new record for me


#1

2233 aircraft seen, a record high for my sites, Thursday 11/17/2016, but the interesting thing is that it is the first time both site ID’s have matched up. 16907 is running through PlanePlotter, and 22047 is Piaware. Both are fed from the same remote Dump1090 instance on a RPi + 820T2 dongle. It’s always been interesting to see the discrepancies between the two processing systems, but today they came together on the final tally.


#2

Nicely done - I’ve only been running a receiver for a couple of weeks now but have already noticed that Thursdays and Sundays seem to be the busiest days here for me.

73 Keith.


#3

Yet another crazy track… And a new record distance…


#4

I suspect a badly set up transponder. We were multilaterating the same hexid in two completely different places at about the same time. You’re seeing the “other” position there.


#5

Yesterday was my best day by far overall.

i’ve had more ADS-B aircraft and reports on previous days but yesterday was very busy with MLAT and Other.


#6

First post, folks, take it easy on me :smiley:
I was out walking yesterday and using my cheapo windows tablet, dongle and an antenna picked up off eBay, noted down amongst others, a flight (Fin5) lat long coords(I’m a noob at this) and had found out this was just off the coast of Norway (I was roughly 20 miles west of Glasgow(Scotland) sitting at the top of the local golf course) and last logged the flight just off the Isle of Lewis. The Norweigan ref was approx 375 nm from me. I later checked if there was a 23cm amateur band (1296 Mhz) lift on and saw one contact made from the N of Scotland to the Netherlands around 16.00 UTC.


#7

I thought the same until I looked up the flight. It is where is was supposed to be according to its schedule, on its normal route, and shows up in FA history in that location in that window of time. Where were you seeing it at that time? (1204PM CST/1804UTC)


#8

FA’s mlat will pick one or the other, and it’s somewhat sticky, so it’s not that we’re producing two targets simultaneously. The “wrong” result, when we’re producing that at the mlat level, will get thrown away by the flight-tracking code as being implausibly far from the flightplan / existing positions.

Here’s one of the switchovers:



clock 1480121281 hexid A417A4 lat 26.09395 lon -100.07646 alt 6469
clock 1480123122 hexid A417A4 lat 33.08033 lon -115.42141 alt 30385


The N-number registration (and therefore hexcode) was cancelled (for export) in 2011 then reused in 2014; it is not unheard of that the transponder on the old aircraft never gets reprogrammed.

(I think there is a bug somewhere in the mlat results forwarding that ends up forwarding results to piawares for much longer than it should, which is why you sometimes see mlat results far from your receiver like this, but I can’t see where it is so far)


#9

Let me see if I understand what you are explaining… The actual hex I was seeing is from a misprogrammed transponder that was actually at lat 33.08033 lon -115.42141, well within my range, south of the border in Mexico, but the FA MLAT threw that one out and replaced it with the track from the transponder at lat 26.09395 lon -100.07646?


#10

Yes.

If you look at the FAA registry entry ( registry.faa.gov/aircraftinquiry … txt=N363CA ) the current registration is in California (so that one was probably the correct one), and the previous registration was deregistered for export to Mexico, so it seems likely that the new owners haven’t reprogrammed the transponder ID.