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