Message-ID: <6F0B87EF8D1F4AA0AF70320B15F3E120@AGB>
From: "Graham" <g8fzk@g8fzk.fsnet.co.uk>
To: <rsgb_lf_group@blacksheep.org>
References: <54B10878.10172.535233@mike.dennison.ntlworld.com>
In-Reply-To: <54B10878.10172.535233@mike.dennison.ntlworld.com>
Date: Sat, 10 Jan 2015 15:26:44 -0000
MIME-Version: 1.0
Importance: Normal
Subject: Re: LF: Opera improving
Content-Type: text/plain;
	format=flowed;
	charset="iso-8859-1";
	reply-type=original
Content-Transfer-Encoding: 7bit
Sender: owner-rsgb_lf_group@blacksheep.org
Precedence: bulk
Reply-To: rsgb_lf_group@blacksheep.org
Status: O

Mike ,

Power gain is  close  to  6  dB  , so  that's  a  times  four  over  the 
standard   Opera  data  decode limits

Any  numerically  processed  data   mode  is  based  solely on  Guess work, 
just that  Guess   work  is   translated  by  decision  making  and   fuzzy 
logic in to a  reproduction  of the  original  message

Modes like  opera / ros / olivia  etc  use  algorithms  to  compress  and 
extract the  call , hence  opera  data  miss  decodes, 'have'   a  normal 
call  profile  , but  are  not  valid . simple   rtty  just  produce's  near 
random  data

In the  case  of  Marcus's  opds ,  your  are  presented  with  a set of 
values ,  a little  deeper ,  these  will  of  been  constructed  from  a 
layer  of  fuzzy logic , as  are  the  dsp  decisions  in  opera  etc ,  in 
the  case  of Opera dynamic ,  the  outputs  from  the  data  decoder   and 
the  'search'  detector  are  assimilated by  a another  layer  of  decision 
making  logic

The  command  structure ,  then  decides  at what point  the  decoder  has 
failed  and  the  results  from the  detector  are  evaluated , the dynamic 
call  lists  are  maintained , via tx  web  beacon  and  1+1  quality check 
of  decoded  calls

Table  is  held  for  8 days  We did  have  3 days  as  the  original  cycle 
time ,  however ,  as   activity on  136/477  tends  to  follow  the  7 day 
week  pattern  , stations  using  pic/pi/U3  and  other  Tx  systems ,  with 
no  web-beacon  would  need  to  be decoded  by  2  stations  using 
op32/op8  on there  first  pass, to  catch  the  second

The show go's on ;)

73-Graham
G0NBD


--------------------------------------------------
From: "Mike Dennison" <mike.dennison@ntlworld.com>
Sent: Saturday, January 10, 2015 11:09 AM
To: <rsgb_lf_group@blacksheep.org>; <rsgb_lf_group@yahoogroups.co.uk>
Subject: LF: Opera improving

> There is a British saying "Don't throw the baby out with the
> bathwater". Amongst the criticism of false decodes (which I have been
> part of), we must not forget that Opera is now more sensitive - the
> equivalent of doubling everybody's power - which must be good. This
> has led to many more good DX decodes.
>
> Now, in response to suggestions from users, the writers have modified
> the program to flag up decodes that might be suspicious, which is
> what OPDS does (but in a different way). Used with caution, this will
> address most of the problems experienced with the launch version.
>
> The controversial PDF file has also been dropped from the zip file.
>
> Deep Search, originally developed by DF6NM, has always involved
> "guesswork", and therefore needs to be viewed with caution. In short
> it compares a list of known active stations (again Op and OPDS does
> this differently) with what might be described as 'partial decodes'
> and finds the best match. Anyone who has worked DX, operated in a
> contest or used QRSS will be familiar with that technique. Indeed
> that is how the human brain works all of the time - it matches what
> its sees with a huge look-up table of past experiences, which is why
> we see faces in clouds (a false decode). The key is to use our
> experience to work out what is true and what is false.
>
> I would suggest three more improvements:
>
> My understanding is that callsigns in the 'look-up table' are dropped
> after 8 hours. Reducing this period might help.
>
> For those who don't like Deep Search, there should be an 'off'
> switch, perhaps in the existing Deep Search menu. The 'on' swtch
> might come with a "use with caution" message.
>
> Used carefully, the new v1.5.6 should be a great improvement on the
> (pre Deep Search) version 1.5.4.
>
> Mike, G3XDV
> ===========
>