de JF2IWL
I well understand circumstances of RBN. Thank you Pete.
and I am relieved my OCXO works good by Tim's report. Thank you.
> Is your OCXO GPS-disciplined, or just periodically recalibrated? OK if
> we add yours to our list of standard stations?
As I report to Pete the other day,. My OCXO does not look up GPS.
(Hand made by my friend, just only 10MHz OCXO x 12.5 PLL)
When I reform OCXO looking GPS in a future,Let me join 10Hz Club.
I will continue watching accuracy of my SDR
Thank you.
Dai JF2IWL
On Mon, 5 Oct 2015 08:12:53 -0400
Pete Smith N4ZR <n4zr@contesting.com> wrote:
> Hello, Dai. The way the RBN is supposed to work is this: There is a
> relatively small group of Skimmers that are known to use highly accurate
> frequency standards - typically GPS-disciplined oscillators - which are
> designated as primary standard stations for skew comparisons. but
> because HF propagation won't permit any small number of standards to be
> used worldwide, the system also designates Skimmers on each band that
> are agreeing with the primary standards, as temporary standards of
> comparison for a short period of time. This list is constantly changing.
>
> We've noticed this phenomenon of false skew warnings since early in the
> life of the system, but have never been able to track down the cause.
> It's really not a "red card", just an advisory. The data are useful to
> us, because often they do point to Skimmers that are having problems so
> that we can advise the operators on how to improve their calibration. I
> myself get these "phantom" warnings occasionally , but typically they
> appear and arequickly gone.
>
> Is your OCXO GPS-disciplined, or just periodically recalibrated? OK if
> we add yours to our list of standard stations?
>
> 73, Pete N4ZR
> Download the new N1MM Logger+ at
> <http://N1MM.hamdocs.com>. Check
> out the Reverse Beacon Network at
> <http://reversebeacon.net>, now
> spotting RTTY activity worldwide.
> For spots, please use your favorite
> "retail" DX cluster.
>
> On 10/3/2015 9:06 PM, Dai NAGAKURA wrote:
> > Dear members de JF2IWL
> >
> > This talking may not fit on this reflector.
> > I read interesting Lee's busted callsign data as one of RTTY Skimmer.
> >
> > Then,, How is " Frequensy Busted spots" ?
> > I was issued a red card by aggregator many times in WW RTTY
> > " your sdr skews 0.7kHz on 15m "
> > But my QS1R with OCXO(0.5ppm/10year)
> > captures right frequency.all the time.
> >
> > I call it "Skew Dancing", It occurs big contests
> > Why this phenomenon occurs ?
> >
> > My spot may be jumbled by inaccurate skimmers.
> > I heard that skew of skimers is calculated by some standard skimer.
> > but it is not true.
> >
> > Can these subject be analyzed by actual data like Lee's?
> > Hope skimmers calibrate SDR and provide right spots.
> >
> > Dai JF2IWL
> >
> >
> >
> >
> >
> > On Wed, 30 Sep 2015 19:19:01 -0600 (MDT)
> > Lee Sawkins<ve7cc@shaw.ca> wrote:
> >
> >> These links may be interesting to some of you. These are the typical
> >> rejected spots of any CC Cluster.
> >>
> >> RTTY skimmer spots are considered valid if spotted by ONE Skimmer. RTTY
> >> Skimmers are generally more accurate than CW and there are simply not
> >> enough of them to use 2 or more Skimmers to validate them. CW spots are
> >> valid if spotted by 2 or more Skimmers.
> >>
> >> Here is the list of dropped Skimmer spots by the VE7CC-1 cluster.
> >> If you connect to the RBN directly, you will receive all these spots as
> >> well as the good ones.
> >>
> >> Many times there are two calls in succession that are dropped for RTTY
> >> calls. I am receiving data from both the RBN and DL4RCK for redundancy.
> >> Usually they both spot the same RTTY calls.
> >>
> >> Most columns are self explanatory.
> >>
> >> The number directly before a skimmer call is a quality number. It is the
> >> number of times a call has been detected as correct minus the number of
> >> times it is busted. When the number decreases below 5, it is no longer
> >> considered valid. If the active call has not been spotted in 12 minutes it
> >> is also no longer considered valid. In one place, for 9A1A the quality
> >> number is over 2000. This means 9A1A has been spotted over 2000 times on
> >> the same frequency!
> >> "Sysop added" means I have manually added a call to the list because it is
> >> busted all the time and is never good.
> >>
> >> http://www.bcdxc.org/ve7cc/ccc/Busted-26-Sep-2015.txt
> >> http://www.bcdxc.org/ve7cc/ccc/Busted-27-Sep-2015.txt
> >>
> >> Lee
> >> _______________________________________________
> >> RTTY mailing list
> >> RTTY@contesting.com
> >> http://lists.contesting.com/mailman/listinfo/rtty
>
--
Dai NAGAKURA <ndai@cameo.plala.or.jp>
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