Re: LF: 8270Hz

[Paul Nicholson <vlf0403@abelian.org>]

Uwe wrote:

> can I get somehow your 8270Hz .WAV file from today

I made three WAV files suitable for input to ebnaut-rx
(the header contains frequency and time info).  All
files begin 02:59:00 and decode with a start offset
of 60.00

Various sample rates and file sizes:

 30 samples/sec 2.8 Mbyte Eb/N0 = 1.0 dB
 http://abelian.org/vlf/tmp/dj8wx_160314_30.wav

 10 samples/sec 936 Kbyte Eb/N0 = 0.6 dB
 http://abelian.org/vlf/tmp/dj8wx_160314_10.wav

 1 samples/sec 96 Kbyte Eb/N0 = 0.4dB
 http://abelian.org/vlf/tmp/dj8wx_160314_1.wav

I notice that the error rate increases a little as I reduce the
bandwidth. Here I usually decode from a rate 240 samples/sec
and got Eb/N0 = 1.2 dB but it's down to 0.4 dB after resampling
to the lowest rate.   I'm not sure why that is.

> the carrier is on.

Amplitude and phase plotted in 5 minute steps

 http://abelian.org/vlf/tmp/160314b.gif

Some pretty wild variations of phase but it
settles down from about 02:00 onwards.   I tried
to decode the earlier carrier as an 'all-star' message,
but without success at symbol length 10 seconds.

--
Paul Nicholson
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