Hi SpecLab co-users,
Wolf's powerful program has a built-in terminal for digital modes for a SSB
TRX. One of them is a Parallel-Multitone Hell modulator, which generates
tones from the typefaces of text entered into the terminal. Combined with a
font editor (e.g. Softy by D.W.Emmett), this becomes a universal tool to play
with visual modulation schemes. The resulting tones are individually
phase-coherent and can be soft-shaped to avoid clicks.
For narrowband DFCW, I have prepared a font consisting of two lines of dashes
and gaps. To use it, you have to copy the .fon file to the Windows\Fonts
directory. After starting SpecLab and the digimode terminal, you can choose
"DFCW" and enter Size = 1 in the Settings / Select HELL font menu. In
Digimode Configuration, you select Parallel MT mode and then set Symbol Rate,
TX Center Freq and FSK shift. For example, a symbol rate of 0.05 baud gives
3*20s dashes and 20s intervals. The dash and dot frequencies are related to
the settings as
f_H = CF+ FS * 4/8 and
f_L = CF+ FS * 3/8,
e.g. CF = 1422 Hz and FS = 0.8 Hz produces 1422.4 / 1422.3 Hz tones. An
output level of 800% will give full scale DAC output, and the Symbol shaping
time can be set for smooth edges (e.g. 20%).
After you have pressed TX, any text entered will be sent to the audio output.
Please don't look for all the special Morse characters, "sk" can be sent by
typing # . Normally, the audio input and waterfall is automatically disabled
during transmission, but you can reactivate it for duplex mode by clicking on
the Sound-In box in the SpecLab Components diagram. To see your own signal as
well, you may have to set up an analog loop by enabling Wave input in
Windows' recording mixer.
The other fonts are for CW/QRSS and the new 7FSK mode. For CW, simply set FS
to 0 and CF to the desired audio note. The 7FSK freqs are
f7 = CF + FSK * 4/8
...
f3 = CF
f2 = CF - FSK * 1/8
f1 = CF - FSK * 2/8,
e.g. CF = 2289.85 and CF = 1.2 above 135500 Hz zero beat gives Andy's set of
frequencies.
I have decided to add an extra space after each 7FSK pair. This does slow
down the mode by a third, but it allows easier synchronization for the RX as
well as QSK to watch between characters on the TX site, and it gives the PA a
rest.
Tnx agn to DL4YHF for SpecLab.
Happy experimenting
de Markus, DF6NM
CW_FONTS.ZIP
Description: Zip archive
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