To: rsgb_lf_group@blacksheep.org
References: <5f631e31-6572-0ac8-cc37-57e692fbb009@abelian.org>
 <160667f3c23-1723-5142e@webjas-vac249.srv.aolmail.net>
 <CANA3B6VUGi1AJr7UxMjAT4KWh0KYzgshvD1Q7zdzJzMQv8dKfA@mail.gmail.com>
 <14d7961f-5f5c-9c72-c4bc-19d4ae748d0a@abelian.org>
 <CANA3B6UtPG43zKu1_fzYSaB2nVHwNqGiBi8m+nM+MX0YJA=TGw@mail.gmail.com>
 <16a0a750-e7da-6ed1-633e-3ac6a63f49e2@abelian.org>
 <1a001780-e183-350f-7a00-23e8a6d1202a@abelian.org>
 <b9b81dac-bd11-3bde-2882-645159e27009@abelian.org>
 <CANA3B6XUqSkGh3GYraB=q6UUg2YbHzTTPbgo1VoqnakE1VDLVw@mail.gmail.com>
From: Paul Nicholson <vlf0403@abelian.org>
Message-ID: <914e98a2-78e2-cc75-e1d4-fb36366906c4@abelian.org>
Date: Thu, 21 Dec 2017 08:56:43 +0000
User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:52.0) Gecko/20100101
 Thunderbird/52.3.0
MIME-Version: 1.0
In-Reply-To: <CANA3B6XUqSkGh3GYraB=q6UUg2YbHzTTPbgo1VoqnakE1VDLVw@mail.gmail.com>
Content-Language: en-US
Subject: Re: LF: EbNaut test at 8270.00332 from JN64bw
Content-Type: text/plain; charset=utf-8; format=flowed
Content-Transfer-Encoding: 8bit
Sender: owner-rsgb_lf_group@blacksheep.org
Precedence: bulk
Reply-To: rsgb_lf_group@blacksheep.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
--