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)
