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ADS-B changes (was: Re: [yaac-users] next YAAC build#198 created 2024-May-21)

 

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Greetings.

The ADS-B timeout parameter is in the port configuration panel for that port type. It's a control that allows you to set a time between 1 to 60 minutes. So go to File->Configure->Expert Mode, go to the Ports tab, select the row for the ADS-B port, and click Edit.

Alas, there is a bug in the rtl_adsb program where it may not die when the YAAC port is closed (either by editing the port or exiting YAAC), so you may have to hand-kill it and re-open the port.

As for the age times, those are the times since an ADS-B sentence was last successfully heard for a given aircraft. Note that keyword "successfully"; if there is a bit error in a received sentence causing a checksum failure, the sentence will be discarded and not counted as received. Distant aircraft will probably have higher error rates, causing slower updates.

Hope this helps.

Andrew, KA2DDO
author of YAAC

From: [email protected] <[email protected]> on behalf of Jon Adams
Sent: Wednesday, May 22, 2024 12:22:33 PM

Thanks for the update, Andrew, especially for the attention to ADS-B.

In searching through the new version, I haven't located the part about?

"11. in the ADS-B plugin, set the inactive station time interval separately
for aircraft, with a default inactive-before-purge time of 5 minutes
and a maximum of 60 minutes."

Where is that located? I went to View>Aircraft>Filter but it appears to be the standard filter settings for all stations, which I have set to 1 hour.?

This is in the truck, running a Win 11 box. The truck is parked. I have a/c that are now well over an hour old and (what i think is dead reckoning?) still showing as giant skidmarks %^)



Another thing I notice is that updating the screen seems to be at random times (the following is seconds after the top of the minute): 50 55 02 35 58 08 15 20 52 55 17 35 44 56 07 20 28 38 47?
Since there are sometimes as little as 3 seconds (52 to 55) and other times as much as 33 seconds (02 to 35) between screen updates, it doesn't seem to be a matter of processor overloading.?
--
Cheers and 73 - Jon N7UV
 

Hi Andrew -

Thanks for the info. I went to port setup and dialed it down to 1 min, and that seemed to help.



My mobile ADS-B setup is fairly sensitive. I don't worry about random a/c at extreme range, more that stuff in the area is reliably received.

The snail-trail/skidmark/dead reckoning is really messing things up. I live near many airports with significant traffic, and can hear hundreds of a/c within a 20 nm range. The problem seems to be that when a/c destinate at a particular airport, dead reckoning assumes they're still moving at some runway taxi speed (except for Sky Harbor KPHX, an ADSB-X field, where they are required to keep ADS-B on until they arrive at the stand). Though even that doesn't explain the long trails coming off the west end of the dual runways (they're landing/taking off to the west currently).?

I just changed the behavior to

and dialed down the maximum age to view to 30 min and time to keep to 1 hour.

Let's see what that does for me.

--
Cheers and 73 - Jon N7UV
 

Duh. The easiest thing was the most obvious. I went to View>Layers>Show Dead Reckoning and turned it off. My bad.
--
Cheers and 73 - Jon N7UV
 

As for the age times, those are the times since an ADS-B sentence was last successfully heard for a given aircraft. Note that keyword "successfully"; if there is a bit error in a received sentence causing a checksum failure, the sentence will be discarded and not counted as received. Distant aircraft will probably have higher error rates, causing slower updates.
The View>Aircraft list/table shows many dozens of a/c updating at intervals of 0-1 second. I'm fairly sure that it's not due to dropped or discarded packets. My point was about the somewhat random intervals between screen refreshes, sometimes a few seconds and other times over 30 seconds. I don't know what causes that randomization. As I said, it doesn't appear to be processor issues, as the list updates seemingly at 1 second intervals. Maybe it's the map refresh that gets bogged down? The refresh certainly takes a good fraction of a second, at least for this pc, so maybe there's just so many calls to rewrite the screen that something can't respond that quickly? The dashboard pseudo-LED for ADS-B RF is always green with short flashes of black. The ADS-B receiver is an RPi 4 so it can feed data pretty rapidly. Using a browser interface, I'm getting 400-600 decoded messages per second.

Anyway, I'll be out in the middle of nowhere over the weekend and will see how the refresh behaves in a less intense receiving environment.

Cheers and 73 - Jon N7UV

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