Re: VLF: EbNaut tonite, 'SMS' via VLF

[Markus Vester <markusvester@aol.com>]

Hi Paul,

> Do you have a version with higher sample rate?

Stitching together three shorter higher-bandwidth recordings from DL0AO, I managed to produce a seamless wav with 0.514 Hz samplerate:
 http://df6nm.bplaced.net/VLF/fec_tests/dl0ao_170524-25_join31uHz_wav.zip
Accounting for 7.8 s lag, this should require 2056.2 s start offset and 0.1 Hz frequency offset.  

Would you like to look again?

Best regards,
Markus

-----Ursprüngliche Mitteilung-----
Von: Markus Vester <markusvester@aol.com>
An: rsgb_lf_group <rsgb_lf_group@blacksheep.org>
Verschickt: Fr, 26. Mai 2017 3:52
Betreff: Re: VLF: EbNaut tonite, 'SMS' via VLF

Unfortunately not, the spectrum has been decimated to 0.1524 Hz bandwidth before the export. I could do sinc interpolation by zero-padding the spectrum but I guess that won't help much.

However I should have mentioned that SpecLab FFT recordings are usually delayed by a four sample latency. In this case it is ~26 seconds behind the file timestamp, which would surely prevent a successful decode if not accounted for in the start offset.

Best 73,
Markus 


-----Ursprüngliche Mitteilung-----
Von: Paul Nicholson <vlf0403@abelian.org>
An: rsgb_lf_group <rsgb_lf_group@blacksheep.org>
Verschickt: Fr, 26. Mai 2017 2:08
Betreff: Re: VLF: EbNaut tonite, 'SMS' via VLF

> The transmission was recorded at DL0AO using a synthetic
> cardioid antenna.

> here's our wav:
> http://df6nm.bplaced.net/VLF/fec_tests/dl0ao_05250424.wav (129 kB)

This doesn't seem to want to decode. Do you have a version with
higher sample rate?

--
Paul Nicholson
--