Re: LF: 8269.9 kHz EbNaut 27/12/17

[DK7FC <selberdenken@posteo.de>]

Hi Markus,

I would agree. The decoder will not put out the correct message just because the man sitting in front of the computer already knows the message.
It is like in WSPR: You won't receive/decode a transmitting station with a higher probability just because you know it is active and know the data (call, loc, dBm). All you can do to obtain a valid decode is applying known data, which means here: Tuning to the right frequency, keeping your PC time accurate and selecting the right mode. And maybe applying an individual noise blanker...
We are doing nothing more in EbNaut. There are just more parameters since it is a very flexible mode...

73, Stefan

Am 28.12.2017 18:10, schrieb Markus Vester:

Hi Dex,

correlation processing is relatively cheap, so no harm done ;-)

> No stacking allowed when message is known.

I politely disagree. A decode made after stacking blindly with constant phase and weights (or weights derived solely from noise level) hasn't made use of a priori information of the correct result. Correlations are ok, but their output should not be used to tweak the phases before stacking. As Paul mentioned earlier, stacking a large enough number of tweaked-phase data sets will eventually produce any desired decode from pure noise. 

Best 73,
Markus

iche Mitteilung-----
Von: Dexter McIntyre W4DEX <dexter.mc@gmail.com>
An: rsgb_lf_group <rsgb_lf_group@blacksheep.org>
Verschickt: Do, 28. Dez 2017 14:32
Betreff: Re: LF: 8269.9 kHz EbNaut 27/12/17

The message was changed.  No stacking allowed when message is known :)  

Sorry for the confusion and wasted processor time.

Will repeat tonight WX premitting.

Dex

On Wed, Dec 27, 2017 at 4:29 PM, Dexter McIntyre W4DEX <dexter.mc@gmail.com> wrote:

New message tonight

3 chars 16K21A CRC20
30 second symbols
Start 22:30 UT

Dex

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