The new checking system has just worked. JA8SCD was reported by SV8CS
at nearly 10,000km on 136kHz whilst the JA was using a dummy load.
This is plainly a false decode, but the new software showed "Deep
Search ??" to indicate this should be viewed with caution.
Mike, G3XDV
===========
> 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" <[email protected]>
> Sent: Saturday, January 10, 2015 11:09 AM
> To: <[email protected]>; <[email protected]>
> 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
> > ===========
> >
>
>
>
> -----
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