Qt-DAB-4.3 is software for Linux, Windows and Raspberry Pi for listening to terrestrial Digital Audio Broadcasting (DAB and DAB+). Qt-DAB is accompanied by its little sister dabMini, built on the same set of sources.
Qt-DAB-4.3 adds as configuration option, the option to show the name of the Tranmitter whose TII (Transmitter Identification Information) as well as the distance of the receiver to that transmitter and the azimuth.
Note that the documentation is NOT updated, and since I do not have time right now, it will take some time before this README and the manual are updated
Important changes are a. if configured, touching the button "load table" on the configuration widget will load - as the name suggests - a table with TII data b. Touch the button "coordinates" on the configuation window to tell the system what the coordinates - decimal, i.e 52.0123 and 5.0456 - of the receiver are.
If configured, the main widget will show the name of the transmitter, the distance and the azimuth as the pictures above show.
Configuration issues a. the build process using CMake does NOT support the configuration settings required for supporting the TII data b. using qmake:
- install curl and its development files;
- uncomment "loadTables" in the ".pro" file and adapt the paths in the
loadTables section
NOTE THAT THE AUTOMATICALLY GENERATED APPIMAGE HAS NO SUPPORT FOR SHOWING TII NAMES, USE THE ONE WITH THE 4.3 IN ITS NAME
- Introduction
- Features
- Widgets and scopes
- dabMini and duoreceiver
- Documentation
- Presets
- Saving gain settings-
- Colors
- configuration settings
- Scanning and the skip table
- Saving synamic label texts
- Scheduling option
- Obsolete properties
- Installation on Windows
- Installation on Linux x64
- Interfacing to another device
- Using user-specified bands
- xml-files and support
- EPG-Handling
- Recording the SNR
- Pluto device and fm transmission
- Copyright
Qt-DAB-4.2 is a rich implementation of a DAB decoder for use on Linux and Windows based PC's, including some ARM based boards, such as the Raspberry PI 2 and up.
4.2 differs in details from 4.1, apart from some technical changes (hopefully not seen by users), changes are that some settings are moved from the configuration widget to the widget the settings refers to. New is a "logger" setting on the configuration widget that well store -when set - some information on a file.
It provides an abundant amount of selectors and displays, most of which can be switched off, but are of interest for those who want to see aspects of the DAB signal and want to be in control.
While it is not very complicated to generate an executable for either Qt-DAB or dabMini, for Linux-x64 appImages exist for both Qt-DAB and dabMini. For Windows installers are available.
Qt-DAB makes extensive use of a GUI. Personally, grown up in the time of ASR-33 terminals and "command lines", I sometimes prefer a simple command line over a GUI. Therefore, a terminal-DAB-xxx version was developed, a simpler version, just for listening to a DAB service, making use of the command line and curses library.
For those who are nostalgic to the era and the sound of nice wooden radios with glowing tubes, Qt-DAB can be configured such that - using the Adalm Pluto as device - the audio of audio services is transmitted in FM stereo on a user specified frequency with the "dynamic label" sent as RDS.
- DAB (mp2) and DAB+ (HE-AAC v1, HE-AAC v2 and LC-AAC) decoding
- MOT SlideShow (SLS)
- Dynamic Label (DLS) and the possibility of saving dynamic Labels - augmented with channel and time info - in a file,
- Both DAB bands (and user defined bands) are supported:
- VHF Band III (default),
- L-Band (obsolete now),
- a user defined Band
- Modes I, II and IV (Mode I default, Modes II and IV obsolete, but can be set in the ".ini" file,
- Views on the signal: spectrum view incl. constellation diagram, correlation result, TII spectrum and the SNR over time,
- Detailed information on reception and selected service (SNR, bitrate, frequency, ensemble name, ensemble ID, subchannel ID, used CUs, protection level, CPU usage, program type, language, alternative FM frequency if available, 4 quality bars),
- Detailed information for other services by right-clicking on their name (bitrate, subchannel ID, used CU's protection level, program type) in the service list,
- Automatic display of TII (Transmitter Identification Information) data when transmitted,
- Presets for easy switching of programs in different ensembles (see section Presets),
- Dumping of the input data of the DAB channel (Warning: produces large raw files!) into * sdr files or xml file formats and playing them again later (see section on xml format),
- Saving audio as uncompressed wave files,
- Saving aac frames from DAB+ services for processing by e.g. VLC,
- Saving the ensemble content description: audio and data streams, including almost all technical data) into a text file readable by e.g LibreOfficeCalc
- Advanced scanning function (scan the band, show the results on the screen and save a detailed description of the services found in a file),
- ip output: when configured the ip data - if selected - is sent to a specificied ip address (default: 127.0.0.1:8888),
- TPEG output: when configured the data is sent to a specified ip address,
- EPG detection and building up a time table,
- Supports configuration as input device:
- Adalm Pluto,
- SDR DAB sticks (RTL2838U or similar),
- HACKRF One,
- Airspy, including Airspy mini,
- SDRplay (RSP I, RSP II, RSP Duo and RSP Dx), with separate entries for v2 and v3 library
- limeSDR,
- Soapy (experimental, Linux only),
- ExtIO (expertimental, Windows only),
- rtl_tcp servers.
- Always supported input from:
- prerecorded dump (*.raw, *.iq and *.sdr),
- xml format files.
- Clean device interface, easy to add other devices, see below.
- Scheduling the start of channel:service pairs or operations as frame dump or audio dump, even for days ahead
Not yet or partly implemented:
- DMB (Audio and Video)
- TPEG: when configured, TPEG messages are being sent to a TCP port; sources for a simple client are part of the source distribution.
- Journaline (an untested Journaline implementation is part of the sources).
- Other bands than used for terrestrial broadcasting in Europe (like DAB over cable)
Note: While the 2.13 support for SDRplay devices is able to handle the RSP 1, RSP II, RSP Ia and RSP duo, the 3.0X support handles all SDRplay RSP's. It is recommended to use the 3.0X support library.
Qt-DAB always shows a main widget; a number of optional widgets is visible under user control. The while set of widgets is shown below
The buttons and other controls on the main widget are equipped with tool tips briefly explaining the (in most cases obvious) function of the element (the tooltip on the copyright label shows (a.o) the date the executable was generated.)
The elements in the left part of the widget, below the list of services, are concerned with selecting a channel and a service. To ease operation the channel selector is augmented with a "-" and a "+" button for selecting the previous resp. next channel.
To ease selection of a service, a second pair of "-" and "+" buttons is available, now for selecting the previous resp. the next service on the list.
Some general data is displayed on the top right part of the widget, such as run time and current time, frequency offset and (overall) processor load (note that the "current time" is extracted from the DAB data, playing a recorded transmission shows the time of the transmission).
In the middle part, name of the ensemble and name of the selected service are displayed, complemented with the text of the dynamic label.
Some data on the selected service - if any - can be found on a separate widget, the "Technical Data" widget (Detail button).
Most selectors are concentrated on the bottom part of the right side of the widget. Buttons to make scopes visible, to store input and or output into a file, to select input device and the audio and to scan and store a description of the ensemble are in that section.
Other widgets are
- a widget with controls for the attached device,
- a widget for additional configuration settings,
- a widget showing the technical information of the selected service as well as some information on the quality of the decoding,
- a widget showing the spectrum of the received radio signal, the constellation of the decoded signal and some quality parameters,,
- a widget showing the spectrum of the NULL period between successive DAB frames from which the TII is derived,
- a widget showing the correlations response(s) from different transmitters in the SFN,
- a widget showing the development - over time - of the SNR,
- if configured and data is detected, the time table for the current audio service
Another widget shows when running a scan; the widget shows the contents of the ensembles found in the selected channels. Since 3.5 the possibility exists to save a detailed description of the services in the different channels, in a format easy to process with LibreOffice or comparable programs.
Depending on a setting in configuration widget, a logo or slide, transmitted as Program Associated Data with the audio transmission, will be shown here or on a separate widget.
dabMini is a version of the DAB decoder with a minimal GUI. dabMini is built from the same sources as Qt-DAB, so modifications to the Qt-DAB sources are automatically applied to dabMini as well.
Other than Qt-DAB, there is no device selector. On program start up the software polls the availability of configured devices, the first one that seems OK is selected.
The GUI contains some selectors for setting device properties, depending on the selected device (usually gain, lna and agc). The picture shows the program using an SDRplay device, with agc selected and a selector for lna state. Since the agc is selected. there is no need for the if gain selector.
Current versions of dabMini supports the dlText and scheduler function as implemented for Qt-DAB.
duoreceiver is derived from dabMini and from other software for FM decoding. Since the SDR devices are covering both the FM broadcast band and BAND III, where DAB transmissions are, there were questions why dabMini could not be extended to cover FM transmissions as well. duoreceiver covers both bands and allows easy switching between FM and DAB.
An extensive "user's guide" - in pdf format - can be found in the "docs" section of the source tree. The documentation contains a complete description of the widgets, of the values in the ".ini" file, on configuring for creating an executable (Linux), and even a complete description on how to add a device to the configuration.
A preset option is available to allow storing and selecting favorit services. Touching the name of the currently selected audio service with the right hand mouse button will save the "channel:serviceName" pair in the preset list. Obviously, selecting a service in the preset list instructs the software to switch to the channel for the service and the service.
The presets are stored in an xml file, .qt-dab-presets.xml.
It is often the case that, for a particular device the optimal gain setting for channel X is not the same as for channel Y (assuming X != Y). This is especially annoying during scanning. Therefore, for each device, the gain settings for each channel are recorded and used whenever that channel is selected.
Setting colors is rather personal, that is why Qt-DAB provides the possibility of setting a color to buttons and displays. (in total there are 20 push buttons, 18 on the main GUI, 2 on the technical data widget).
To ease life a little, selecting a color setting for a button is now made easy: right clock with the mouse on the button, and a small menu appears on which the color for the button can be selected (one of a predefined list), and next a similar menu appears for selecting the color of the text on the button.
The settings are saved in the ".ini" file.
For setting the colors on the scopes, right click on the scope. Three questions will be asked: what will be the color of the display (background), what will be the color of the grid and what will be the color of the curve.
Many settings are maintained between program invocations in a so-called ".ini" file, ususally "qt-dab.ini", stored in the home directory. A complete description of the settings can be found in the user's manual (in the subdirectory docs). Touching the config button on the main widget will show (or hide) a widget where a number of settings can be adapted.
As known, Qt-DAB provides a possibility of scanning the band. Band III contains 39 channels, so - depending on your position - there is quite a number of channels where no DAB signal is to be found.
As in dabChannel, Qt-DAB has an extended mechanism to skip specified channels during a scan, a so-called skipTable. The configuration widget contains a button to make the skipTable visible. Such a skipTable shows all channels in the selected band, each channel labeled with a field containing a "+" or a "-" sign. Double clicking on the field will invert its setting. Obviously. skipTables will be maintained between program invocations.
When DX-ing, one wants to direct the antenna to different countries in different directions. Ideally there is a skipTable for each direction, and Qt-DAB supports that. The configuration widget contains a button skipFile, when touched a file selection menu appears where one can select a skipfile. If the file does not exist yet, it will be created. If one cancels the file selection, the default skipTable will be used, the same table that is used when no skipFile is selected.
Based on user requests an option is implemented to store the texts as emitted as dynamic label texts, into a file. The configuration widget contains - at the bottom - a button that - when touched - shows a file selection menu. The texts are preceded with a time indication and a service name.
12C.NPO Radio 5 2021-10-08 11:33:00 Rolling Stones - Jumpin' Jack Flash
12C.NPO Radio 5 2021-10-08 11:36:38 NPO Radio 5 - Arbeidsvitaminen - AVROTROS
12C.NPO Radio 5 2021-10-08 11:36:00 Kenny Rogers - The Gambler
12C.NPO Radio 5 2021-10-08 11:40:19 Fools Garden - Lemon Tree
Endless repetitions are avoided in the saved text. If saving dynamic label texts is selected as "command" in the scheduler, the texts will be stored in a textfile with a generated name.
The "alarm" facility is replaced by a more general scheduling facility. Touching the schedule button on the main widget shows a list of services to select from (the services in the currently selected channel, and the list of services in the preset list). A user specified time today or the next days can be linked to the selected service.
As additional feature, some operations can be scheduled as well:
- exit or nothing, with obvious semantics;
- audiodump, to schedule starting or stopping dumping the audio of the currently selected audio service;
- framedump, to schedule starting or stopping dumping the AAC segments of the currently selected service.
- dlText, to schedule starting or stopping recording the dynamic label text.
Note that selecting a different audio service will automatically stop dumping the audiodump and the framedump activity, the recording of the dynamic label text - if selected - is not affacted.
Specifying a time and day is stored in a table, maintained between program invocations. Of course, on program (re)start. On restart all schedule elements on passed dates are removed.
The current DAB standard eliminated the support for Modes other than Mode 1 and Bands other than VHF Band III, Qt-DAB still supports these features. Explicitly setting the Mode and/or the Band is possible by including appropriate command lines in the ".qt-dab.ini" file.
For the Mode, one will add/set a line
dabMode=Mode x, where x is either 1, 2 or 4
For the Band, one will add/set a line
dabBand=band, where band is either VHF Band III or L_Band
For windows an installer can be found in the releases section, https://github.com/JvanKatwijk/qt-dab/releases. The installer will install the executable as well as required libraries.
The installer will also call the official installer for the dll implementing the 2.3 api for getting access to the SDRplay devices.
For Linux-x64 systems, an appImage can be found in the releases section, http::github.com/JvanKatwijk/qt-dab/releases. The appImage contains next to the executable qt-dab program, the required libraries.
Of course it is possible to generate an executable, the aforementioned user's manual contains a complete script that can be used to install all required libraries, download the sources and build an executable on an Ubuntu (Debian) based system.
Since the main OS on the RPI's, has the same roots as Ubuntu, the script for Ubuntu can be used to install Qt-DAB on an RPI.
Note that the source tree contains two variants next to the Qt-DAB program, a dabMini program, a dab decoder with a minimal interface, and dab-2 an experimental variant. Both use large parts of the same sources as Qt-DAB does.
For dabMini, an appImage is available for use on an x64 based Linux system. The user's manual contains a complete script, tested on an RPI 2 and 3 for generating an executable.
dab-2 is experimental and NOT supported
Note that Linux allows connecting audio handlers as "pulse" and "pipewire" to bluetooth, making it easy to listen using a bluetooth connected soundbar or bluetooth connected ear- or headphomes.
There exist - obviously - other devices than the ones supported here. Interfacing another device is not very complicated, it might be done using the "Soapy" interface, or one might write a new interface class.
A complete description of how to interface a device to Qt-DAB is given in the user's manual.
While it is known that the DAB transmissions are now all in Band III, there are situations where it might is desirable to use other frequencies. If you want to experiment with a modulator, connected to an SDR device on other frequencies than the default one (or you want just to have a restricted number of channels from Band III or L Band), Qt-DAB offers a possibility to specify a list of channels to be used. Specify in a file a list of channels, e.g.
jan 227360
twee 220352
drie 1294000
vier 252650
and pass the file on 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.
Clemens Schmidt, author of the QiRX program and me defined a format for storing and exchanging "raw" data: xml-files. Such a file contains in the first bytes - up to 5000 - a description in xml - as source - of the data contents. This xml description describes in detail the coding of the elements. As an example, a description of data obtained by dumping AIRspy input.
<?xml version="1.0" encoding="utf-8"?>
<SDR>
<Recorder Name="Qt-DAB" Version="3.2-Beta"/>
<Device Name="AIRspy" Model="I"/>
<Time Value="Wed Dec 18 12:39:34 2019" Unit="UTC"/>
<!--The Sample information holds for the whole recording-->
<Sample>
<Samplerate Value="2500000" Unit="Hz"/>
<Channels Bits="12" Container="int16" Ordering="LSB">
<Channel Value="I"/>
<Channel Value="Q"/>
</Channels>
</Sample>
<!--Here follow one or more data blocks-->
<Datablocks>
<Datablock Number="1" Count="375783424" Unit="Channel">
<Frequency Value="227360" Unit="KHz"/>
<Modulation Value="DAB"/>
</Datablock>
</Datablocks>
</SDR>
The device handlers in Qt-DAB support the generation of such an xml file.
While the current implementation for reading such files is limited to a single data block, the reader contains a cont button that, when touched while playing the data, will cause continuous playing of the data in the data block.
The picture shows the reader when reading a file, generated from raw data emitted by the Hackrf device.
In Qt-DAB a first step is made to implement support for EPG (Electronic Program Guide).
In the current implementation, an EPG Handler is automatically started whenever within an ensemble a service is recognized as carrier of EPG data. The handler will collect information about the program guides for the various services, and when collected, allow the user to view it (it will take some time to have the relevant data collected).
Whenever the software has collected time table information of a given service, the technical Data widget will show, when selecting the service, a button labeled timeTable .
The software is experimental though and - at least here - the times on the time table in UTC.
Computation of the SNR is done with all DAB frames. As is known, a sampled DAB frame starts with a null period of app 2600 samples, followed by 76 blocks (each about 2500 samples) with data. SNR is computed as the ratio between the amplitudes in the data blocks and the amplitudes of the samples in the null period.
The configuration widget contains a spinbox that can be used to set the "speed" of displaying data. If the value "1" is chosen, the result of each snr computation is shown, if a value larger than "1" is chosen that number of computations will be averaged and the result shown. The default value for the X-axis of the display in the widget is 312.
As configuration option, the widget can be equipped with a dump button, touching the button will show a menu for file selection. Once a file is selected, the results of the computations are not only shown, but recorded in the file as well.
To view the recording, a simple utility is made to make the contents of the recording visible. Sources for the utility are to be found in the (sub)directory dumpviewer.
The picture shows the variations in the SNR when moving the antenna and - the dip - when switching antennas.
As (probably) known, the Adalm Pluto device has receive and transmit capabilities. In a previous project, an extension was made to a dab-cmdline version using the Adalm pluto device, to allow the transmission on FM of a preselected service.
As an exercise - and slightly experimental - the functionality was added to qt-dab.
If - on configuration - pluto-rxtx is included as device rather than pluto, and if pluto-rxtx is selected as (input)device on the main widget, the audio of the selected service, augmented with the text of the dynamic label encoded as RDS signal, will be transmitted on a specified frequency.
As default, the transmit frequency is 110 MHz, however, the user can specify the frequency (obviously within the range supported by the Adalm-Pluto) as command line parameter: starting the program from the command line with as parameter
-F XXX
will instruct the software to start the transmitter of the Adalm pluto - if the pluto-rxtx is the selected device - on the given frequency (specified in KHz)
Copyright (C) 2016 .. 2022
Jan van Katwijk (J.vanKatwijk@gmail.com)
Lazy Chair Computing
The Qt-DAB software is made available under the GPL-2.0.
The SDR-J software, of which the Qt-DAB software is a part,
is distributed 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.