Today I finally found a simple solution to send Opera sequences from SpecLab's digimode terminal. The nice thing about this is that you can use all of SpecLab's powerful functions, like samplerate correction, adjustable pulse shaping, or high audio frequencies. This seems very useful, especially in the context of possible future VLF Opera transmissions.

 

First you will need to create a text file consisting of the 239 bit 1101... sequence for your callsign. This can be generated from the PIC menu in the original Opera software. Or you can use my little code generator tool at http://df6nm.bplaced.net/opera/opera_generator.zip - simply copy opgen.exe from the zip and type

 opgen mycallsign >opera.txt

into a command window.

 

In SpecLab, open the digimode terminal and configure it for ASK with no encoding, as shown in the attached "_settings" screenshot. The symbol rate has to be set to the inverse dotlength for the desired Opera speed:

 

mode   dotlength    rate

          (seconds) (sym/s)

Op-8    1.024s     0.9766

Op-32   8.192s    0.12207

Op-4H  65.536s   0.01526

 

Shaping time can be selected from hard (0%) to soft (50%) keying. Then enter your desired audio frequency and use "Load TX text" from the file menue to load your opera.txt file. The sequence will appear in the TX window, and the transmission can started by hitting the RX / TX button.

 

Best 73,

Markus (DF6NM)