Новости LF/VLF/ULF/SLF/ELF > VLF (ОНЧ — очень низкие частоты) диапазон с частотами от 3 до 30 кГц
17.47 kHz DK7FC - VK7/Edgar Ebnaut one-way
rw3adb:
A successful transmission, on 17470.1 Hz, of a two character EbNaut message was completed on the 10 th September 2018.
The transmitter was at JN49ik, Germany and receiver at QE37pd Tasmania a path of ~ 16786 km (10491 miles).
The message was decoded by processing the signals received on the 8 th and 10 th of September 2018.
The software used was
Spectrum Lab by Wolfgang "Wolf" Buescher ( https://www.qsl.net/dl4yhf/spectra1.html ) and
EbNaut Coherent BPSK programs, by Paul Nicholson ( http://www.abelian.org/ebnaut/ )
The receiving set-up was a 1 m whip with a FET buffer at 9 m, a Steinberg UR 242 audio interface,
a Garmin GPS unit and Asus notebook.
Thank you to Stefan Schaefer DK7FC for his help and guidance to make this possible, and Wolf and Paul for their excellent software.
Regards, Edgar
Moonah, Tasmania.
P.S. Message re-sent with smaller image
rw3adb:
> Not sure if everybody can really understand how weak and
> buried in noise was that signal ...
1.6 info bits per hour across a 16800 km path, 42% of the
Earth's circumference, using 2mW, much less than the power
of a small LED.
S/N -65 dB in an audio bandwidth.
Not a bad result there, at a range of 183727 American football
stadiums.
Added to http://abelian.org/vlf/amateur-radio/
--
Paul Nicholson
--
rw3adb:
Edgar, VLF,
My congratulations and respect for your permanent available well working RX system and your patience. When looking back, i remember a number of remarkable achievements we made, also on LF. Great work!
As you say, credits go of course to Wolfgang, Paul and Markus for their great tools and help. Very much has been developed in this decade.
What now? Are 3 characters realistic? We learned that normalizing and stacking can be quite a complex thing and there is that propagation over this path which is not completely predictable and not always reproducable.
I'm going to try 3 characters which needs about 12 dB SNR. But first, some carrier transmissions again...
Roman, i used the inverted L antenna, not the loop. Antenna current was 1.2 A. That's about 320 W and about 23 kV on the antenna, i.e. quite relaxed ;-)
73, Stefan
rw3adb:
Отчего-то сперва подумал, что Стефан использовал земляную антенну из дорожного отбойника в этом эксперименте, потому писал в ту тему. потом решил все же уточнить у него, он ответил только сегодня - потому создал отдельную тему посвященную этому эпохальному событию.
Р6ЛДД:
--- Цитата: rw3adb от 15 Сентябрь 2018, 00:58:17 ---42% of the
Earth's circumference, using 2mW, much less than the power
of a small LED.
--- Конец цитаты ---
Впечатляет. Без сравнения звучало бы суховато.:)
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