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:
Op-8 1.024s 0.9766
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