Category Archives: FM

SDR-J DAB (Digital Audio Broadcast) and SDR-J 5.0

DAB SDR receiver and new version of the swreceiver available

Following the introduction of the DAB sdr, recently, we now present a new version of the software with some improvements. Many users of the previous version(s) gave their feedback and helped to improve the software.

The DAB decoding software is extended with other DAB Modes (now supporting Modes I, II and IV), the GUI has a selector for the Mode and is extended with a selector for choosing between band III and the L-band.


The FM software is merely unchanged: some minor errors were removed. The FM receiver takes advantage of the bandwidth provided by the DAB stick output and shows a larger spectrum (the width can be set) from which the FM signal is taken. My favorite setting is 240000 samples/second for the FM decoding and a display of 2400000 Hz. Setting is through the “.ini” file, the manual contains the details.


The spectrumviewer has as gadget the possibility of showing a sequence of subsequent parts of the spectrum. The number of parts from which the total image will be built can be set through the ini file.


As usual, the software is in a Windows and a Linux flavour. The Windows distribution is as a “zip” file,

containing the three executables and the required dll(s). Note that for execution, the msvcr100.dll is also required!!

We still only provide 64 bit versions of this software. It is obviously possible to generate a 32 bits Windows version, but for the time being functioning of the DAB decoding software on Windows 32 bits is not what it should be. I am sorry for that, but it is just what it is!!! (All kinds of suggestions are welcome, the 32 bits windows executable runs perfectly under Wine on my laptop).

In general, one needs a pretty heavy machine for running the software: it runs flawlessly on my laptop with a 2.5 GHz i5 processor both under Fedora and Windows 7. It – more or less, depending on the OS – runs on an older machine with a 2.0 G duo Core.

The Linux distribution contains the packed sources


A manual for the DAB programs is available.


This manual also contains a list of the required libraries for building an executable as well as instructions for building these executables for Linux.
NEW is the addition of CMakeList.txt files to support building using the CMake system (It remains required though to make the various libraries and the corresponding “include” files available and to adapt the CMakeList.txt files to the local environment).

Version 5.0 of the swreceiver (32 bits) is now also available.


The swreceiver suite consists of three programs, the actual swreceiver, the swbackend and the fmreceiver. These programs are crosscompiled for a 32-bits windows environment, again, for Linux the sources are available.

The swreceiver is an improved version of the previous swreceiver. It supports the Elektor card, the pmSDR and DABsticks directly, and – in a limited form – dll’s conforming to the Winrad standard, those delivering data through the soundcard. For both DABsticks and the pmSDR an offset can be specified for use with up- or down converters. For DABsticks this offset can be specified with an accuracy of 1 Hz. Both input-handlers and decoders are now implemented as plugins.
Furthermore, next to a regular dump facility, there is the possibility of writing the samplestream that is sent to the decoder to a “wav” file. Such a file can be (re)used with the swbackend, using the same set of decoders.
There are decoders for the analog modes (am, ssb, sfm). Obviously there are decoders for cw, rtty and (q)psk, mfsk and a few others.


The swbackend is essentially a strongly reduced version of the swreceiver: it merely provides an interface to the different decoders. The swradio and the swbackend share the same set of decoders. The swbackend will read from the soundcard (e.g. output from “classic” receivers) or from “wav” files, e.g. produced by the swreceiver. It is capable of translating “mono” signals from the product detector of “classic” receivers to analytic signals, for use in the decoders.


The fmradio is what its name suggests: software with an FM decoder. It shares the set of input devices with the swradio, through the use of plugins. It shows pretty good FM with the pmSDR and with dabsticks. Bandwidth is, however, limited to 192K. For devices that are not capable of receiving the FM broadcast band, the program provides the possibility of decoding AM with a variable bandwidth.


For configuration purposes (the “ini” files have to be told where to find the plugins), there is a small configuration utility


The Windows software is distributed as a “.zip” file. Unpacking will create a folder “sw-distr-5.0” with in it a folder “bin” and a folder containing the manual. The “bin” folder contains the executables, the dll’s and the two (sub)folders with the plugins.

The Linux software is – as usual – distributed as a “.tgz” file.


The manual contains a pretty extensive description of how to build the software and a fairly detailed description of how to use the software.


Reports on user experiences and suggestions are welcome.
Have Fun!!!

Pijnacker, September 2013
Jan van Katwijk