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Date: Sat, 30 Dec 2017 15:17:26 +0100
From: DK7FC <selberdenken@posteo.de>
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Subject: Re: LF: 8269.9 kHz EbNaut 27/12/17 - decoding ethics?
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I think, in the end the RX station operator and the TX station operator 
must decide for himselfe if he is happy when obtaining a decode with the 
help from others.

Ideally, there is a message announcement (mode | start time | crc | N 
characters | frequency | daily repetition yes or no and when (failed)) 
and the RX station that tries to receive and get a result at some time. 
Then it can make a statement, "I have received the message, it is 
'XYZ'". Then the TX station operator answers "No, sorry" or "Yes, i 
confirm, congrats!". This is the game.

Stacking: The RX operator can see how strong the noise has been on the 
individual days. This is selfe generated information, collected without 
the help of others. Of course it is valid to apply a weighting of the 
individual days into the stacked file.

But for example: In my recent 3 char transmission, the 27th (december) 
has lead to a negative contribution in the develepment of the Eb/N0 in 
the stacked files. But this is only known when knowing the message. So 
if i analyse Alex' files and tell him, "Don't use the 27th in your 
stack, it makes things worse", and if this leads to a successful decode, 
it would not be a valid decode, in my opinion!

Another example: If i would decode a message from Dex, but only with the 
information from Paul, that i have to adjust the phase of the 2nd day by 
-120 deg and the phase of the 3rd day by +90 deg, then this decode would 
not feel valid for me. It wouldn't feel like my decode somehow.

73, Stefan


Am 30.12.2017 12:51, schrieb Markus Vester:
> > So, do ethics accept a decode claim if it is necessary to use 
> published information about the transmit phase to facilitate stacking?
>
> Clearly yes. As you say, information from B describes a property of  
> A's transmitter (e.g. the accurate frequency), which is not related to 
> message content.
>
> > And what about using information published from other sites about 
> the strength and success of the transmission?
>
> Obviously yes, if it's related tro transmitter itself (e.g low tx 
> antenna current, aborted transmissions etc. during certain nights).
>
> In my opinion, this should also extended to propagation-related 
> information (e.g. the phase change between A and B due to transversing 
> the Atlantic). That is more or less equivalent to using other 
> available data for propagation estimates (like Navy-MSK magnitude and 
> phase, electron content, solar data), which is "legal".
>
> > Pushing this further, once the message is published, the repeats can 
> be selected for stacking based on their cross-correlation.
>
> Accorduing to the "guideline", neither B or C may make use of 
> the actual noise instance at receiver C to preselect C's data, 
> because that could bias the noise statistics at C towards a decode. So 
> the knowledge of A's message and C's noise should not be combined. 
> Clearly, C may not apply knowledge of the message to 
> make correlations with his own noise, and use them to weight or 
> preselect his data.
>
> On the other hand, in my opinion correlation results from B (based on 
> propagation A-B and noise at B) could "legally" be used for stacking 
> by C. This implicitly assumes that noise instances at B or C are 
> uncorrelated, so applying B's weights at C won't bias C's noise 
> towards the correct message.
>
> Howecver theoretically the noise at B and C could be correlated, for 
> example if the dominant noise source is a very localized thunderstorm, 
> affecting both B and C. Then B has indirect access to noise at C, 
> and application of B's correlation results could bias C's noise 
> statistics. Depending on phase differences, this could increase or 
> decrease the likelyhood of a correct decode at C. In practice, given 
> the size and movement of thunderstorms acompared to the wavelength, 
> I would not expect a large noise correlation between far-spaced 
> receiver sites (unless for certain special geometries, e.g. all three 
> stations and noise sources arranged in-line on the same great-circle). 
> Thus in my opinion, the application of B's correlations at C should 
> not be generally forbidden.
>
> So like with many questions in ethics, the answers are not always 
> purely black or white. I have to say I'm glad Ive become an engineer 
> rather than a lawyer ;-)
>
> Best 73,
> Markus (DF6NM)
>
> -----Ursprüngliche Mitteilung-----
> Von: Paul Nicholson <vlf0403@abelian.org>
> An: rsgb_lf_group <rsgb_lf_group@blacksheep.org>
> Verschickt: Fr, 29. Dez 2017 19:29
> Betreff: Re: LF: 8269.9 kHz EbNaut 27/12/17
>
> Dex wrote:
>
> > New message tonight [27th]
>
> > 3 chars 16K21A CRC20
> > 30 second symbols
> > Start 22:30 UT
>
> Decoding from 8269.9 Hz, 2017-12-XX_22:30,+27900
> vtfilter -h bp,f=8270,w=3000
> vtblank -a12 -d0 -t100
> ebnaut -dp16K21A -r1 -S30 -k20 -N3 -PU -L500000 -v
>
> Todmorden (6194 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*
>
> 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;
>
> Fails to decode with stacking, Eb/N0 -5.0 dB due to
> phase change.
>
> 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;
>
> 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;
>
> 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*
>
> 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*
>
> All the rx sites show a similar phase change between the two
> nights, even Warsaw with the very weak signal.
>
> So, do ethics accept a decode claim if it is necessary to use
> published information about the transmit phase to facilitate
> stacking?
>
> One might argue that knowledge of the tx phase is no different
> to knowing the tx frequency and start time. Such knowledge
> does not bypass any propagation.
>
> And what about using information published from other sites
> about the strength and success of the transmission?
>
> A problem with stacking is the number of permutations as the
> number of repeats increases. Eg with four repeats, there are:
>
> One run with all four;
> Four runs with one repeat dropped;
> Six runs with two repeats dropped;
> Four runs with single repeats;
>
> 15 runs altogether and the operator is obliged to accept the
> strongest looking decode out of all of them. Each of the
> 15 runs has the chance of throwing up a false decode which
> will beat the correct decode. Therefore, knowledge that a
> particular repeat performed poorly at other sites allows you
> to drop that one with no cost in terms of false decodes.
>
> Pushing this further, once the message is published, the
> repeats can be selected for stacking based on their cross-
> correlation. You might for example have 10 repeats and be
> able to get a decode from the best 5, Without that knowledge
> you would need 252 full runs of the decoder to go through all
> permutations of 5 out of 10 repeats, surely enough to suffer
> a stronger false decode.
>
> --
> Paul Nicholson
> --
>

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I think, in the end the RX station operator and the TX station operator
must decide for himselfe if he is happy when obtaining a decode with
the help from others. <br>
<br>
Ideally, there is a message announcement (mode | start time | crc | N
characters | frequency | daily repetition yes or no and when (failed))
and the RX station that tries to receive and get a result at some time.
Then it can make a statement, "I have received the message, it is
'XYZ'". Then the TX station operator answers "No, sorry" or "Yes, i
confirm, congrats!". This is the game.<br>
<br>
Stacking: The RX operator can see how strong the noise has been on the
individual days. This is selfe generated information, collected without
the help of others. Of course it is valid to apply a weighting of the
individual days into the stacked file.<br>
<br>
But for example: In my recent 3 char transmission, the 27th (december)
has lead to a negative contribution in the develepment of the Eb/N0 in
the stacked files. But this is only known when knowing the message. So
if i analyse Alex' files and tell him, "Don't use the 27th in your
stack, it makes things worse", and if this leads to a successful
decode, it would not be a valid decode, in my opinion!<br>
<br>
Another example: If i would decode a message from Dex, but only with
the information from Paul, that i have to adjust the phase of the 2nd
day by -120 deg and the phase of the 3rd day by +90 deg, then this
decode would not feel valid for me. It wouldn't feel like my decode
somehow.<br>
<br>
73, Stefan<br>
<br>
<br>
Am 30.12.2017 12:51, schrieb Markus Vester:
<blockquote
 cite="mid:160a7431cfd-171d-50ee@webjas-vac077.srv.aolmail.net"
 type="cite">
  <div
 style="font-size: 10pt; font-family: arial,helvetica,sans-serif; color: black;">
  <div id="AOLMsgPart_2_2b1c7702-d6e0-4f3e-84eb-a6b8f00070f2">
  <div
 style="color: black; font-family: arial,helvetica,sans-serif; font-size: 10pt;">
  <div id="AOLMsgPart_2_13f56b23-0547-4282-9450-871768c1186d">
  <div
 style="color: black; font-family: arial,helvetica,sans-serif; font-size: 10pt;">
  <div
 style="color: black; font-family: arial,helvetica,sans-serif; font-size: 10pt;">&gt;
So, do ethics accept a decode claim if it is necessary to use published
information about the transmit phase to facilitate stacking?<br>
  <br>
Clearly yes. As you say, information from B describes a property of 
A's transmitter (e.g. the accurate frequency), which is not related to
message content.<br>
  <br>
&gt; And what about using information published from other sites about
the strength and success of the transmission?<br>
  <br>
Obviously yes, if it's related tro transmitter itself (e.g low tx
antenna current, aborted transmissions etc. during certain nights).<br>
  <br>
In my opinion, this should also extended to propagation-related
information (e.g. the phase change between A and B due to transversing
the Atlantic). That is more or less equivalent to using other available
data for propagation estimates (like Navy-MSK magnitude and phase,
electron content, solar data), which is "legal".<br>
  <br>
&gt; Pushing this further, once the message is published, the repeats
can be selected for stacking based on their cross-correlation. <br>
  <br>
Accorduing to the "guideline", neither B or C may make use of
the actual noise instance at receiver C to preselect C's data,
because that could bias the noise statistics at C towards a decode. So
the knowledge of A's message and C's noise should not be combined.
Clearly, C may not apply knowledge of the message to
make correlations with his own noise, and use them to weight or
preselect his data. <br>
  <br>
On the other hand, in my opinion correlation results from B (based on
propagation A-B and noise at B) could "legally" be used for stacking by
C. This implicitly assumes that noise instances at B or C are
uncorrelated, so applying B's weights at C won't bias C's noise towards
the correct message.<br>
  <br>
Howecver theoretically the noise at B and C could be correlated, for
example if the dominant noise source is a very localized thunderstorm,
affecting both B and C. Then B has indirect access to noise at C,
and application of B's correlation results could bias C's noise
statistics. Depending on phase differences, this could increase or
decrease the likelyhood of a correct decode at C. In practice, given
the size and movement of thunderstorms acompared to the wavelength,
I would not expect a large noise correlation between far-spaced
receiver sites (unless for certain special geometries, e.g. all three
stations and noise sources arranged in-line on the same great-circle).
Thus in my opinion, the application of B's correlations at C should not
be generally forbidden. <br>
  <br>
So like with many questions in ethics, the answers are not always
purely black or white. I have to say I'm glad Ive become an engineer
rather than a lawyer ;-)<br>
  <br>
Best 73,<br>
Markus (DF6NM)<br>
  <br>
-----Ursprüngliche Mitteilung----- <br>
Von: Paul Nicholson <a class="moz-txt-link-rfc2396E" href="mailto:vlf0403@abelian.org">&lt;vlf0403@abelian.org&gt;</a><br>
An: rsgb_lf_group <a class="moz-txt-link-rfc2396E" href="mailto:rsgb_lf_group@blacksheep.org">&lt;rsgb_lf_group@blacksheep.org&gt;</a><br>
Verschickt: Fr, 29. Dez 2017 19:29<br>
Betreff: Re: LF: 8269.9 kHz EbNaut 27/12/17<br>
  <br>
  </div>
Dex wrote:<br>
  <br>
&gt; New message tonight [27th]<br>
  <br>
&gt; 3 chars 16K21A CRC20<br>
&gt; 30 second symbols<br>
&gt; Start 22:30 UT<br>
  <br>
Decoding from 8269.9 Hz, 2017-12-XX_22:30,+27900<br>
vtfilter -h bp,f=8270,w=3000<br>
vtblank -a12 -d0 -t100<br>
ebnaut -dp16K21A -r1 -S30 -k20 -N3 -PU -L500000 -v<br>
  <br>
Todmorden (6194 km)<br>
-------------------<br>
  <br>
27/28 Eb/N0 +9.2 dB, S/N -22.9 dB/1Hz, phase -140.9 *Decoded*<br>
28/29 Eb/N0 +5.4 dB, S/N -26.7 dB/1Hz, phase 108.7 *Decoded*<br>
  <br>
Bielefeld (6917.7 km)<br>
---------------------<br>
  <br>
27/28 Eb/N0 -2.6 dB, S/N -34.7 dB/1Hz, phase 71.2;<br>
28/29 Eb/N0 -2.3 dB, S/N -34.4 dB/1Hz, phase -45.2;<br>
  <br>
Fails to decode with stacking, Eb/N0 -5.0 dB due to<br>
phase change.<br>
  <br>
Warsaw (7681.3 km)<br>
------------------<br>
  <br>
27/28 Eb/N0 -7.4 dB, S/N -39.6 dB/1Hz, phase 143.3;<br>
28/29 Eb/N0 -11.5 dB, S/N -43.7 dB/1Hz, phase 85.6;<br>
  <br>
Cumiana (7173.4 km)<br>
-------------------<br>
  <br>
27/28 Eb/N0 +0.6 dB, S/N -31.6 dB/1Hz, phase 164.1 *Decoded*<br>
28/29 Eb/N0 -2.1 dB, S/N -34.2 dB/1Hz, phase 63.2;<br>
  <br>
Hawley TX (1816.2 km)<br>
---------------------<br>
  <br>
27/28 Eb/N0 7.8 dB, S/N -24.3 dB/1Hz, phase -86.3 *Decoded*<br>
28/29 Eb/N0 1.3 dB, S/N -30.8 dB/1Hz, phase -163.5 *Decoded*<br>
  <br>
Forest VA (254.2 km)<br>
--------------------<br>
  <br>
27/28 Eb/N0 21.2 dB, S/N -10.8 dB/1Hz, phase 115.9 *Decoded*<br>
28/29 Eb/N0 20.4 dB, S/N -11.8 dB/1Hz, phase -14.0 *Decoded*<br>
  <br>
All the rx sites show a similar phase change between the two<br>
nights, even Warsaw with the very weak signal.<br>
  <br>
So, do ethics accept a decode claim if it is necessary to use<br>
published information about the transmit phase to facilitate<br>
stacking?<br>
  <br>
One might argue that knowledge of the tx phase is no different<br>
to knowing the tx frequency and start time. Such knowledge<br>
does not bypass any propagation.<br>
  <br>
And what about using information published from other sites<br>
about the strength and success of the transmission?<br>
  <br>
A problem with stacking is the number of permutations as the<br>
number of repeats increases. Eg with four repeats, there are:<br>
  <br>
One run with all four;<br>
Four runs with one repeat dropped;<br>
Six runs with two repeats dropped;<br>
Four runs with single repeats;<br>
  <br>
15 runs altogether and the operator is obliged to accept the<br>
strongest looking decode out of all of them. Each of the<br>
15 runs has the chance of throwing up a false decode which<br>
will beat the correct decode. Therefore, knowledge that a<br>
particular repeat performed poorly at other sites allows you<br>
to drop that one with no cost in terms of false decodes.<br>
  <br>
Pushing this further, once the message is published, the<br>
repeats can be selected for stacking based on their cross-<br>
correlation. You might for example have 10 repeats and be<br>
able to get a decode from the best 5, Without that knowledge<br>
you would need 252 full runs of the decoder to go through all<br>
permutations of 5 out of 10 repeats, surely enough to suffer<br>
a stronger false decode.<br>
  <br>
--<br>
Paul Nicholson<br>
--<br>
  <br>
  </div>
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  </div>
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  </div>
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