows (or, if visible, hides) a small about window with acknowledgements for using external libraries;
At the bottom of the right half of the window, one sees the buttons shown above, from right to left:
- the button labeled scan controls the visibility of a the scan handler window;
- the button labeled *http controls the http handler with which a browser is started that shows a map (with the transmitters displayed on their location). NEW is that closing the http handler closes the browser as well (depending on a setting in the configuration window);
- the button labeled spectrum controls the visibility of the spectrum window, a window with options to select among different views on and information of the DAB signal itself;
- the button labeled controls controls the visibility of the so-called configuration and control window, a window that provides numerous settings for this software;
The bottom line in the picture above shows the transmitter name from the transmitter with the strongest data, and - in this case - that the avx2 instruction extension is used for some computations. (Qt-DAB comes in two versions, one with support for the avx2 instructionset, and one without). Clicking on that bottom line controls the visibility of the dxDisplay (see below).
The picture below shows (part of) the left half of the main window. It shows a list of services, and - at the bottom - a few buttons and selectors.
- the buttons labeled "+" and "-" can be used to scan through the list of services;
- the up- and down arrow can be used to scan through the channels, a channel can be selected by touching an element of the combobox;
- the button labeled favourites controls whether the list of services from the currently selected channel or the list of favourites is shown,
- the button labeled scanlist controls the visibility of the scan list, i.e the list of all services seen, shown below.
(Obviously, the colors of the buttons, as well as the font, the font size and the font color of the service list shown can be set by the user, just click with the right hand mouse button on a button).
As mentioned, Qt-DAB supports favorites, i.e. a list of (channel, service pairs). The list is maintained between program invocations. The services widget on the main window is shown in one of two modes, selectable by the button (in the picture labeled) favourites. In ensemble view mode, the services in the current ensemble are shown, in the favourites view mode, the favourites are shown.
In both views, selecting a service is just by clicking on the service name. Of course, when selecting a service in the list of favourites, it might take a few seconds before the software has switched over to the appropriate channel, and has received sufficient information on the new ensemble carried in that channel before being able to select the service in that channel.
Adding a service to the favourites is by clicking on the field in the right hand column, shown in the services list. If - in ensemble mode view - a service is also part of the favourites, the field in the right hand column shows a mark. Clicking on such a mark removes the service from the list, as does clicking on the field in the favourites view*.
The technical window shows - as the name suggests - technical details of the selected audio service. If the audio of the service is also transmitted on FM, the FM frequency (frequencies) - derived from additional data in the DAB datastream - is shown as well.
The buttons at the top of the window control dumping the audio (".wav" file) resp. the AAC or MP2 frames into a file. AAC amd MP2 encoded files can be processed by e.g. VLC.
The timeTable button has only effect if on this channel (ensemble) an EPG service is or was active. Data from the EPG service is stored, and the timetable is an interpretation of that data.
Below the timeTable button the static (meta)data of the selected audioservice is shown.
The three progress bars (quality indicators) for DAB+ give success rates of resp. detecting a DAB+ frame, the RS error repair and the AAC decoding. (For "old" DAB transmissions only a single quality indicator appears).
Below the progress bars the rsCorrections/100 indicator shows how the amount of corrections that was made by the Reed-Solomon detector in the last 100 AAC frames (only used for DAB+ services). Of course, the parity bits used by the RS decoding may contain bit errors themselves, which mot likely lead to CRC errors, the second indicator shows the amount of CRC errors detected after the correction by the RS decoding.
The third indicator tells the percentage of the AAC (or MP2) data that was found to be OK.
The scope at the bottom shows the spectrum of the audio.
As mentioned above, a spectrum window can be made visible by clicking on a button on the main window. That window is equipped with a tab for selecting one of 6 views on the input signal.
In the view shown in the picture above, the spectrum of the incomin DAB signal is shown. To the right of this spectrum, one sees the signal constellation, i.e. the mapping from the complex signals onto their real and imaginary components. If the selector labeled "ncp" is set, the centerpoints of the 4 lobs is shown.
Below this constellation widget, some quality indicators of the DAB signal are shown. From top to bottom
- the channel and the frequency of the channel
- the correction, i.e. the computed correction on the frequency of the incoming signal that is applied to the signal;
- the freq error, i.e. the remaining frequency error (in Hz) after applying the correction;
- the SNR, i.e. the Signal-Noise Ratio in dB;
- the time offset, the (relative) resulting error in sampling;
- the clock offset, telling the number of samples too much or too little in the duration of 10 DAB frames;
- the IQ unbalance, i.e. the (average) difference in strength between the I and the Q part of the DAB signal.
At the bottom of the window from left to right
- a sync indicator, when green indicating that the software is synchronized with the incoming sample stream;
- a FIC indicator, telling the (average) successrate of decoding the FIC part of the DAB frames (i.e. the data that specifies the payload);
- a BER, Bit Error Rate, telling (on average) how many input bits were wrong (and were corrected), per 1000 input bits (here 1 per 100, lower is better);;
- a MER, Modulation Error Rate, indicating the quality of the input signal (higher is better);
The ideal form of the spectrum and the signal constellation as shown in the picture above is not often seen with real inputs.
The correlation scope shows the correlation between the incoming signal and predefined data, i.e. the data as they should be. Correlation is used to identify the input sample in the input stream where the (relevant) data of the frame starts. The picture shows three larger peaks, i.e. the signal from more than one transmitter is received. The software chooses either the largest one, or - if selected - the first one larger than a threshold. The picture shows an estimate of the TII numbers near the peaks, it shows that "(4, 21) Alphen aan den Rijn/Celinex toren" gives the strongest signal/
A DAB signal is received as a sequence of samples, and can be thought to be built up from frames (DAB frames) where each frame consists of 199608 consecutive samples. The amplitude of the first app. 2500 samples is (almost) zero, the NULL period. The NULL scope shows the samples in the transition from the NULL part to the first samples with data of a DAB frame. It shows that samples 504 and up in the first data block are used.
In reality the NULL period is - in most cases - not completely without signal, each second **NULL period ** may contain an encoding of the TII (Transmitter Identification Information) data. The TII scope shows a condensed form if the spectrum of the data in the relevant NULL period, the TII data is encoded as a 4 out of 8 code. Indeed, four larger (and four smaller) peaks can be seen in the picture. In this picture the pattern shown is 0x1e.
The DAB definition provides tables to map the recognized patterm to a two 2 digit number, the latter is used to identify the transmitter in a database, available in Qt-DAB.
The picture shows the channel response on the amplitude, and the red line, i.e. the channel effects on the phase of the samples. The picture clearly shows two larger and a few smaller peaks.
The deviation scope shows the mean deviation of the carriers in the decoded signal, ideally their phase is (a multiple of) 90 degrees. The phases are mapped upon (soft) bits, the larger the deviations, the less reliable these bits are. The Y-axis is in Hz.
The configuration and control window contains checkboxes, spinboxes and buttons with which the configuration of the decoding process can be influenced.
NEW is the selector clear on exit. If enabled, the scanlist is cleared on program exit.
Also new is the selector local DB. If enabled on program startup Qt-DAB will load an embedded TII database, rather than trying to load a TII database from the user's home directory.
Finally, also new is the selector map close. If enabled, closing the map as sketched before is enabled.
Slightly experimental is the possibility to save titles (parts of the dynamic labels) of (mostly) songs that are transmitted. This is by interpreting the so-called DL2 data, note that not all ensembles send DL2 data. The selector labeled save titles controls this, the titles - see picture above - are stored in a file DL2_titles.csv in the Qt-DAB-files directory.
Just as a gadget, the window contains an indicator for the CPU load. This load is the overall CPU load, not only the load from running Qt-DAB. Furthermore, the indicator, left of the CPU load text, here with value 1, tells how many backends are active simultaneously.
For a detailed description of all selectors, see the manual (or read the tooltips).
In the current set up, Qt-DAB supports 6 types of (physical) input devices, some network input, and file input:
- DABsticks (RTL2838U or similar), with separate libraries for the V3 and V4 versions of the stick in the precompiled Windows versions;
- All SDRplay SDR models (RSP I, RSP 1A and 1B, RSP II, RSP Duo, RSP Dx and RSPDxR2), with separate entries for the v2 and v3 library. New is extended support for the SDRPlay RspDuo. Tuner selection (and tuner 2 is connected to a port with biasT support) is now operational;
- a special entry exists for the SDRplay RSPDuo, one for running both tuners simultaneously;
- HACKRF One;
- Airspy, including Airspy mini (be aware that AirspyHF is not able to provide the samplerate required for DAB);
- LimeSDR;
- Adalm Pluto;
- untested UHD (anyone wants to help testing?).
Apart from the untested UHD device, support for these 6 device types is commonly included in the precompiled versions. It was noted by users that when using the support library for the V4 version of the RTLSDR (aka DABsticks) devices with V3 devices the software seemed rather deaf. To accommodate that, there are two device entries, one supporting the V3 versions of the DAB sticks, the other for the V4 versions.
In Qt-DAB the approach is to dynamically load the functions from the manufacturer's device library as soon as a device is selected (and not sooner). This approach allows distributing versions that are configured with devices not installed on the user's system.
For the Windows version(s), the device libraries for almost all configured devices are provided in the installer. The exception are the SDRplay and Pluto devices. For SDRplay devices the user has to install the drivers from the SDRplay site, for Pluto support one should see the instructions in "https://github.com/analogdevicesinc/plutosdr-m2k-drivers-win". For Linux users, Ubuntu provides the required libraries in a repository (i.e. libii0 and libad9361, for e.g. Fedora the support seems to stop at F33.
Qt-DAB also supports input using a network:
- an rtl_tcp server connected to an RTLSDR device.
- a spyServer (both 8 bit and a 16 bit version), i.e. from AIRSpy devices and RTLSDR devices.
Be aware that Qt-DAB processes the input with 2048000 Samples/second. Using the 16 bit version of the spyServer - 4 bytes per sample - requires a bandwidth of at least 8 M. I am the 8 bit version of the spyServer, as well as the rtl_tcp server using it with a wired connection between two laptops, using the WiFi is not very successful.
Note that - as the control window suggests - it is possible to "dump" the unprocessed input to an xml type file (as can be seen on the control picture, the selected samplerate is 2500000).
Qt-DAB furthermore supports
- Soapy (Linux only, not included in the AppImage), a renewed Soapy interface driver is even able to handle other samplerates than the required 2048000 (limited to the range 2000000 .. 4000000).
Qt-DAB obviously supports:
- reading (and writing) ".sdr" type files from the input, where ".sdr" type is a form of ".wav" file with IQ samples with fixed inputrate 2048000. Qt-DAB generates such files. NEW is the ability of Qt-DAB to generate this type of file with a size larger than 4 Gb, their type is BW64. Obviously Qt-DAB has the ability to read such files back.
The device window gives information on the "type" of the file i.e. RIFF or BW64. When reading input from an ".sdr" file that was generated by Qt-DAB both the name of the SDR device as well as the channel frequency of the reception is displayed as shown in the pictures above.
-
reading prerecorded dump rtlsdr type "raw" (8 bits) files. The RTLSDR device handlers show a button "dump" for dumping the raw input into a ".raw" file.
-
reading (and writing) so-called "xml" files, i.e. a file format preserving the precise structure of the input samples. All device handlers show on their device window a button to control dumping the unmodified input into an xml file (e.g. for the Airspy this means with a samplerate of 25000000 or 3000000).
A separate window - visible under control of the scan button on the main window - provides full control on scanning. Qt-DAB provides different scanning modes: scan to data, single scan and scan continuously.
- With single scan, i.e. a (single) scan over the channels of the band, a listing is produced of (the contents of) all ensembled encountered. In the scan window the channels where data was found, and the transmitters found for these channels, are given, as shown in the above picture.
- With scan to data scanning starts and continues until a channel is detected that carries DAB data (or scanning is stopped by touching the stop button).
- With scan continuously, i.e. scanning until stopped by the user, a single line is shown for each ensemble encountered, and - as the name suggests - scanning goes on until stopped by the user.
To allow skipping given channels when scanning, Qt-DAB supports the notion of a scantable, a table in which channels can be marked for skipping. Next to a default scantable - which is stored in the users ".ini" file, scantables can be created as separate files and read-in when required.
The show button controls the visibility of the scantable, scantables can be loaded and stored in either the ".ini" file (use the "...default" buttons, or can be kept as xml file on a user defined place (the other load/store buttons).
The table at the bottom of the window is just for convenience, on scanning it displays the channel name being scanned currently, the ensemble name encountered and the number of services detected in the ensemble. Only for scan single the transmitters that were identified are shown as well.
As mentioned, transmitters (usually) transmit some identifying data, the TII (Transmitter Identification Information) data. Qt-DAB uses a database (gratefully made available by "www.fmList.org") to map the decoded TII data to name and location of the transmitter.
In recent versions, a copy of that database is part of the precompiled versions. The configuration and control window contains selector that by default is set "on", meaning that on program startup that database is used. A fresh copy of that database can be installed in the user's home directory by a small utility, a db-loader, precompiled for Windows and Linux-x64. The db-loader installs the database, file ".txdata.ti" in the user's home directory, that is where Qt-DAB expects a database - with that name - to be found. The configuration and control window contains a button to load the database from the user's home directory into the program.
Alternatively (and for other computing environments) one can download a reasonably up to date copy of the database from the directory helpers in the Qt-DAB repository. Unpack the zipped file "tiiFile.zip" and name it ".txdata.tii" in the home directory.
As was shown earlier, one usually receives signals from more than one transmitter. While the line at the bottom on the right half of the Qt-DAB's main window always shows the strongest transmitter, Qt-DAB can also show data of all identified transmitters on a small separate window (if selected), the dxDisplay.
The picture shows that the ensemble, transmitted in channel 12C is "NPO", and it shows for each of the identified transmitters some data. The first column shows a mark for the strongest transmitter, the pattern is shown as well as the TII values (the mainId, and the subId) of the identified transmitters. Furthermore, the azimuth from and the distance to my home location, the power of the transmitter, the altitude (we are in a low-laying part of the country), and the height of the transmitting antenna.
The compass shows the direction of the signal from the strongest transmitter.
Qt-DAB has as said - on the main window - a button labeled http, when touched, a webserver is started with on it a map centered around the home position, that - when running - shows the position(s) of the transmitter(s) received. (Note that since recently, Qt-DAB contains a default home location - somewhere in Amsterdam - that - together with default database - allows the software to handle TII data and show the result of decoding on a map). It is advised to update the user's home location, the configuration and control window contains a button coordinates that when touched, shows a small menu where latitude and longitude can be filled in).
The picture shows the channels I receive with a simple whip next to my "lazy chair". Of course, using a more advanced antenna. more transmitters show, as seen on the picture below (courtesy of Herman Wijnants)
The webbrowser listens to port 8080. By default, the "standard" browser on the system is activated. The configuration and control window contains selector changing the port as well as turning the automatic activation off.
NEW is that on closing the http handler and if on the configuration window the checkbix map close is selected, the webbrowser closes. If one closes the webbrowser, the - the other way around - the http handler is closed.
While not here in the Netherlands, in many other countries an ensemble contains an EPG or SPI service. Such a service contains data for service logo's and for time tables. If such a service is detected within a handful of seconds after the start of the channel, Qt-DAB will attempt to start the service as background task. If the EPG/SPI service was identified late, the service can be started manually and will also run as background task.
Data decoded by this service will be stored in a separate directory that is itself stored in the user's Qt-DAB-files directory.
If sufficient data is read in that directory, the software might find a service logo and a time table for the selected service. The logo - if found - is shown on the main window (picture above) next to the service name. The time table - if found - is made visible by touching the timeTable button on the technical window.
If no data for the time table is found, the time table will say so
The timeTable window contains a next and prev button to scan through different dates. Older pages are not removed by default, selecting a page and touching the "remove" button will remove the currently selected page.
While not in the region where I live, in some countries (Germany) DAB services are sometimes augmented with Journaline data. This data is - at least in the examples I have - transmitted in a subservice as shown in the picture Qt-DAB uses the NewsService Journaline (R) Decoder software from Fraunhofer IIS Erlangen in a slightly modified form (all rights gratefully acknowledged).
(Categorie names with an asterisks attatched show that new data is available)
Reporting of errors is now done in a (more or less) systematic way. Especially errors with devices (I often get error messages when setting gain values in my SDRplay equipment), such as a device that does not start properly.
While Linux is essentially command line based and error messages are - usually -printed on the command window, the command window in the precompiled Windows versions is always switched off and error messages are "lost".
A class was added to save error messages. These messages are written into a file with the name errorlog.txt, in the directory (folder if you wish) Qt-DAB-files, in the user's home directory.
Error messages take the form
- dabstick at 2025-09-01T13:35:00 -> No rtlsdr device found
i.e, an entity (usually a device name) in which the error occurred, the date and the error message itself.
Most selectors on the various windows have a tool-tip that explains theur function.
An introductory text, covering the regular use is available and includes in the latest release.
For Windows an installer can be found in the releases section of this repository
Currently, there are two versions, one with the name ending in -scalar, the other one with the name ending in -avx. As mesntioned earlier, the suffix tells whether or not avx2 instructions are used in some of the computations or not. Older CPU's do not support these instructions.
The installer will install the executable as well as required libraries, although for both SDRplay devices (when used) or for the Adam Pluto (when used), one has to install libraries from the provider of the device (see below).
For Linux-x64 systems, an appImage can be found in the releases section of this repository
As for Windows, two versions are available, one with and one without use of avx2 instructions.
The appImage contains next to the executable Qt-DAB program, the required interface libraries but not the support libraries for the configured devices. If you want to use a physical device - e.g. a DABstick, an SDRplay, or an AIRspy you need to install the driver libraries for the device as well.
For using an SDRplay device one should download the - proprietary - driver software from the SDRplay site. Note that while Qt-DAB has a device entry for the "old" 2.13 library, that library does not support the newer SDRPlay device model such as the SDRPlay 1B, the SDRplayDx and the SDRPlay Dx-II. Use the 3.XX library instead. The libraries can be found on the website of SDRplay
For using an AIRspy or a Hackrf device the Windows Installers contain support libraries. For Linux, the Ubuntu (and bullseye repository for the RPI) the repository contains appropriate software.
For using an RTLSDR device the Windows Installers contain support libraries. For Linux, the Ubuntu (and bullseye) repositories do provide a package. However, using that package one needs the kernel module to be blacklisted, see e.g.
Personally, I prefer to build a version of the library myself, installation is easy, see:
For using the LimeSDR device the Windows Installers contain support libraries. For Linux I went back to the sources and compiled the support library myself, see:
For installing the support software for the Adalm Pluto for both Windows and Linux I followed the instructions on
Note that Ubuntu releases provide libraries for supporting the Pluto.
It is strongly advised to use qmake/make for the compilation process, the qt-dab-6.9.pro file contains (much) more configuration options than the CMakeLists.txt file that is used when using cmake.
Note that the scheme presented below is applied when building the AppImage on Ubuntu 22, and was tested on the "bullseye" system on the RPI. For other distributions (or later Ubuntu versions), names of library packages may be different. Note that in all cases, the development versions (i.e. the versions with the include (".h") files) are required.
For creating an executable on and for Windows the easiest approach is to install msys/mingw and follow the process as sketched (I use Mingw64 packages on Fedora to cross-compile). Using an MS toolchain on Windows was for me (I tried it once) not successfull and, since I develop compile and cross compile on a Fedora Linux box, my interest in developing ON windows is less than zero.
- ℹ️ In the repository, the sources for the current Qt-DAB version (6.9.3) are in the directory "qt-dab/ sources". All sources and include files are found in this directory". The ".pro" file is - as is the CMakeLists.txt file - in the "qt-dab" directory. The qt-dab repository contains a file "structure.md" in which the structure is explained.
Running with the ".pro" file as in the repository , the resulting Qt-DAB executable is stored in a directory "/linux-bin" when compiled for Linux and in a directory "/usr/shared/w32-programs/windows-dab32-qt" when compiling for windows (using mingw64). You probably want to modify it.
For building the AppImage on Ubuntu 20, I load the required libraries as given below:
- sudo apt-get update
- sudo apt-get install git
- sudo apt-get install cmake
- sudo apt-get install qmake6
- sudo apt-get install build-essential
- sudo apt-get install g++
- sudo apt-get install pkg-config
- sudo apt-get install libfftw3-dev
- sudo apt-get install portaudio19-dev
- sudo apt-get install zlib1g-dev
- sudo apt-get install libusb-1.0-0-dev
- sudo apt-get install mesa-common-dev
- sudo apt-get install qt6-base-dev
- sudo apt-get install qt6-multimedia-dev
- sudo apt-get install libcurl4-openssl-dev
- sudo apt-get install libfdk-aac-dev (read the note below)
- ℹ️ An issue is getting the required qet library. On my Fedora box, a qwt-6.2 version for Qt6 is available, Ubuntu does not provide the Qt6 version for qwt. I had to install it myself
- Download qwt-6.30 from "https://sourceforge.net/projects/qwt/files/qwt/6.3.0/";
- follow the instructions (i.e. unzip, cd to the unzipped folder) and adapt the config file to your likings;
- building is then simple (takes some time though): "qmake6 qwt.pro", "make";
- install the library ("sudo make install") and inform the loader "sudo ldconfig";
- Note that the default for installation is "/usr/local/qwt/6.3.0", adjust the PATH settings accordingly.
- ℹ️ While the libfdk-aac-dev package in both Fedora and Ubuntu 24 seems to work fine, I had some problems with the package from the repository in Ubuntu 20 and 22. For the AppImage, built on Ubuntu 20, a library version was created from the sources to be found as github repository:
The sources contain a CMakeLists.txt file, building and installing is straightforward.
Alternatively, one could configure for libfaad, change the configuration to
- CONFIG += faad
- #CONFIG += fdk-aac
and install the libfaad package
- sudo apt-get install libfaad-dev
- ℹ️ If "soapy" is configured, libsamplerate (both the library and the include files) should be installed on the development system. Of course the various Soapy libraries as well.
While there are dozens of configuration options, take note of the following ones:
-
ℹ️ A new viterbi decoder is part of the sources, one may choose between this "new" one and the "older" version derived from the spiral project.
CONFIG += viterbi-scalar #CONFIG += viterbi-sse #CONFIG += viterbi-avx2 #CONFIG += spiral-sse #CONFIG += spiral-no-sse
If unsure, choose either "viterbi-scalar" or "spiral-no-sse"
Default is using a scalar version of the viterbi decoder, which works just fine, though requires more CPU time.
-
ℹ️ Qt-DAB can be compiled with floating numbers as "floats" or as "doubles"
CONFIG += single
CONFIG += double.
In the latter case, all computations in the "front end" are done with double precision arithmetic.
-
ℹ️ Devices like SDRplay, AIRspy, RTLSDR dongle, LimeSDR, HackRf and Adalm Pluto can be included in the configuration even if no support library is installed. (Note that including Soapy requires Soapy libraries to be installed, so this does not apply for Soapy). Qt-DAB is designed such that on selecting a device in runtime, the required functions from the device library are linked in.
-
ℹ️ The Soapy library used in Ubuntu 20 (used for building the AppImage) seems incompatible with Soapy libraries installed on other versions of Ubuntu and other Linux distributions, therefore Soapy is NOT configured for inclusion in the AppImage.
-
ℹ️ Uncomment the line DEFINES += __THREADED_BACKEND if you intend to have more than one backend running simultaneously. E.g. activating the automatic search for an EPG service starts a separate service if such a service is found. With this setting each backend will run in its own thread.
Run qmake (variants of the name are qmake6, qt6-qmake, etc) which generates a Makefile and then run make. Compiling may take some time. Use make -j XX for speeding up the build process, with XX the amount of parallel threads used. Of course, qmake will complain if not all required libraries can be found. If all libraries were found, this step should result in an executable.
Use the database downloader (for Windows and Linux available as precompiled item) to download a fresh copy of the database. Or download a copy of the database from the repository.
A copy of the database is part of the repository. The directory helpers contains a file "tiiFile.zip", unpack the zipped file and store the result in your homedirectory (folder).
If Qt-DAB does not see the database, it will just function without mapping TII data onto names and locations.
A user compiled Qt-DAB-6.9, on and for an RPI, and met the following issues:
Once I had downloaded the qt-dab-master from the code page, installed all the libraries listed in the Readme on the code page, and then installed the new qwt 6.30 as instructed, I had a problem getting the .pro file to recognise the new qwt version. This was because on the pi it installs to /usr/include.
So I changed the .pro file as follows:
Line 433
INCLUDEPATH += /usr/include
!mac {
INCLUDEPATH += /usr/include/qwt-6.3.0/lib
#correct this for the correct path to the qwt6 library on your system
#LIBS += -lqwt
equals (QT_MAJOR_VERSION, 6) {
LIBS += -lqwt-qt6
}else{ LIBS += -lqwt-qt5
However I still could not get the qwt recognised so further changes were needed, this time to the Modules folder.
To do this, I went to the qt-dab-6.9 folder in the qt-dab-master, and then opened the folder cmake. Then Modules. Found the relevant FindQwt file and made the following changes:
find_path(QWT_INCLUDE_DIRS
NAMES qwt_global.h
HINTS
${CMAKE_INSTALL_PREFIX}/include/qwt
${CMAKE_INSTALL_PREFIX}/include/qwt-qt6
PATHS
/usr/local/include/qwt-qt6
/usr/local/include/qwt
/usr/include/qwt6
/usr/include/qwt6-qt6
/usr/include/qt6/qwt
/opt/local/include/qwt
/usr/include/qwt-6.3.0
/sw/include/qwt
/usr/local/lib/qwt.framework/Headers
/usr/local/lib/qwt-qt5/lib/framework/Headers
/usr/include/qwt-6.3.0/include
)
if (APPLE)
set(CMAKE_FIND_LIBRARY_SUFFIXES " " " .dylib" ".so" ".a ")
endif (APPLE)
find_library (QWT_LIBRARIES
NAMES qwt6 qwt6-qt6 qwt-qt6 qwt
HINTS
${CMAKE_INSTALL_PREFIX}/lib
${CMAKE_INSTALL_PREFIX}/lib64
PATHS
/usr/local/lib
/usr/lib
/opt/local/lib
/sw/lib
/usr/local/lib/qwt.framework
/usr/local/lib/qwt-qt6/lib/framework
/usr/include/qwt-6.3.0/lib
)
With these settings Qt-DAB could be compiled
While it is known that the DAB transmissions are now all in Band III, there might be situations where it is desirable to use other frequencies. Qt-DAB provides (Unix/Linux builds only) the opportunity to specify one's own band. Specify in a file a list of channels, e.g.
one 227360
two 220352
three 1294000
four 252650
and pass the file on program start-up with the -A command line switch. The channel name is just any identifier, the channel frequency is given in kHz. Your SDR device obviously has to support the frequencies for these channels.
Copyright (C) 2016 .. 2025
Jan van Katwijk ([email protected])
Lazy Chair Computing
Copyright of libraries used - Qt, qwt, fftw, portaudio,
libusb-1, libfaad, libfdk-aac, - is gratefully acknowledged.
In developing Qt-DAB many people have contributed, special thanks
to
* Herman Wijnants,
* Andreas Mikula,
* and Jarod Middelman
for continuous feedback and suggestions, and
* Rolf Zerr (aka old-dab),
* Stefan Poeschel,
for important code contributions.
Qt-DAB is distributed under the GPL V2 library, in the hope that
it will be useful, but WITHOUT ANY WARRANTY; without even the
implied warranty of MERCHANTABILITY or FITNESS FOR A
PARTICULAR PURPOSE. See the GNU General Public License for
more details.