GUI-Based, flexible screen layout, powered by the Windows Presentation Foundation (WPF).
Usable on large as well on small screens, by collapsable and expandable sub-windows.
Collapsed mode for using minimal space on the screen. DAB mux and service selection remain possible.
Number inputs on the main screen are done very fast by using the mouse wheel.
Aircraft and DAB TII Database Updates by a few mouse clicks from within the app.
Persistence on the hard-disk of all relevant parameters, accompanied by the saving of the complete GUI layout.
Multi-Frontend, TCP/IP- or file-input based, locally and remotely, allowing the simultaneous reception of up to three hardware devices of the same or different types, like RTL-SDR dongles, sdrplay or Airspy devices.
Raw-file replay (8- or 16-bit) of arbitrary sized files (many GBytes), with exact timing information, seekable. All GUI-based.
DAB, AM, FM, SSB and ADS-B Signals can be demodulated.
DAB Standard Features, like mux and service selectors, scanner with DX-features, Slideshow, Audio Recording of WAV or AAC files.
DAB Technical Information, like service quality, synchronization information, enabling experienced users to control their DAB reception.
DAB spectra, like Channel Impulse Response (CIR), Constellation and more, being displayed in collapsable windows.
TII Decoder. First SDR to decode the DAB Transmitter Ident Information (TII) of all transmitters contributing to a multiplex.
Map Integration, showing on a geographical map the Aircrafts detected by the ADS-B decoder or the DAB transmitters found by the TII detector.
GNSS Integration. Synchronized logging of the receivers geographical location together with the I/Q data when recording and/or replay raw data files.
Receiver Calibration. First app to integrate an ultra-fast method for the frequency calibration of cheap receivers usually showing many ppm's of frequency error, by using DAB.
Constellation visualization. First app to implement a linear (in contrast to circular) display of the DAB bit constellation, for a reliable Signal to Noise Ratio (SNR) calculation. Others have followed.
Airband Features not found in any other SDR, like the Channel Input or the Flip Switch for a quick exchange between the active and standby channels.
It would be great if you considered to use the QIRX SDR. In case the unprobable happens and you find an error, please send an email about it. Here you can find the history of the software. In case you think something might be wrong, please let me know! All comments are welcome!
QIRX like most SDRs processes so-called I/Q Data. In case you are not yet familiar with this important concept, you may find a nice introduction on the site I/Q Data for Dummies" .
The following hardware is supported by QIRX:
QIRX V3 is able to work flexibly in various configurationsv, purely local (i.e. the hardware connected to the local PC), purely remote (i.e. the hardware connected to one or more remote PCs), ore mixed local-remote.
For a more detailed description, please consult the Technical Report available in the download section.
The picture shows a nearly ideal spectrum of a DAB+ ensemble, 20-fold averaged (the degree of average is GUI-controllable).
Coarse timing and frequency checks are only performed after a complete synchronization loss.
Usually the constellation is displayed showing the bits as dot heaps in a polar diagram, like in the
following picture, from a report by Andreas Müller, ETH Zurich.
The dot heaps show the single bits, the heaps being separated by 90 Degrees.
QIRX uses a different, linear display for an improved visual control of the synchronization accuracy.
The picture shows an example: The spectrum (upper part) shows regions of strong multipath reception reducing the signal strength around 178 MHz. The constellation (lower part) shows – for each subcarrier – how well the bits are arranged on their correct position. Each dot corresponds to a single bit value. The reduced signal strengths around 178MHz clearly shows a much larger scattering of the bits off from their correct values. In a polar display it would not be possible to assign regions of large scattering to the frequency regions (subcarriers) with reduced signal strength.
This kind of constellation display can be used to obtain additional information.
In QIRX, the sampling rate error is permanently corrected. For more information and possible benefits of the sampling rate error correction you might wish to read the third part of our "Calibration" tutorial .