new version of WPSKDEC software, allowing AO-40 and IDEFIX TLM decoding wdecpsk1.7e.zip 166 Ko

 

Index of the WDECPSK help:

-WDECPSK:

This software runs under Windows and uses the soundcard of your PC to demodulate and decode in real time the 400 bds PSK signal coming from AO-40.

-PREPARATION:

Use the predictions for the satellite to determine your antenna's direction.

Tune your receiver on 145.840 or 435.270FM (actually 435.278-cu8ao-)

Now you should hear the beacon of IDEFIX. (To let you familiarise with the sound of the telemetry beacon, a sample is included with the p3d.wav file.) If you don't, we will see in the next chapter how to do.

-CONNEXIONS:

Use an audio cable to connect the phone output of your radio to the "line in" of your soundcard. You should hear the sound of your radio in the pc speakers. If not, you have to select the "line in" in your soundcard or Windows menu. (click on start-programs-accessories-entertainment-volume control. Then select "options",then "properties". Select "recording", then check the "wave", "line in" and "volume control" boxes. Verify that the "mute" or "mute all" are not checked.) Now you should hear the sound of your radio on the pc's speaker.

-RUNNING THE PROGRAM:

You have unzipped WDECPSK in a folder on you hard disk. Open it, you should find 4 files: this doc, WDECPSK.exe, WDECPSK.log, WDECPSK.hlp and p3d.wav (I didn't find the last one -cu8ao-)

It is recommended to create a shortcut on your desktop, to turn things easier. Now, click on WDECPSK, and a window will open. If you have registered your software, enter your register information now. Click "OK". The main window of WDECPSK will open. Tune on the beacon of IDEFIX, and click on "FFT", a new window will open. You can see a moving red line, and a vertical green line on the upper side of the window.

The "Acquire" and "Sync_car" indicators are in black when the software is demodulating characters. The "Sync_block" is for a correctly decoded block. The message should appear in the lower window.

USING WDECPSK:

The software has 5 Modem state indicators:

• Automation: Another software is controlling the demodulator.
• Acquire: The software is getting data from the soundcard.
• Decode: The software is demodulating the signals.
  
• Sync_car: The synchronisation is acquired.
  
• Sync_block: The synchronisation of the message is acquired

A bargraph inform about the occupation rate of the circular buffer.
The circular buffer allows slow pcs to demodulate PSK directly from the soundcard.

The software has 3 command buttons:

• Start: Start an acquisition.
  
• Stop: The software stops the acquisition. The demodulation goes on until the circular buffer is empty.
  
• FFT: Shows a dialog box with the FFT of the input signal.

Manual mode:
The manual mode only uses the buttons explained before. To start an acquisition, you have to click on "Start"; the demodulation and data decoding will be done automatically. As soon a message is demodulated,it will show up in the text window.

To stop an acquisition, click on "stop" :-)

Translated from French by Fred, CU8AO, from the AMSAT-FR site.
If now you have found errors, please bear with me!
Corrections are welcome.
73, happy listening.
Fred.CU8AO