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Hi
Bob,
thanks for the feedback. At this stage, the
cancellation procedure is no more than a proof-of-principle, done in
postprocesseng on recorded audio. The purpose was more to check if
my theory about the cause of the interference is valid. I can generate
a visual spectrogram, but it won't be easy to extend that
to a quasi-realtime software plugin which could feed WSPR, Opera or
opds. Guess it might be suited for implementation as an FFT
filter plugin for SpecLab, but I'd need a crash course in DLL programming before
I'd be able to do such a thing ;-)
I'm also not sure how much DCF77 is currently
affecting others. Spectrograms from Henny and Hartmut have occasionally
contained some similar interference but at much lower level. On the other hand,
if someone located closer to Frankfurt (eg. Stefan or Marco) would attempt
to receive on 74 kHz, they would certainly suffer more than I
do.
Well once the wind calms (may be Saturday
night) I can put my antenna back up and listen again. I'd be very
interested to look for visual signals from you and Dex one of
these nights. Preferably even slower than QRSS-60, say QRSS-120 or DFCW-180.
On the other hand, I can set up either
opds-32 or -64 (whichever speed you prefer), or WSPR on 74.55
kHz. However these would not benefit from the DCF noise
cancellation.
Best 73,
Markus (DF6NM)
PS On 137kHz, last night WE2XEB produced a
couple of opds detections here, despite the low and noisy "summer" receive
antenna. Thanks for the effort to produce such a good
signal!
Sent: Friday, December 06, 2013 4:00
AM
Subject: RE: LF: Cleaning up DCF77
junk around 74.55 kHz
Markus;
That could most certainly
improve things for 73 band use. Especially for those close, as you
are to the offending emissions.
I am ready to go back to 74 tomorrow
anyway. Will continue with QRSS 60 and 74.5495.
Let me know when
you might be ready I can also summon Dex for his signal
one hertz away.
The interference was not the reason for requesting
other modes but was to introduce something in the way of a new emission for the
band. QRSS has proven it's worth and just wanted to try something
else. To do so with a clearer freq would only help
matters-Bob
I think I have found a way
to eliminate interference from the DCF77 pseudonoise modulation
in 74.55 kHz spectrograms.
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