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 <[email protected]>
An: rsgb_lf_group <[email protected]>; Riccardo Zoli <[email protected]>
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 <[email protected]>:

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
--