AW: Re: LF: 8270Hz-PHASE

[uwe-jannsen@kabelmail.de]

this is what leaves the antenna,
pse see the attachment
Uwe/dj8wx

 

Von: Paul Nicholson <vlf0403@abelian.org>
Gesendet: 14.03.2016 20:10
An: <rsgb_lf_group@blacksheep.org>
Betreff: Re: LF: 8270Hz

 

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
--
 

phase 15.03.16.png
Description: phase 15.03.16.png