Re: LF: EbNaut test at 8270.00332 from JN64bw

[Markus Vester <markusvester@aol.com>]

After shifting the display range to the higher frequency, your signal is nicely visible on the DL0AO N/S spectrum (vlf20), around 12 dB in 21 uHz. There's also a small peak in 21 uHz at DF6NM in Nuernberg. Noise has gone down in the morning, and the storms in the Mediterranean seem to have calmed. Do you intend to leave leave the carrier on during the day?

Best 73,
Markus 

-----Ursprüngliche Mitteilung-----
Von: Riccardo Zoli <riccardozoli80@gmail.com>
An: LF Group <rsgb_lf_group@blacksheep.org>
Verschickt: Do, 21. Dez 2017 22:02
Betreff: Re: LF: EbNaut test at 8270.00332 from JN64bw

Hi Paul, Domenico, Markus, VLF

OK, Paul, thanks: very interesting RX statistics reports.

This night I'm in "troubleshooting mode" with a continuous carrier at:

f = 8270.01953125 Hz

Antenna current: 380mA

...looking for possibile unwanted phase rotation during TX.

All the best

73 de Riccardo IW4DXW

Il 21/Dic/2017 18:40, "Markus Vester" <markusvester@aol.com> ha scritto:

After fixing a problem with the DL0AO N-S antenna, we also attempted a decode. The resulting message doesn't look right though...

Will try again, hoping for quieter nights. Ric, I wonder if you could also transmit during the day?

Best 73,
Markus (DF6NM)


-----Ursprüngliche Mitteilung-----
Von: Alex K <rn3aus@gmail.com>
An: rsgb_lf_group <rsgb_lf_group@blacksheep.org>; Riccardo Zoli <riccardozoli80@gmail.com>
Verschickt: Do, 21. Dez 2017 18:27

Betreff: Re: LF: EbNaut test at 8270.00332 from JN64bw

Hello Riccardo, Paul, VLF!

Stacking procedure give me (I think false) decode "=D" with best rank 13...

My ebnaut-files of four 2-char transmissions  for reprocessing are here: http://rn3aus.narod.ru/IW4DXW-2char.zip

73 de rn3aus/Alex

found =D
list rank 13
reference phase -120 -150 -150  180
carrier S/N 10.56 dB in 24.8 uHz, -35.50 dB in 1Hz, -69.48 dB in 2.5kHz
carrier Es/N0 -17.72 dB
carrier Eb/N0 -0.01 dB
info bit period 3536.84 seconds
symbol error rate 285/672 = 42.411 %
Es/N0 from symbol errors -17.3 dB
Eb/N0 from symbol errors 0.4 dB
Shannon capacity 1.5 bits/hour
Shannon efficiency 70.1 %

-------------------------------------------------

2017-12-21 11:56 GMT+03:00 Paul Nicholson <vlf0403@abelian.org>:

Riccardo wrote:

> f = 8270.0033187866 Hz
> Start time: 20:00:00 UTC
> Symbol period: 60 s
> Characters: 2 (repea­ted)
> CRC bits: 10
> Coding 16K21A

After four repeats the results are now:

Todmorden 1413km
----------------

 17/18th Eb/N0 +4.0 dB, -31.5 dB in 1Hz, phase -117.5 deg *decoded*;
 18/19th Eb/N0 +6.0 dB, -29.5 dB in 1Hz, phase   +8.7 deg *decoded*;
 19/20th Eb/N0 +7.6 dB, -27.9 dB in 1Hz, phase  -35.7 deg *decoded*;
 20/21st Eb/N0 +4.6 dB, -30.9 dB in 1Hz, phase -164.7 deg *decoded*;

Bielefeld 845km
---------------

 17/18th Eb/N0 -3.1 dB, -38.6 dB in 1Hz, phase  -27.7 deg;
 18/19th Eb/N0 +0.2 dB, -35.3 dB in 1Hz, phase +111.2 deg *decoded*;
 19/20th Eb/N0 +1.4 dB, -34.1 dB in 1Hz, phase  +56.5 deg *decoded*;
 20/21st Eb/N0 +2.4 dB, -33.0 dB in 1Hz, phase  -80.9 deg *decoded*;

Cumiana 371km
-------------

 17/18th Eb/N0 +1.1 dB, -34.4 dB in 1Hz, phase +139.2 deg *decoded*;
 18/19th Eb/N0 +0.9 dB, -34.6 dB in 1Hz, phase  -96.4 deg *decoded*;
 19/20th Eb/N0 -8.3 dB, -43.8 dB in 1Hz (rx timing fault)
 20/21st Eb/N0 -5.4 dB, -40.9 dB in 1Hz (rx timing fault)

Warsaw 1035km
-------------

 17/18th Eb/N0  -5.8 dB, -41.3 dB in 1Hz, phase -28.3 deg;
 18/19th Eb/N0  -3.1 dB, -38.6 dB in 1Hz, phase +88.7 deg;
 19/20th Eb/N0  -1.8 dB, -37.3 dB in 1Hz, phase +97.1 deg;
 20/21st Eb/N0 -10.8 dB, -46.3 dB in 1Hz

Getting reliable decodes at Bielefeld.   Cumiana not timing the
signal very well, many thousand timing breaks each day
since something went wrong at 2017-12-19 06:42.

> A new transmission scheduled this night, trying a true
> "stacked decode" in Warsaw:

For unknown reason a poor S/N at Warsaw 20/21st.

Stacking 18/19th + 19/20th produces a false decode at +1.6 dB,
beating the correct decode at +0.5 dB.  Pure bad luck there.

Phase shifts from 18/19th to 19/20th:

 Todmorden:  -44.4
 Bielefeld:  -54.7
 Warsaw:      +8.4

Phase shifts from 19/20th to 20/21st:

 Todmorden: -129.0
 Bielefeld: -137.3

Still something is changing the phase from one night to the next.

--
Paul Nicholson
--