Hello DK7FC,
Wednesday, December 14, 2016
Remarkable, quite remrkable and very well done Stefan!!
Best regards,
Chris 2E0ILY mailto:[email protected]
My part time LF grabber is at http://www.chriswilson.tv/grabber.html
>
> Hi ULF,
>
> My post-processing of the 4 day recording is still running, almost
> 50% of the data is shown on the spectrograms now.
> I'm happy to confirm the successful decode of a 5 character EbNaut
> message over 65 km on the 101 km band, with a BIG SNR! It's the one
> which started on 08.DEC, 7 UTC. First there was no decode until i
> found that i made a mistake, the actual start of the transmission is
> 6:58:40 UTC, an offset of -1 symbol.
> Capture in attachment. I also attach the wav file, if someone
> wants to play with it, the size is very small.
>
> 73, Stefan
>
>
> Am 12.12.2016 14:50, schrieb DK7FC:
>
> Hi ULF,
> More news from the latest experiment on the 101 km band with QRB ~ 65 km.
> Yesterday i have been in JN39VH41HLagain and took all the equipment
> of this ULF experiment home again.
> Everything has still been there and in its right place, which was
> the first good message. Here's an image showing the coupling of the
> loop antenna, 2 turns primary and about 200 turns secondary on a big
> ferrite core:
> https://dl.dropboxusercontent.com/u/19882028/ULF/20161211_123535.jpg
> Even the audio recording process was still running but the USB
> stick was almost full. Now i have saved a 29.7 GB raw file
> containing the audio data for post processing. This recording is
> almost 4 days long. 2 SpecLab instances are now running to produce
> spectrograms in 424 uHz FFT bin width and 10 minute per pixel scroll
> rate, using a noise blanker and a 4 kHz wide filter centered on 2970 Hz.
> The accus (5x 7 Ah lead gel) were discharged to 12.17V,
> https://dl.dropboxusercontent.com/u/19882028/ULF/20161211_123758.jpg,
> so it was the right choice to use these 5 accus.
> The single turn vertical loop circumference is about 45m out of
> 1.5mm^2 cu wire and the captured area is about 70 m^2.
> Now, while writing this mail, the first pixels are coming in. So
> far the result is looking very very good, the SNR seems to be
> arround 20 dB, much more than expected! See attachment. I will write
> a summary when all the spectrograms and eventual EbNaut decodes are
> available. But in the moment it looks most promising that i
> successfully crossed 65 km distance on the 101 km band, which was
> the goal. This is the
> path:http://no.nonsense.ee/qth/map.html?qth=JN39VH41HL&from=jn49ik00wd
> 73, Stefan/DK7FC
> Am 09.12.2016 15:43, schrieb DK7FC:
> After doing a lot of modifications here on the TX side, the effect
> still exists. I can't get rid of the unstable phase shown on the VLF tree
> grabber.
> One thing to mention is that the phase seems to change slowly, no
> sudden phase jumps. Thus the peak is 40 dB S/N in 47 uHz. So
> obviously there were much less uncorrected phase glitches than
> expected in the first moment when i saw the effect.
> Just to be sure i downgraded to the last SpecLab version, the one i
> used since the last month. But the effect still exists.
> Next to note is the i never saw the effect in my last tests. I
> still have captures showing a very clear trace on 2970 Hz during the
> 31 km experiment. OK that was in September. The QRN levels may have
> been a bit higher and the signal was 7 dB weaker. So maybe the
> effect was just hidden in the noise?
> Next i found that some SpecLab configurations seem to be corrupted
> by forth and back installing old (V2.90b2) and new (V2.92b2)
> version. So i am now using the old version and a config file that
> was never opened in the new version. It all seems to work fine on
> the TX side but i can still see the effect. BTW i even disabled the
> NB and checked if this makes a change. But thill the same result.
> The TX schedule for the experimentis:
> 07.DEC: TX 2970.000 Hz (antenna current between 105...110 mA all
> the time) since 13:30 UTC. The recording has started about 15 UTC.
> 08.DEC: EbNaut 5ch, 80s, 8K19A @ 2970.000 Hz starting 7 UTC, ending
> 18:22:40 UTC. Then, carrier at 2970.000 Hz. Some interruptions happened in
> the late carrier.
> 09.DEC: 0 UTC starting DFCW-10800 (3h per element), 'dit' at
> 2969.9975 Hz, 'dah' at 2970.000 Hz. The message is 'FC'. Between F
> and C there is a break of 7 hours. In this time, starting 15 UTC:
> EbNaut 2ch, 68s, 8K19A @2970.000 Hz.
> 10.DEC: End of DFCW message 'FC' at 13 UTC. Then, EbNaut 5ch, 80s,
> 8K19A @ 2970.000 Hz starting 13 UTC (repetition of the message of 08.DEC.)
> 11.DEC: End of EbNaut message at 0:22:40 UTC. Then, carrier on
> 2970.000 Hz until 20 UTC. The recording will stopp in the late
> morning, due to space limitations of the 32 GB USB-stick.
> From the local recording i tried to decode the 5ch EbNaut message.
> But it didn't decode. I just got a '*****' message and a false
> decode. This is strange. The dots are quite concentrated in the two
> horizontal lines which indicates a stable phase. See attachment.
> Also the signal peak is strong and narrow. But in the red field
> there is nothing to see... This EbNaut message was transmitted with
> the new PSK config in SL. It is the reason why i will repeat the
> message in the end of the experiment again, using the old settings and
> version.
> I should have done more pre-tests before starting the experiment.
> But now it is running. Well, the main goal is to detect a clear
> trace of my signal in a spectrogram running at 300 uHz or so. The
> signals do not look bad on the local grabber, not at all, despite
> the strange (propagation?) effect. I'm still optimistic...
> 73, Stefan
>
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