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6m grid false positives in Spot Collector


Peter Dougherty
 
Edited

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.
 
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.


Dave AA6YQ
 

+ AA6YQ comments below

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.

+ If you're using JTAlert, then JTAlert is the source of the gird information.


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 DX Base it's showing this particular station as EM43, one of only two EM grids I've never worked.

+ I can't help you with DX Base, Peter.


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.

+ SpotCollector receives spots from JTAlert, but also from your other spot sources. If you have SpotCollector configured to capture location information from spot notes, then it's possible that a Spot Database entry created by JTAlert with one grid square gets updated with a different grid square from a subsequent cluster spot. To see if this is happening,

1. enable "Record individual spot information" (Configuration window, "Spot Database" tab)

2. when encounter a Spot Database Entry with what appears to be an incorrect grid square, right-click it, and select "Display spots of"; a window bearing all spots of the Entry's station will appear.


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.

+ Most users do not have a computer fast enough query their log for previous QSOs with each incoming spot.


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"?

+ No:

1. there is no database that specifies an award-accurate grid square for amateur radio station (DXLab's USAP database only contains callsigns issued by the US FCC, and the grid squares are not award-accurate because they are computed from the centroid of the station's zip code)

2. even if such a database existed, some stations operate from non-home locations


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.

+ The mechanism required to implement this would require significant development effort, but most users want to be immediately notified if a needed station might be QRV and thus would not utilize it.

73,

Dave, AA6YQ


Peter Dougherty
 

I meant Spot Collector, of course. I had been chatting about my days with DX Base with a friend earlier tonight and I typed that unintentionally. I have corrected it in my original question, above.

I will test this out tomorrow (or whenever the band opens enough to see the usual flood of spots).

If you ever do find yourself with some free time, the feature to alert only if X spots are received within Y time would be most welcome. I leave everything running overnight with my antenna beamed towards Europe, so any early-morning trans-Atlantic activity to a new zone or entity will trip the alarm bells, but if only one spot, legit or bogus, arrives there's no need to crawl bleary-eyed into the shack on 3 hours' sleep. If I get 3 in 2 minutes, or even 2 in 30 seconds, then it's likely the start of a legit opening and it's time to caffeinate and get going. I'd say a similar condition for DXpeditions or needed entities would weed out fake spots. 


Dave AA6YQ
 

+ AA6YQ comments below

If you ever do find yourself with some free time, the feature to alert only if X spots are received within Y time would be most welcome. I leave everything running overnight with my antenna beamed towards Europe, so any early-morning trans-Atlantic activity to a new zone or entity will trip the alarm bells, but if only one spot, legit or bogus, arrives there's no need to crawl bleary-eyed into the shack on 3 hours' sleep. If I get 3 in 2 minutes, or even 2 in 30 seconds, then it's likely the start of a legit opening and it's time to caffeinate and get going. I'd say a similar condition for DXpeditions or needed entities would weed out fake spots.

+ Why not put a tablet next to your bed and use SpotCollector's web interface so you can directly determine whether it's worth getting up? See

<https://www.dxlabsuite.com/spotcollector/Help/WebBrowser.htm>

+ and

<http://www.dxlabsuite.com/spotcollector/WebAccess.jpg>

73,

Dave, AA6YQ


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.


Chad Kurszewski
 

That's correct.  AC0RA was in EM43 on Tuesday/Wesnesday this week.  I hope you didn't think it was false and got one of your two remaining EM grids.

Chad WE9V


Peter Dougherty
 
Edited

Well crap. I guess that did happen. I was getting hits on the call in Spot Collector, but JT Alert-X wasn't tweaking to whatever he was reporting. As I sit here and watch every other region getting these fantastic long-haul openings knowing NJ seems to get the dregs 99 times out of 100, then I see this. Shaping up to be One Of Those Mornings. If he was roving in EM43, though, I have to wonder why JTAlert-X didn't pick up on it, since it's usually VERY reliable in flagging new grids.

I guess I never really worried about domestic grids in the past, figuring they were a dime a dozen. But now that I'm over 500 (still wet behind the ears compared to many here, I'm sure) new grid flags are getting increasingly difficult, especially domestically. And it's funny how, when I look at my 6m grid worked/confirmed map in DX Atlas, everything falls off a cliff west of EM. I only have about 30% of grids worked in DM70-DM99, but about 95-98% of EM00-EM30. It's like the DM/EM divide is a DX wall. And the Canadian border is a much bigger DX wall. Looks like most Canadian hams don't pay much attention to 6m. My EN and FN grids all basically stop at the US-Canada border. Put down the maple syrup and the Timmies double-doubles and get up on six, eh? (I can say this...I'm also VE3THX; born and raised in the land of moose-and-elk).


iain macdonnell - N6ML
 

On Wed, Jun 17, 2020 at 7:13 PM Peter Dougherty <lists@w2irt.net> wrote:

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.
FWIW, there is an issue with the current version of SpotCollector when
the grid for a spot [database entry] is derived from the DXCC database
entry matching the station's callsign. In such cases, the spot
database entry is not supposed to be marked as needed, even if you do
need that grid, since the source of the grid data is not sufficiently
precise. There should be a fix in the next version of SpotCollector to
handle this properly. For me, this issue was most noticeable with VE
stations, where the grid would be one in the middle of the VE
province, most of which are in the middle of nowhere, hence needed.

Sorry that you missed out on EM43!

73,

~iain / N6ML


Dave AA6YQ
 

+ AA6YQ comments below

FWIW, there is an issue with the current version of SpotCollector when the grid for a spot [database entry] is derived from the DXCC database entry matching the station's callsign. In such cases, the spot database entry is not supposed to be marked as needed, even if you do need that grid, since the source of the grid data is not sufficiently precise. There should be a fix in the next version of SpotCollector to handle this properly. For me, this issue was most noticeable with VE stations, where the grid would be one in the middle of the VE province, most of which are in the middle of nowhere, hence needed.

+ The next version of SpotCollector, which includes the repair of this defect, is now being tested by two users.

73,

Dave, AA6YQ