Re: LF: EbNaut 137.477 kHz 1 Dec

[jcraig@mun.ca]

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 <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. 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