[CQ-Contest] Understanding the dynamic error free RBN algorithm - The DR1A case

Wed Jul 17 22:32:48 EDT 2013

I forgot to mention.
The small excel file with all the DR1A data is here
http://www.qsl.net/c/ct1boh//dl/dr1a_40_cqww12.xlsx

73 José Nunes
CT1BOH

On Thu, Jul 18, 2013 at 3:26 AM, José Nunes CT1BOH <ct1boh at gmail.com> wrote:

> I received several e-mails regarding the understanding of the dynamic
> error free RBN.
> In order to explain this graphically I will use the DR1A case from CQWW CW
> 2012 on 40 meters.
>
> DR1A was the most spotted station on 40 meters.
> DR1A was also busted many times and those busted spots were sent to the RBN
>
> Overall there were 8223 spots coming from the real DR1A on the bands:
>
> 8114 DR1A spots
>
> 109 bust spots of DR1A with the following occurrences - DR1S (24), NR1A
> (15), DR1T (14), IR1A (11), DR1I (8), DM1A (8), DR4A(7), MR1A (4), KR1A
> (4), LR1A (3), DR2A (2), DK1AX ( 2), DR1U (2), DD1A (1), DR1AE (1), XR1A
> (1), DR1N (1) and HR1A (1)
>
>
> As you can see RBN skimmers are very "creative" when it comes to busting
> good calls. But bear in mind that Skimmer is more accurate than humans.
> Humans are even more creative when it comes to busting calls, as can be
> seen in CQWW rpt log checking reports.
>
> CT1BOH dynamic error free RBN algorithm catches this dynamic flawlessly.
>
> CT1BOH algorithm output for all these 8223 spots is the following:
>
> Good Call                               7643      92.9%
> Good call, New Frequency       468      5.7%
> DR1A Busts                              109       1.3%
> ?Spots                                  2           0.0%
> Busted                                  1          0.0%
>
>
> Let's put only the good spots in a graph. Click the links below to see.
> http://www.qsl.net/c/ct1boh//dl/good.png
>
> The X axis shows the 48 hours of the contest from minute 1 (00:00
> Saturday) until minute 2880 (23:59 sunday).
> The Y axis shows frequency.
>
> The scattered dots in the first three hours is DR1A trying to find a good
> run frequency. If I zoom only for the first three hours this becomes more
> clear
> http://www.qsl.net/c/ct1boh//dl/first3.png
>
> Let's go back to the original graph with the good spots during the 48
> hours, and add the 109 DR1A Busts that Skimmers generated
> http://www.qsl.net/c/ct1boh//dl/goodandbusts.png
> CT1BOH algorithm catches all the busted spots and can filter them out of
> the network
>
> Let's now add to the graph the "Good call, New frequency?" spots. By now
> you know that these spots are the first and the second spots when a new run
> frequency is established (these are good spots - I know they were 49 spots
> out of the 468) and the true bad frequency spots from uncalibrated skimmers
> (I know they are 419 spots)
> http://www.qsl.net/c/ct1boh//dl/goodbustgnf.png
>
> Let's just go a bit deeper in this graphical analysis.
> Where are all these bad frequency spots coming from?
> 93 different skimmer from around the world spotted DR1A or busted DR1A
> call.
> But not all of them were uncalibrated.
> http://www.qsl.net/c/ct1boh//dl/skimmers.png
>
> If I remove from the graph the  six uncalibratted skimmers (MM1PTT/P,
> F5MUX, HA6PX, DJ4DI, G4HYG, W2RDX)
> The graph goes from this http://www.qsl.net/c/ct1boh//dl/goodbustgnf.png
> into this http://www.qsl.net/c/ct1boh//dl/remove6skimmers.png
>
> Amazing isn't it. Just removing six uncalibratted skimmer makes a huge
> difference.
> One final graph. If we now look at all the spots from those six skimmers
> http://www.qsl.net/c/ct1boh//dl/datafrom6skimmers.png
> we clearly see, that they still produce a lot of good spots. They just
> have to fix that IQ image N4ZR explained in his post.
> Until then the dynamic error free RBN algorithm will easily filter them
> out on the spot.
>
> By now, I hope I have explained how effective a dynamic free RBN algorithm
> works.
> This algorithm is so effective because the network is so big that the good
>  spots will always outnumber the bad spots.
>
> Also I would like to explain the price of running this algorithm
> The price is the first two good spots in a run until the third comes to
> validate it is a good call.
>
> In the case of DR1A the price is 49 spots that are filtered out so that we
> can drop 520 bad spots
> Because the network is so big, this price is negligible, i.e. even if we
> drop the first two spots of a run, chances are that the third spot will be
> in the same minute.
>
> To answer UA9CDC:
> Parasitic AM Modulation will be much less spotted that the good signal.
> The good signal will outnumber them, and since they are +/- 1.5 KHz away
> they will be dropped as "Good call, New Freq?" spot
>
> Second and third harmonic will be spotted as good, just like they are
> today. These are very, very, insignificant cases in the overall number of
> spots. The algorithm could be enhanced to try to predict these cases, but I
> don't advice doing it. I'd rather have a false positive than a false
> negative.
>
> No problem with MM stations. The algorithm runs per band. My code was just
> for one band for demonstration purposes.
>
> I understand VE7CC-1 just implemented his version of the dynamic erro free
> RBN. Also I understand N1MM and AR cluster is also implemented.
> Soon, busted spots ans wrong frequency spots will be a thing of the past
> from this extraordinary tool  - Reverse Beacon Network
>
> 73 José Nunes
> CT1BOH
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> --
> José Nunes
> CONTEST CT1BOH - http://www.qsl.net/ct1boh
>

-- 
José Nunes
CONTEST CT1BOH - http://www.qsl.net/ct1boh