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To: rsgb_lf_group@blacksheep.org
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From: Markus Vester <markusvester@aol.com>
Message-Id: <8D20EAD7BAE8F0F-D5C-1AF56@webmail-va032.sysops.aol.com>
Date: Wed, 4 Feb 2015 11:22:09 -0500
Subject: Re: LF: OPdynamic false T/A spot
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Status: O

For my LF opds-32 detector, I currently have 49 entries in the 
searchlist: https://dl.dropboxusercontent.com/u/26404526/callsloc.txt

I am regularly inspecting the output for likely false positives, which 
are then highlighted by a question mark at the end of the line. Over 
several months, their rate of occurrence has been on the order of 2 per 
week. Most are associated either with one of the many spurious 
carriers, or Opera transmitters which had not yet been included in the 
list at the time.

Best 73,
Markus (DF6NM)

-----Ursprüngliche Mitteilung-----
Von: jrusgrove <jrusgrove@comcast.net>
An: rsgb_lf_group <rsgb_lf_group@blacksheep.org>
Verschickt: Mi, 4 Feb 2015 3:38 pm
Betreff: Re: LF: OPdynamic false T/A spot

Mike

We agree that OPdynamic spots with ?? should not be uploaded ... but 
that isn't the case at the
moment. The R7NT OPdynamic spot of WD2XNS (10 hours after the 
transmitter was turned off) shows up
right along with all of the genuine spots - it's indistinguishable. 
This is a problem and seriously
undermines the credibility of OPERA.

As for callsigns only being held for a short time  in the deep search 
list ... I going to have to
disagree. While it may put a bandaid on the serious OPdynamic problem 
with false spots it makes it
far too easy on the correlation detector. It's possible that only one 
callsign might be on the list!
I'd much rather have the DF6NM system where all possible stations 
(about 30 stations last time I
checked) are present all the time. The game sure seems a lot less 
'rigged' when the correlation
detector has to analyze 30 callsigns rather than just one or maybe two.

When you think about it, the DF6NM system must be vastly superior to 
OPdynamic ... considering the
minute number of false spots with 30 callsigns to pick from. OPdynamic 
produces far more false spots
and it only has a few callsigns to choose from at any time. Reducing 
OPdynamics choices even further
(by shortening the 'holding time') would reduce false spots ... but 
that just points up how inferior
OPdynamic really is. Not a good solution in my opinion.

Jay W1VD  WD2XNS  WE2XGR/2


----- Original Message -----
From: "Mike Dennison" <mike.dennison@ntlworld.com>
To: <rsgb_lf_group@blacksheep.org>
Sent: Wednesday, February 04, 2015 5:50 AM
Subject: Re: LF: OPdynamic false T/A spot


> Jay,
>
> I am inclined to agree with you, but almost all of the Deep Search
> spots that have no question marks are genuine. If at all possible,
> spots =with= the question marks should not be uploaded to PSK
> Reporter as most are false.
>
> Also, I suggested early on that callsigns are on the database for too
> long, and should only be a couple of hours after the last known
> 'real' Op decode.
>
> These steps would of course slightly reduce the number of genuine
> weak signals decoded/reported but the result would be far more
> accurate and still show a useful increase in sensitivity over Op.
>
> Mike, G3XDV
> ==========
>