[Moon] wsjt-cw

[DF2ZC]

Hello All,

Klaus writes of a "difficulty" of receiving the "address information" for
the predefined set of callsign combinations and says it equals the
difficulty to receive two arbitraty characters.

Actually, he does not mean "difficulty" as we usually understand it, he
means the 'amount of information received'. This 'amount of information
received' indeed is roughly equal in both cases. Only, this has nothing to
do with how "difficult" it was to receive the signal over the air or whether
only parts of the callsign were copied. It applies at FULL copy of all
transfered dits and dahs, of all bits over the air.

BTW, in a sked (CW, JT65DS, SSB, whatsoever) the "difficulty" (as Klaus
describes it) to receive the callsign data etc is way less than the
difficulty to receive a single arbitrary character. Why? Because all
information is already present at either side, be on hard disk or in the
grey cells between the ears.

vy 73 Bernd DF2ZC (JO30RN)
www.df2zc.de

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-----Original Message-----
From: moon-bounces at moonbounce.info [mailto:moon-bounces at moonbounce.info] On
Behalf Of Klaus DJ5HG
Sent: Samstag, 19. April 2008 15:59
To: moon at moonbounce.info
Subject: Re: [Moon] wsjt-cw




Hello Gio, hello all,


let me comment your mail:

> Hi Graham, I agree with your considerations. 
> I would like to add that a verification is possible also in JT65. If 
> you decode a cq with the help of deep search and you are in doubt even 
> if the decode probability is labeled 10, a verification will follow. 
> In fact, at this point one answers with both calls. If the decoded 
> call is not correct, the other station will continue with cq.
> If she answers, this means his call is correct. I suppose that also in 
> a cw qso a false decode can happen and I suppose that the station 
> calling cq will do something similar until the code is correct. In a 
> sked the situation is the same. So, also in a JT65 qso all letters are 
> copied, not the first time, but cw rules do not say this.

JT65 is a fine mode as long as the RS or the KV-decoders are used. DS is
based on a completely other interpretation. 
It does not use letters or symbols as JT65, it only knows some 1000
different messages and the corresponding physical signals. You could encode
the same number of Chinese symbols into these signals, or you could use
images or long texts like complete books, all stored on your HD. The DS
decoder simply says which of the signals fits best and then displays on the
screen what you have associated on your computer with the signal - a Chinese
letter or an image or a complete book. What you really have received, only
is the number of the signal, not the image or the book or the both calls
displayed by JT65.

Unfortunately, the total number of signals used in DS is not sufficient to
encode two arbitrary callsigns, it just can encode two characters. So the
difficulty to receive the address information for the displayed message is
the same as to receive two characters. 

> So we should clarify the rules of a digital qso, but with different 
> wording they will be applicable also to cw, they will not be a 
> separate set of rules.
> Thank you for the serene and civil words you employed in explaining 
> your opinion.
> 73, Gio IK1UWL

Yes ok Gio!


73,

Klaus




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