FM – DAB+: my logblog!

QIRX 2.1.1.8 maintenance release.
QIRX sometimes crashed on high map tile download requests.

Download here. Read up on the history here.

Today QIRX 2.1.1.7 was released by Clem Schmidt.
Download here.

What’s new? Copied from the QIRX-History page.(© Clem Schmidt)

• Installer
  Starting with this release, QIRX will be downloadable as a standard Windows Installer file (.msi). The installation is started by double-clicking this file. Per default the code with all necessary files and drivers is installed into the “Program Files” directory.The data files are installed in the standard user application data directory, mostly looking like so:
  C:\Users\<your user name>\AppData\Local\qirx\
  The qirx.config file must reside in that directory. All of the other directories might be edited in the qirx.config file if appropriate, by hand.For special applications, the introduction of the installer still allows the use of more than instance of qirx. However, to run error-free, the second instance should reside in another directory, like e.g. in a version lower than this one. Please note that in this case also the directories for the data have to be adjusted manually in the qirx.config for that other instance.
• TII Tab
  TII Averaging: Its time can be adjusted with the “Average” slider. In this way it is possible to adjust the averaging according to the application profile:
  • High sensitivity: Large averaging time.
  • Good realtime response times: Small averaging time.

  Thanks to Petr, OK2HF, who motivated the introduction of this feature, as he noticed the TII values lagging behind due to the large averaging of several minutes.

  TII Collisions: Different Main Ids using the same Sub Id cannot be resolved by the TII decoder. These “collisions” can now be shown by checking the corrsponding checkbox. There will be a tutorial explaining how to make use of this feature, and – with some luck – resolve the collisions.

  TII List Entries: Each contains a checkbox. If selected, ith shows in the TII spectrum the carriers generating the TII.

• Scanner
  The scanner in its current version sometimes needs more time to stabilize on an ensemble than provided by the default value, in particular when the receiver is not properly calibrated. It is possible to adjust this time in the scanner dialog. It is called “Delay Time Before Ident”. This is another feature having been suggested by Guido Schotmans.
• Map
  Right-clicking into an ensemble icon now offers the “Info” context menu. On activating it, it shows – for that transmitter – the whole information contained in the database.
  Another context menu item selectable by clicking in an empty region of the map allows to remove all presently visible inactive, i.e. grayed icons on the map.
• Raw Files
  The files of a raw recording are prepended with a xml header, containing the relevant metadata. This feature, suggested by qirx, has been a common effort between the authors of Qt-DAB and QIRX. This header will be described in some more detail elsewhere.
  With this header, it is no longer necessary to change configuration settings for a specific replay. However, for backward compatiblity, raw files without header remain possible.
  In QIRX, – implemented since 2.1.1.5 – it allows e.g. for the following new possibilities:
  • Changing the ensemble during a recording, and having that change reflected in the same way on replay.
  • Display of Frequency and Block Id during a replay.
  • Display of application and device used during the recording.
• Sampling Rates
  For experimental purposes, different sampling rates can be selected in the configuration. This allows for instance to run the Airspy with its native sampling rate of 3Msps. A corresponding fractional resampler, based on Lagrange Interpolation (with an order of two, using parabolas as polynomials) has been realized, together with the necessary filtering.
  This feature is of course also usable for the replay of corresponding raw files.
• Hardware Gain Level indication
  For RTL-SDR compatible dongles, an enhanced rtl_tcp.exe reports the value of the overall gain used by the Tuner . It is indicated in QIRX in the “R820T” tab as a percentage level number. 100% mean the tuner is using all of its possible gain.
  In the rtl_tcp.exe, this feature again has been developed by rundfunkforum user Oldenburger, adding another enhancement of this popular hardware to his long successful AGC and HW Filter developments.

Jan Van Katwijk today released Qt-DAB 3.2-Beta. Download it here.

What’s new?
‘Two visual changes are the display of time, and the quality indicator.
The latter is based on a different algorithm and the value range is roughly from -3 to 3,
where 3 is excellent.‘