1 PLANE... BROADCASTING FOR 2? or Mini-Me?

spacellamaman

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Have seen this a couple of time over the past few months, a known A/C will be shown with a generic hex code sitting on top of it, within gps-margin-of-error distance. usually the unknown will pop in and out, and its hard getting a screen shot, though did just now, it's zoomed in quite severely (within wake turbulence range). most cases this has been with a 427th SOS plane, which brings up some interesting possibilities. just thought i'd mention it


AE272C 96-6042.png
 

freqhopping

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The planes with a ~before hex are TIS-B broadcasts. Sometimes they are duplicates of planes with a mode-S transponder, other times they are aircraft not equipped/not transmitting mode-S.
 

spacellamaman

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well i hate looking like a dummy twice on a topic, in such a short period of time....but here goes:

-2  278A51 AND CN235.jpg

96-6044 AND 278A51.jpg

96-6044.jpg

278A51 AND 96-6044.jpg



just to confirm, and i'll drop it after this, nothing seems odd about this to any of you tracking enthusiasts?

it just strikes me as interesting that the only time i see something like this, is when a CN-235 (one of the 96-60xx serials) is airborne around Ft Bragg.

also to clarify, the screen shots are grouped as two sets of two, one of each during an approximate 20 second timeblock, to highlight the info of each separate ID, with the mouse pointer sitting on the other ID so as to show info of both at the same time.

anyhoo, thanks again.
 

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spacellamaman

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Pretty sure every time I've seen this then looked to the sky it's always been just 1 aircraft...
yeah i am convinced of the same thing. i just don't understand what is going on exactly as there are no other aircraft in the same airspace that do this.

the CN235's are part of the "non-standard aircraft" inventory for the 427th SOS, and do a lot of low-level, lights-out training to the west of ft bragg, the general vicinity where i am located.

they appear to toggle their civilian-receivable data transmissions at will, as when they are training around KVUJ (which has good adsbx coverage, down to the tarmac) they are invisible on adsbx while other aircraft essentially beside them at the same altitude, show up just fine. I like to go out to watch/photograph them when they are in the area, but i get warning only via radio voice comms, and adsbx is frustratingly un-useful in most cases with them. sometimes they won't show up at all for an entire evening on adsbx, where other nights it will show them on the departing-plus-10-20 miles leg and then the final-10-20-miles-return leg back to Pope/Bragg and nothing in between.

i am just trying to broaden my understanding of their, shall we say, TTP's :)
 

freqhopping

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well i hate looking like a dummy twice on a topic, in such a short period of time....but here goes:

just to confirm, and i'll drop it after this, nothing seems odd about this to any of you tracking enthusiasts?

it just strikes me as interesting that the only time i see something like this, is when a CN-235 (one of the 96-60xx serials) is airborne around Ft Bragg.

also to clarify, the screen shots are grouped as two sets of two, one of each during an approximate 20 second timeblock, to highlight the info of each separate ID, with the mouse pointer sitting on the other ID so as to show info of both at the same time.

anyhoo, thanks again.

Did you even follow the link in my last post and read it?
 

spacellamaman

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Did you even follow the link in my last post and read it?
yes, that's why i said "dummy" again. i can't say i feel totally confident of my understanding. a single tis-b broadcast in an area that seems to only have them in relationship to a small group of airplanes is a bit confusing.

I see two separate tracks.
me too, like touching wingtips. or two separate devices separately collecting and transmitting data on board a single ship.
 

nycrich

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Okay it is the same aircraft. It is cause by errors in ADS-B feeds. Feeds come from a variety of sources including people like ourselves that have a 1090 Mhz antenna/software and contribute to these big sites like Flightaware, Radarbox24, etc. In exchange for providing a feed in our local area to these websites we get the premium packages that cost hundred of dollars for free, and helps these big websites with better tracking.
To make tracking accurate, these sites use a feature called MLAT for Mode S in ADS-B (where several monitors track the same aircraft and provide accurate/SYNC data information like a triangulation). If one site that is contributing has the wrong coordinates for their location the receiving servers from the big site is not in sync with all members contributing that aircraft location and will give duplicate position reports.
I know this problem because I was contributing to those 2 sites mentioned above and was causing a similar problem because my latitude and longitude coordinates was a bit off. The website identified my feeder finally and I fixed the issue with correct Lat/long for my location.
If you were to track the aircraft a couple hundred miles away the ghost image will disappear as the offending receiver (and yes here in Florida I could receive +250 miles out) will be out of receiving coverage to provide erroneous data . Also you will note that one aircraft will have full flight info and usually the ghost will default to generic info.
 
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consys

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Thank you nycrich for the explanation!!! I've been trying to understand the cause of the ghost images for a while. Much appreciated.
 
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