Single spots


KD2OM
 

Wayne,
I didn’t write the query, it is in the demos on wspr.rocks. I found with Phil’s help that the cache needed clearing. After I did that the phantom query showed up. It does seem to work quite well.  I have been checking since I found it and have only found 1 valid call, which was actually a false spot that coincidentally had a real call sign.  The grid was bad as well.  Although you can’t use 4 character grids to determine false spots, so far I haven’t found any false spots with 6 character grids.   10 meters and above I guess it possible to have a valid spot that only one reporter heard. It also could be possible with 2200 and 630 if the transmitter is low power with a poor antenna.
The query is useful but manual checking is still required.

73,
Steve KD2OM 


On Aug 21, 2022, at 22:06, wayne roth <io@...> wrote:

Steve thanks for creating this query.  I was thinking about some single spots that might happen and be valid if the TxGrid matches the actual grid shown on QRZ and I found one such spot of of 10's that I checked and had no QRZ hits.  This was a 10 meter contact, and the band seemed pretty dead when I checked it later.  I searched back 5 weeks and K5UDO only showed up this one time.  I think that this situation is pretty rare though based on the number of calls that didn't have any QRZ or QRZCQ hits.

Local   (y-m-d) TX txGrid RX rxGrid MHz W SNR drift km Az° mode km/W spotQ version
2022-08-21 20:32 K5UDO DN40dh KA7OEI-1 DN31uo 28.126073 10 -27 -1 152 341 2 15 4 WD_3.0.3.3


wayne roth
 
Edited

Steve thanks for creating this query.  I was thinking about some single spots that might happen and be valid if the TxGrid matches the actual grid shown on QRZ and I found one such spot of of 10's that I checked and had no QRZ hits.  This was a 10 meter contact, and the band seemed pretty dead when I checked it later.  I searched back 5 weeks and K5UDO only showed up this one time.  I think that this situation is pretty rare though based on the number of calls that didn't have any QRZ or QRZCQ hits.

Local   (y-m-d) TX txGrid RX rxGrid MHz W SNR drift km Az° mode km/W spotQ version
2022-08-21 20:32 K5UDO DN40dh KA7OEI-1 DN31uo 28.126073 10 -27 -1 152 341 2 15 4 WD_3.0.3.3


KD2OM
 

Personally I believe anything above 30MHz is a waste of electricity :) but I agree, if looking above 10 meters single spots are much more common.
I have been checking over the last few days and have not found a single valid call among the single spots. I have found a few single spots that report as FST4W-300 and -900 but most are reported and type 2 wspr.
It is not difficult to manually check them as there are not many, so far today 462 for all spotters.

Steve

Sent from my iPhone.

On Aug 19, 2022, at 15:18, Glenn Elmore <n6gn@...> wrote:

Perhaps false spots. If you are spotting VHF/UHF WSPR valid single spots are somewhat more common.

I suspect a perfect false spot algorithm isn't possible.


On 8/19/22 13:11, KD2OM wrote:
For interested parties, this query on wspr.rocks shows single spots. Single spots means only one reporter has reported them and only once. They are all false spots.
To use it paste it into the advanced query section and run it from there. It can be saved so that you can access it any time.




Glenn Elmore
 

Perhaps false spots. If you are spotting VHF/UHF WSPR valid single spots are somewhat more common.

I suspect a perfect false spot algorithm isn't possible.

On 8/19/22 13:11, KD2OM wrote:
For interested parties, this query on wspr.rocks shows single spots. Single spots means only one reporter has reported them and only once. They are all false spots.
To use it paste it into the advanced query section and run it from there.  It can be saved so that you can access it any time.


Rob Robinett
 

Thanks Steve,

I got 19 false decodes in the last hour, 5 of them from WD site and 3 of those from Tom WA2TP
So 75% of the bad spots are coming from non-WD users in roughly the proportion of their total spot contrition of 75% of total spots.

Rob

On Fri, Aug 19, 2022 at 12:11 PM KD2OM <steve@...> wrote:
For interested parties, this query on wspr.rocks shows single spots. Single spots means only one reporter has reported them and only once. They are all false spots.
To use it paste it into the advanced query section and run it from there.  It can be saved so that you can access it any time.



***************************************************************************************************************
/* phantom beacons caused by faulty decodes,ie. beacons with single reporters */

and tx_sign in (
 select tx_sign from (
 select tx_sign, count() as spots from wspr.rx
 group by tx_sign
 having spots = 1
 )
)
***************************************************************************************************************** 


73
Steve KD2OM



--
Rob Robinett
AI6VN
mobile: +1 650 218 8896


KD2OM
 

For interested parties, this query on wspr.rocks shows single spots. Single spots means only one reporter has reported them and only once. They are all false spots.
To use it paste it into the advanced query section and run it from there.  It can be saved so that you can access it any time.



***************************************************************************************************************
/* phantom beacons caused by faulty decodes,ie. beacons with single reporters */

and tx_sign in (
 select tx_sign from (
 select tx_sign, count() as spots from wspr.rx
 group by tx_sign
 having spots = 1
 )
)
***************************************************************************************************************** 


73
Steve KD2OM