Re: 6m grid false positives in Spot Collector


Al Groff
 



On 6/17/2020 9:13 PM, Peter Dougherty wrote:

[Edited Message Follows]

I'm having a problem with false FT8 positives firing off alerts.
 
I grid chase (and DXCC chase) on 6m. With my cluster connections up and WSJT and JTAlert-x connected, I get frequent hits for stations where the grid information is incorrect. I'm not talking about "gibberish spots" here, but legitimate spots that trigger incorrectly.
 
The source, according to Spot Collector, is my own copy of WSJT-x. There have been numerous examples of a spot arriving via WSJT-X with one (ostensibly) correct grid, but it shows up in the DX Grid column in S.C. with a different grid, causing alerts to sound. I could understand if this was a station I'd worked previously and an old grid was being auto-populated, but this happens even with stations I've never worked before.
 
One such station CQs on FT8 from grid EM31, a grid I have previously worked, confirmed via LoTW, and verified for VUCC credit. The station shows up correctly in WSJT and JTAlert-X, but in Spot Collector it's showing this particular station as EM43, one of only two EM grids I've never worked. This isn't the only circumstance, but since the op in question (AC0RA) is an avid 6m operator with a good signal to me, alerts on his call are frequent.  But with many others the same thing is happening. JTAlert-x/WSJT has the grid correct according to the CQ sent by the originator, but S.C. gets it wrong.

AC0RA is an AVID Rover and has recently been in EM43...

AL, K0VM
 
Now, if this isn't already the case, I would respectfully suggest than any incoming spot for a station previously worked that has grid information populated by the FT8 software, that information needs to override any previous grid info from past QSOs in DXKeeper. Obviously this would be especially needed for Rovers. I have a suspicion that this is already the case, but I wanted to mention it here just in case. But with that said, I'd really like to understand why I'm getting so many false positives.
 
And speaking of false positives, when the inevitable gibberish print from WSJT causes a "need" alert is JTAlert (and subsequently in Spot Collector), is there any way to maybe put in a lookup or truth table, etc, within S.C. so I won't get woken up by a badly interpreted FT8 "spot"?
 
Or some way to say "only alert if X number of "new grid" or "new zone" (etc) spots are received within Y minutes? I'd typically want to set that at 3 within 1 or 2 minutes personally.

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