WSPR Decoder User Manual

  1. Introduction
  2. Operation
  3. Bugs and annoyances
  4. Copying

1. Introduction
The WSPR code decoder is a Receive-only Guest mode for the lhpsdr HPSDR client. The source code used here has been adapted and imported into lhpsdr from the rtlsdr-wsprd application by Guenael, VA2GKA and WSJT-X application by Joe, K1JT. I had to make a number of changes to the code to remove the FFTW dependency (replaced by the built-in FFT function of lhpsdr) and to modify the CIC decimator and its FIR filter. Results from the Detector are presented in a GTK text viewer and displayed in an Xplanet map with great circle paths drawn.

2. Operation
The WSPR Guest mode is selected from the Guest Modes->WSPR menu item. This opens the WSPR mode's window and sets up lhpsdr in the appropriate Receive mode for WSPR signal detection. Decoder functions are controlled from the widgets in the bottom row of the window. The Decoder can be started by the "Start Decoder" toggle button and the band/frequency can be selected from the "Fr. MHZ" combobox, at the bottom left of the window. In the middle of the row is a short status display the indicates the current activity of the Decoder. Next are two check buttons: "Post" enables reporting of WSPR spots to whispernet.org using curl and the internet connection. Xplanet enables the display of spots in an Xplanet window with Great Circle arcs from the Home location to the Remote WSPR location. The "Clear" button clears the GTK text view that displays information on detected spots and the "Quit" button closes the WSPR window and stops the Detector.

The WSPR Decoder displays the following data:
The Spot number, starting from 1.
The Date and Time of the Spot.
The dT Timing discrepancy of the WSPR transmission.
The Frequency of the WSPR station and the dF deviation.
The WSPR "message", e.g. the call sign of the WSPR station, its QRA locator and the Tx power in dBm.
Finally the Bearing and Great Circle short path distance to the WSPR station.

3. Bugs and annoyances

The WSPR Decoder has been working very well and seems stable. Please report if any bugs are noticed.

4. Copying This software package is released under the GNU Public License. Please see the COPYING file for more details.

This program 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: