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Opera deep search users,
here are some details on how
to adapt opds to the new Op-2H mode for 29.5 kHz.
If you are using an USB receiver, you
could tune to 27.98 kHz dial and process the audio band around 1.52
kHz. This will put Bob's QRG near the middle of the passband of
standard Opera software, so if you want you can run both side by side.
The
following settings will then let opds analyze a 3.9 Hz wide passband
centered on 29.500 kHz:
Audio samplerate:
12000 Hz
FFT decimate (divisor):
1536
FFT length: 65536 (119.2 µHz bin width).
FFT center frequency: 1520 Hz
Number of exported FFT bins: 32768
Waterfall scroll interval: 30 minutes
L2 bandpass filter before noise blanker: center
1520 Hz
In opds.ini, the following lines need to be
edited:
opspeed=128 'Op-2H speed
(approx. minutes)
spotdelay=116 'delay spot timestamp the same
way as Opera (seconds)
fc=29500 'FFT
center frequency
(Hz)
sr=12000 'your
calibrated samplerate (Hz)
dec=100663296 '1536*64K decimation * FFT
length
Many built-in soundcards are now supporting 96 kHz
ADC samplerate. If you own one of these, the much prefered option would be to
connect the antenna directly to the soundcard, doing away with the receiver and
it's possible drift. In SpecLab, you
would then directly enter 29500 Hz center frequency for the bandpass
and the FFT, select an approximately 8x higher FFT decimator from
the dropdown list (13824 instead of 1536), and modify the dec factor
in opds.ini accordingly (dec=905969664). You
can then use samplerate correction with one of the military MSK stations to
remove any remaining drift.
Finally you will have to enter potential
transmitting stations to the search list callsloc.txt:
WH1XBA fn12lq
WH2XBA fn42hi
WH3XBA
fn31ls
WH4XBA em95tg
WH5XBA bp51gn
WH6XBA em47em
Disclaimer: These are untested "theoretical"
settings, please post if you find errors or corrections.
Good luck!
73, Markus (DF6NM)
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