Re: LF: 8269.9 kHz EbNaut 31/12/17

[Markus Vester <markusvester@aol.com>]

Thanks to Dex for the signal and to Paul for the phase data. Unfortunately no joy here yet. I applied the suggested phase corrections (both positive and negative) with inverse noise power weighting in a small Windows batch script

add 8k27w_12280249.txt -6 0
add 8k27w_12290249.txt -10 118
add 8k27w_12300249.txt -8 236
add 8k27w_12310249.txt -4 260
add 8k27w_01010249.txt -14 257
ren sum.txt sum2.txt

but got only a few presumably false decodes with high rank numbers (08Y, ET+, 2ZA, and N8E).

Last night was rather noisy due to storms over the French Atlantic coast. I would like to try two more nights (i.e. one week in total). If nothing comes out after that, I will ask the dormouse to tell me the message and look for correlations.

Regarding the transmitter phase steps: As opposed to SpecLab's 1pps lock, the phase of a signal generator or DDS synthesizer will only be maintained if it is running continuously without any interruptions. I'm wondering if the discontinuities might be caused by temporary GPS outages during the day (jamming from North Korea? ;-), or perhaps intentional manipulations of generator frequency e.g. while checking antenna tuning.

Best 73,
Markus 



-----Ursprüngliche Mitteilung-----
Von: Paul Nicholson <vlf0403@abelian.org>
An: rsgb_lf_group <rsgb_lf_group@blacksheep.org>
Verschickt: Mo, 1. Jan 2018 18:01
Betreff: Re: LF: 8269.9 kHz EbNaut 31/12/17

Dex wrote:

> Repeat number 5

> 8269.9 kHz
> repeat message
> 3 chars 16K21A CRC20
> 30 second symbols
> Start 22:30 UT

Todmorden (6194.2 km)
---------------------

27/28 Eb/N0 +9.2 dB, S/N -22.9 dB/1Hz, phase -140.9 *Decoded*
28/29 Eb/N0 +5.4 dB, S/N -26.7 dB/1Hz, phase 108.7 *Decoded*
29/30 Eb/N0 +10.2 dB, S/N -21.9 dB/1Hz, phase -12.8 *Decoded*
30/31 Eb/N0 +7.9 dB, S/N -24.2 dB/1Hz, phase -32.4 *Decoded*
31/01 Eb/N0 +2.9 dB, S/N -29.3 dB/1Hz, phase 115.6 *Decoded*

Bielefeld (6917.7 km)
---------------------

27/28 Eb/N0 -2.6 dB, S/N -34.7 dB/1Hz, phase 71.2;
28/29 Eb/N0 -2.3 dB, S/N -34.4 dB/1Hz, phase -45.2;
29/30 Eb/N0 -3.3 dB, S/N -35.5 dB/1Hz, phase -161.9;
30/31 Eb/N0 +0.8 dB, S/N -31.3 dB/1Hz, phase 160.1 *Decoded*
31/01 Eb/N0 -4.8 dB, S/N -36.9 dB/1Hz, phase -41.2;

Warsaw (7681.3 km)
------------------

27/28 Eb/N0 -7.4 dB, S/N -39.6 dB/1Hz, phase 143.3;
28/29 Eb/N0 -11.5 dB, S/N -43.7 dB/1Hz, phase 85.6;
29/30 Eb/N0 -6.8 dB, S/N -40.0 dB/1Hz, phase -46.2;
30/31 Eb/N0 -16.5 dB, S/N -48.6 dB/1Hz;
31/01 Eb/N0 -17.2 dB, S/N -49.3 dB/1Hz;

Cumiana (7173.4 km)
-------------------

27/28 Eb/N0 +0.6 dB, S/N -31.6 dB/1Hz, phase 164.1 *Decoded*
28/29 Eb/N0 -2.1 dB, S/N -34.2 dB/1Hz, phase 63.2;
29/30 Eb/N0 -4.7 dB, S/N -36.9 dB/1Hz, phase -52.6;
30/31 Eb/N0 -6.9 dB, S/N -39.0 dB/1Hz, phase -65.3;
31/01 Eb/N0 -9.8 dB, S/N -41.9 dB/1Hz, phase 111.9;

Hawley TX (1816.2 km)
---------------------

27/28 Eb/N0 7.8 dB, S/N -24.3 dB/1Hz, phase -86.3 *Decoded*
28/29 Eb/N0 1.3 dB, S/N -30.8 dB/1Hz, phase -163.5 *Decoded*
29/30 Eb/N0 2.9 dB, S/N -29.2 db/1Hz, phase 55.0 *Decoded*
30/31 Eb/N0 8.7 dB, S/N -23.4 dB/1Hz, phase 2.8 *Decoded*
31/01 Eb/N0 6.5 dB, S/N -25.6 dB/1Hz, phase 151.6 *Decoded*

Forest VA (254.2 km)
--------------------

27/28 Eb/N0 21.2 dB, S/N -10.8 dB/1Hz, phase 115.9 *Decoded*
28/29 Eb/N0 20.4 dB, S/N -11.8 dB/1Hz, phase -14.0 *Decoded*
29/30 Eb/N0 19.4 dB, S/N -12.7 dB/1Hz, phase -124.1 *Decoded*
30/31 Eb/N0 20.0 dB, S/N -12.2 dB/1Hz, phase -143.9 *Decoded*
31/01 Eb/N0 17.6 dB, S/N -14.5 dB/1Hz, phase 12.7 *Decoded*

Phase shifts to apply before stacking
-------------------------------------

27/28: 0 deg
28/29: +118 deg
29/30: +236 deg
30/31: +260 deg
31/01: +257 deg

No significant phase change since the night before.
It almost looks like something has been warming up
and has taken 3 or 4 days to settle down.

--
Paul Nicholson
--