Date: Sat, 3 Dec 2016 11:27:08 -0330 (NST)
From: jcraig@mun.ca
To: "rsgb_lf_group@blacksheep.org" <rsgb_lf_group@blacksheep.org>
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Subject: Re: LF: EbNaut 137.477 kHz 1 Dec
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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 fil=
e
> 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, <jcraig@mun.ca> 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 i=
t
>>>> 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 quick=
er
>>> alternative might be to use your existing receiver and only inject an w=
eak
>>> pilot tone from your DDS (eg. 137500 Hz) to the antenna, and then engag=
e
>>> SpecLab's frequency offset detector to eliminate any receiver drift. Th=
at
>>> way soundcard samplerate drift won't be corrected, but that will have
>>> little effect as long as the difference between the pilot and the desir=
ed
>>> 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)
>>>
>>>
>>> -----Urspr=C3=BCngliche Mitteilung-----
>>> Von: jcraig <jcraig@mun.ca>
>>> An: rsgb_lf_group <rsgb_lf_group@blacksheep.org>
>>> 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. T=
his
>>> 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 messag=
e
>>> 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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