That is good news, Domenico. Thank-you for finding my message in
the QRN QSB and QRM and for the files to practice decoding,
and also to Martkus and Stefan.
Yesterday a snow storm started and the SWR was very high as the snow
continued into the night. It's still snowing but we have been successful
so now can think about building a snowman after working on EbNaut RX!
73
Joe
On Sat, 3 Dec 2016, Domenico IZ7SLZ wrote:
Hello Joe & all,
With pleasure, i was able to decode VO1NA EbNaut message last night three
times:
UTC Eb/N0 [dB] Eb/N0 carrier [dB]
22.30 3.5 3.9
23.00 1.0 1.7
02.00 0.7 1.0
time and frequency offsets used are pratically the nominals values.
My locator is JN80nu so QRB is 5426 km: not bad for a message of 63
characters on LF sent in less than 30 minutes !
Antenna used here: inv-L 8 meters (my TX ant used untuned), receiver JRC
NRD-92M.
In the qsl.net folder:
http://qsl.net/iz7slz/VO1NA
i have uploaded the .wave files related to the above listed decodes. So
whom is interested, can try and test EbNaut-rx program. There are also
some txt files. These are the FFT raw data coming from the Spectrum Lab
OPDS session recordered last night. These files can be converted in
"EbNaut-ready" audio files by using DF6NM's program ebnaut_ifft3.exe. In
the folder, this program is included together with the configuration file
sr.txt in use on my setup.
So Joe, again thanks for your EbNaut activity, hoping to get soon an Rx
operator from the other side of the pond.
73, Domenico iz7slz
On 3 December 2016 at 00:57, <[email protected]> wrote:
Hi Markus, group.
Just confrimed that it is indeed 4K19A being transmitted.
Sorry for the careless proofreading of my emails!
Thank-you very much for the pilot tone suggestion. That
simplifies things greatly and with any luck there will be
an EbNaut RX here soon.
Cheers
Joe
On Fri, 2 Dec 2016, Markus Vester wrote:
Hi Joe,
a fax of Tangles' forehead
Yes those lines on the narrow spectrogram were indeed reminiscent of
cat's whiskers ;-)
use the stable DOXCO to divide out or synthesise an LO signal and mix it
in an SBL-3 as Stefan has done
But that would imply building a complete LF receiver from scratch,
including an image reject filter and some gain stages. A possibly quicker
alternative might be to use your existing receiver and only inject an weak
pilot tone from your DDS (eg. 137500 Hz) to the antenna, and then engage
SpecLab's frequency offset detector to eliminate any receiver drift. That
way soundcard samplerate drift won't be corrected, but that will have
little effect as long as the difference between the pilot and the desired
signal frequencies is less than a couple of 100 Hz. I have successfully
employed that method on MF to compensate the significant drift of my
freerunning FiFi-SDR, and was able to decode a number of EbNaut
transmissions (including yours) around 477.7 kHz.
Best 73,
Markus (DF6NM)
-----Ursprüngliche Mitteilung-----
Von: jcraig <[email protected]>
An: rsgb_lf_group <[email protected]>
Verschickt: Fr, 2 Dez 2016 7:15 pm
Betreff: Re: LF: EbNaut 137.477 kHz 1 Dec
Hi Markus and Stefan,
Thank-you for for your efforts in receiving and decoding the message. This
is encouraging -- it's good to know everyhing still works after the
hardware clean-up in the shack. I'll take care of forwarding the message
to Poldhu.
The slope and bends in the high res bpsk specrogram were intentional.
The element period T increased as a function of time and the bends are
actually curves due to the 1/T relation of the sideband deviation
from the carrier frequency I think.
It was a (poor) attempt to send a fax of Tangles' forehead (see
attached). She has been reminding me that she is interested in
getting a message from Gizmo and so I've been giving some thought
about reception. An idea is to use the stable DOXCO to divide out or
synthesise an LO signal and mix it in an SBL-3 as Stefan has done,
then to feed the product and a reference into the Spectrum Lab.
73 & TNX AGN
Joe VO1NA
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